03339nas a2200253 4500008004100000022001400041245019100055210006900246260010600315300001400421490000700435520231200442653003202754653001002786653003002796653001702826653001002843100002402853700002502877700001902902700002202921700002402943856011802967 2010 eng d a0013-468600aPt-MoOx-carbon nanotube redox couple based electrocatalyst as a potential partner with polybenzimidazole membrane for high temperature polymer electrolyte membrane fuel cell applications0 aPtMoOxcarbon nanotube redox couple based electrocatalyst as a po aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR a2878-28870 v553 a

A redox couple based electrocatalyst comprising of Pt-Multi Wall Carbon NanoTube (Pt-MWCNT) promoted with molybdenum oxide (MoOx, 2 < x < 3) nanoparticles was prepared. The objective was to effectively organize the Pt-MoOx interface on the smooth MWCNT surface to overcome the practical difficulties associated with establishing such interface with Pt dispersed on carbon morphologies possessing surface irregularities. The present study revealed the importance of stringent controlling of the additive level for maintaining a balanced bifunctional behavior of the catalyst combination through the synergistic effects by the components and the need of a proton conducting membrane operable at high temperature to get better output from the Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems. An indigenously developed polybenzimidazole (PBI) membrane was used to fabricate a membrane electrode assembly (MEA) as it can be operated at higher temperatures compared to that of Nafion membranes. MoOx additive level was carefully controlled by monitoring the active Pt area by cyclic voltammetry. All prepared electrocatalysts were characterized by using HRTEM, XRD and XPS to get information on dispersion and morphology, crystalinity and oxidation state of different elements, respectively. The system prepared with 5% MoOx addition with respect to Pt (hereafter Pt-MoOx(5%)-MWCNT) displayed balanced active Pt area and excellent oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) activities. Rotating Disk Electrode (ROE) system was extensively utilized to understand the ORR kinetics and the favorable role of MoOx as the promoter in the reaction. The kinetic current (j(k)) measured at 0.02 V vs. Hg/Hg2SO4 electrode from the Koutecky-Levich plots was 9 times higher and the apparent activation energy during single cell evaluation was 27 kJ/mol lower for the MoOx promoted system, compared to the system without the additive. A higher operating temperature significantly favored the cell performance by a combined effect of enhancement in proton conductivity of the PBI membrane and possible kinetic benefit by the well postulated oxygen spill over effect by the MoOx type systems in some combinations involving such systems. (C) 2010 Elsevier Ltd. All rights reserved.

10aMethanol oxidation reaction10aMWCNT10aoxygen reduction reaction10aPBI membrane10aPEMFC1 aVellacheri, Ranjith1 aUnni, SreeKuttan, M.1 aNahire, Sandip1 aKharul, Ulhas, K.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/pt-moox-carbon-nanotube-redox-couple-based-electrocatalyst-potential-partner-001248nas a2200229 4500008004100000022001400041245008600055210006900141260007100210300001400281490000700295520042100302653001900723653001400742653003000756653002400786100002400810700002500834700002400859700001800883856011700901 2012 eng d a0897-475600aDisordered brownmillerite Ba2InCeO5+delta with enhanced oxygen reduction activity0 aDisordered brownmillerite Ba2InCeO5delta with enhanced oxygen re a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL a2823-28280 v243 a

A disordered brownmillerite, Ba2InCeO5+delta, with slight tetragonal distortion from ideal cubic perovskite is synthesized and its oxygen reduction reactivity tested. The material displayed oxygen reduction behavior in alkaline solution comparable to that of standard 40 wt % Pt/C catalyst and attractive activity characteristics which renders it a potential system for low temperature fuel cell applications.

10abrownmillerite10afuel cell10aoxygen reduction reaction10aRietveld refinement1 aJijil, Chamundi, P.1 aUnni, SreeKuttan, M.1 aSreekumar, Kurungot1 aDevi, Nandini uhttps://library.ncl.res.in/content/disordered-brownmillerite-ba2inceo5delta-enhanced-oxygen-reduction-activity-002386nas a2200253 4500008004100000022001400041245008400055210006900139260007100208300001600279490000600295520147900301653002101780653002001801653002001821653001401841653003001855100002501885700002701910700002801937700002701965700002401992856011602016 2015 eng d a1944-824400aCarbon nanohorn-derived graphene nanotubes as a platinum-free fuel cell cathode0 aCarbon nanohornderived graphene nanotubes as a platinumfree fuel a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV a24256-242640 v73 a

Current low-temperature fuel cell research mainly focuses on the development of efficient nonprecious electrocatalysts for the reduction of dioxygen molecule due to the reasons like exorbitant cost and scarcity of the current state-of-the-art Pt-based catalysts. As a potential alternative to such costly electrocatalysts, we report here the preparation of an efficient graphene nanotube based oxygen reduction electrocatalyst which has been derived from single walled nanohorns, comprising a thin layer of graphene nanotubes and encapsulated iron oxide nanopartides (FeGNT). FeGNT shows a surface area of 750 m(2)/g, which is the highest ever reported among the metal encapsulated nanotubes. Moreover, the graphene protected iron oxide nanoparticles assist the system to attain efficient distribution of Fe-N-x and quaternary nitrogen based active reaction centers, which provides better activity and stability toward the oxygen reduction reaction (ORR) in acidic as well as alkaline conditions. Single cell performance of a proton exchange membrane fuel cell by using FeGNT as the cathode catalyst delivered a maximum power density of 200 mW cm(-2) with Nafion as the proton exchange membrane at 60 degrees C. The facile synthesis strategy with iron oxide encapsulated graphitic carbon morphology opens up a new horizon of hope toward developing Pt-free fuel cells and metal-air batteries along with its applicability in other energy conversion and storage devices.

10acarbon nanohorns10acarbon nanotube10aelectrocatalyst10afuel cell10aoxygen reduction reaction1 aUnni, SreeKuttan, M.1 aIllathvalappil, Rajith1 aBhange, Siddheshwar, N.1 aPuthenpediakkal, Hasna1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/carbon-nanohorn-derived-graphene-nanotubes-platinum-free-fuel-cell-cathode-001962nas a2200241 4500008004100000022001400041245013300055210006900188260007500257300001400332490000600346520103800352653002101390653001801411653001501429653003001444653001301474100002501487700002901512700002401541700002601565856012901591 2015 eng d a2196-021600aCoSe2 supported on nitrogen-doped carbon nanohorns as a methanol-tolerant cathode for air-breathing microlaminar flow fuel cells0 aCoSe2 supported on nitrogendoped carbon nanohorns as a methanolt aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcSEP a1339-13450 v23 a

The synthesis of CoSe2 nanoparticles supported on nitrogendoped carbon nanohorns (CoSe2/NCNH) and the influence of the interaction of the metal centre with the NCNH on the oxygen reduction reaction (ORR) are reported. CoSe2/NCNH shows a 50 mV lower onset overpotential and a 150 mV positive shift in the half-wave potential compared to CoSe2 supported on carbon and carbon nanohorns. This suggests that the intrinsic activity and the density of active reaction centres of CoSe2 are modified by NCNHs. An air-breathing direct meth-anol microlaminar flow fuel cell (mLFFC) is constructed using CoSe2/NCNH as a methanol-tolerant cathode catalyst. A maximum power density of 10.05 mWcm(-2) and a maximum current density of 124.20 mAcm(-2) are achieved with CoSe2/NCNH compared to the non-doped catalyst, CoSe2/C and Pt/C with 5m methanol as the fuel. The improved activity of CoSe2/ NCNH is attributed to the peculiar morphology and the nitrogen doping of the carbon nanohorns. This catalyst could be a suitable alternative to Pt.

10acarbon nanohorns10achalcogenides10afuel cells10aoxygen reduction reaction10aplatinum1 aUnni, SreeKuttan, M.1 aMora-Hernandez, Juan, M.1 aKurungot, Sreekumar1 aAlonso-Vante, Nicolas uhttps://library.ncl.res.in/content/cose2-supported-nitrogen-doped-carbon-nanohorns-methanol-tolerant-cathode-air-breathing-002350nas a2200241 4500008004100000022001400041245013100055210006900186260007100255300001400326490000600340520141500346653003301761653001901794653002001813653002601833653003001859653002401889653001901913100002401932700002401956856012801980 2015 eng d a2155-543500aCu-Pt nanocage with 3-D electrocatalytic surface as an efficient oxygen reduction electrocatalyst for a primary Zn-air battery0 aCuPt nanocage with 3D electrocatalytic surface as an efficient o a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a1445-14520 v53 a

Cu-Pt nanocage (CuPt-NC) intermetallic structures have been prepared by an in situ galvanic displacement reaction. The structures are found to be well organized within the framework demarcated with distinguishing arms, having clear edges and corners with a size of similar to 20 nm. The unique nanocage structure possessing large specific surface area and better structural integrity helps to achieve improved electrochemical oxygen reduction reaction activity and stability in alkaline solution in comparison to the commercially available 20 wt % Pt/C. CuPt-NC shows 50 mV positive onset potential shift with significantly higher limiting current in comparison to Pt/C. Interestingly, CuPt-NC has shown 2.9- and 2.5-fold improved mass activity and specific activity, respectively, for ORR at 0.9 V vs RHE in comparison to Pt/C. Moreover, the stability of CuPt-NC has been tested by an accelerated durability test under alkaline conditions. CuPt-NC has been subsequently utilized as the air electrode in a primary Zn-air battery and is found to possess 1.30- and 1.34-fold improved power density and current density at 1 V, respectively, in comparison to the state-of-the-art Pt/C catalyst. In addition, CuPt-NC has shown several hours of constant discharge stability at 20 mA cm(-2) with a specific capacity of 560 mAh gZn(-1) and energy density of 728 Wh kgZn(-1) in the primary Zn-air battery system.

10a3-D electrocatalytic surface10aCu-Pt nanocage10aelectrocatalyst10agalvanic displacement10aoxygen reduction reaction10asolvothermal method10aZn-air battery1 aDhavale, Vishal, M.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/cu-pt-nanocage-3-d-electrocatalytic-surface-efficient-oxygen-reduction-electrocatalyst-001867nas a2200241 4500008004100000022001400041245011600055210006900171260007100240300001400311490000600325520096600331653001901297653001401316653002001330653003001350653002401380100002401404700002801428700002401456700001801480856012701498 2015 eng d a1944-824400aEffect of b site coordination environment in the ORR activity in disordered brownmillerites Ba2In2-xCexO5+delta0 aEffect of b site coordination environment in the ORR activity in a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB a3041-30490 v73 a

Ba2In2O5 brownmillerites in which the In site is progressively doped with Ce exhibit excellent oxygen reduction activity under alkaline conditions. Ce doping leads to structural changes advantageous for the reaction. Twenty-five percent doping retains the ordered structure of brownmillerite with alternate layers of tetrahedra and octahedra, whereas further increase in Ce concentration creates disorder. Structures with disordered oxygen atoms/vacancies are found to be better oxygen reduction reaction catalysts probably aided by isotropic ionic conduction, and Ba2In0.5Ce1.5O5+delta is the most active. This enhanced activity is correlated to the more symmetric Ce site coordination environment in this compound. Stoichiometric perovskite BaCeO3 with the highest concentration of Ce shows very poor activity emphasizing the importance of oxygen vacancies, which facilitate O-2 adsorption, in tandem with catalytic sites in oxygen reduction reactions.

10abrownmillerite10afuel cell10aoxygen disorder10aoxygen reduction reaction10aRietveld refinement1 aJijil, Chamundi, P.1 aBhange, Siddheshwar, N.1 aKurungot, Sreekumar1 aDevi, Nandini uhttps://library.ncl.res.in/content/effect-b-site-coordination-environment-orr-activity-disordered-brownmillerites-ba2in2-002323nas a2200241 4500008004100000022001400041245014400055210006900199260010200268300001200370490000700382520137800389653001501767653001101782653001101793653003001804653001401834100002401848700002401872700002401896700003001920856013101950 2015 eng d a0250-470700aElectrochemical preparation of nitrogen-doped graphene quantum dots and their size-dependent electrocatalytic activity for oxygen reduction0 aElectrochemical preparation of nitrogendoped graphene quantum do aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScAPR a435-4420 v383 a

Here we report a remarkable transformation of nitrogen-doped multiwalled carbon nanotubes (MWCNTs) to size selective nitrogen-doped graphene quantum dots (N-GQDs) by a two-step electrochemical method. The sizes of the N-GQDs strongly depend on the applied anodic potential, moreover increasing potential resulted in a smaller size of N-GQDs. These N-GQDs display many unusual size-dependant optoelectronic (blue emission) and electrocatalytic (oxygen reduction) properties. The presence of N dopants in the carbon framework not only causes faster unzipping of MWCNTs but also provides more low activation energy site for enhancing the electrocatalytic activity for technologically daunting reactions like oxygen reduction. The smaller size of N-GQDs has shown better performance as compared to the large N-GQDs. Interestingly, N-GQDs-3 (size = 2.5 +/- 0.3 nm, onset potential = 0.75 V) show a 30-mV higher positive onset potential shift compared to that of N-GQDs-2 (size = 4.7 +/- 0.3 nm, onset potential = 0.72 V) and 70 mV than that of N-GQDs-1 (size = 7.2 +/- 0.3, onset potential = 0.68 V) for oxygen reduction reaction (ORR) in a liquid phase. These result in the size-dependent electrocatalytic activity of N-GQDs for ORR as illustrated by the smaller sized N-GQDs (2.5 +/- 0.3 nm) undoubtedly promising metal-free electrocatalysts for fuel cell applications.

10afuel cells10aMWCNTs10aN-GQDs10aoxygen reduction reaction10aunzipping1 aShinde, Dhanraj, B.1 aDhavale, Vishal, M.1 aKurungot, Sreekumar1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-preparation-nitrogen-doped-graphene-quantum-dots-and-their-size-dependent-002716nas a2200229 4500008004100000022001400041245017200055210006900227260007100296300001600367490000600383520177500389653002002164653001702184653003002201653003402231653002302265100002302288700002402311700002402335856012702359 2015 eng d a1944-824400aSurface-tuned Co3O4 nanoparticles dispersed on nitrogen-doped graphene as an efficient cathode electrocatalyst for mechanical rechargeable zinc-air battery application0 aSurfacetuned Co3O4 nanoparticles dispersed on nitrogendoped grap a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a21138-211490 v73 a

The most vital component of the fuel cells and metal air batteries is the electrocatalyst, which can facilitate the oxygen reduction reaction (ORR) at a significantly reduced overpotential. The present work deals with the development of surface-tuned cobalt oxide (Co3O4) nanoparticles dispersed on nitrogen-doped graphene as a potential ORR electrocatalyst possessing some unique advantages. The thermally reduced nitrogen-doped graphene (NGr) was decorated with three different morphologies of Co3O4 nanoparticles, viz., cubic, blunt edged cubic, and spherical, by using a simple hydrothermal method. We found that the spherical Co3O4 nanoparticle supported NGr catalyst (Co3O4-SP/NGr-24h) has acquired a significant activity makeover to display the ORR activity closely matching with the state-of-the-art Pt supported carbon (PtC) catalyst in alkaline medium. Subsequently, the Co3O4-SP/NGr-24h catalyst has been utilized as the air electrode in a Zn-air battery, which was found to show comparable performance to the system derived from PtC. Co3O4-SP/NGr-24h catalyst has shown several hours of flat discharge profile at the discharge rates of 10, 20, and 50 mA/cm(2) with a specific capacity and energy density of similar to 590 mAh/g(-zn) and,840 Wh/kg(-zn), respectively, in the primary Zn-air battery system. In conjunction, Co3O4-SP/NGr-24h has outperformed as an air electrode in mechanical rechargeable Zn-air battery as well, which has shown consistent flat discharge profile with minimal voltage loss at a discharge rate of 50 mA/cm(2). The present results, thus demonstrate that the proper combination of the tuned morphology of Co3O4 with NGr will be a promising and inexpensive material for efficient and ecofriendly cathodes for Zn-air batteries.

10aelectrocatalyst10amixed facets10aoxygen reduction reaction10arechargeable zinc-air battery10asurface morphology1 aSingh, Santosh, K.1 aDhavale, Vishal, M.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/surface-tuned-co3o4-nanoparticles-dispersed-nitrogen-doped-graphene-efficient-cathode-002005nas a2200301 4500008004100000022001400041245016600055210006900221260000800290300001600298490000600314520094300320653002301263653001901286653001901305653003001324653001801354653001001372100001801382700002601400700002401426700002401450700003101474700003001505700002101535700002001556856012701576 2016 eng d a1944-824400aGraphene oxide sheathed ZIF-8 microcrystals: engineered precursors of nitrogen-doped porous carbon for efficient oxygen reduction reaction (ORR) electrocatalysis0 aGraphene oxide sheathed ZIF8 microcrystals engineered precursors cNOV a29373-293820 v83 a

Nitrogen containing mesoporous carbon obtained by the pyrolysis of graphene oxide (GO) wrapped ZIF-8 (Zeolitic Imidazolate Frameworks-8) micro crystals is demonstrated to be an efficient catalyst for the oxygen reduction reaction (ORR). ZIF-8 synthesis in the presence of GO sheets helped to realize layers of graphene oxide over ZIF-8 microcrystals and the sphere-like structures thus obtained, on heat treatment, transformed to highly porous carbon with a nitrogen content of about 6.12% and surface area of 502 m(2)/g. These catalysts with a typical micromeso porous architecture exhibited an onset potential of 0.88Vvs RHE in a four electron pathway and also demonstrated superior durability in alkaline medium compared to that of the commercial Pt/C catalyst. The N-doped porous carbon derived from GO sheathed ZIF-8 core shell structures could therefore be employed as an efficient electrocatalyst for fuel cell applications.

10aalkaline fuel cell10agraphene oxide10aN-doped carbon10aoxygen reduction reaction10aporous carbon10aZIF-81 aThomas, Minju1 aIllathvalappi, Rajith1 aKurungot, Sreekumar1 aNair, Balagopal, N.1 aMohamed, Abdul, Azeez Peer1 aAnilkumar, Gopinathan, M.1 aYamaguchi, Takeo1 aHareesh, U., S. uhttps://library.ncl.res.in/content/graphene-oxide-sheathed-zif-8-microcrystals-engineered-precursors-nitrogen-doped-porous02299nas a2200253 4500008004100000022001400041245014600055210006900201260007500270300001400345490000700359520131800366653002001684653002001704653003001724653002001754653001701774100002901791700002401820700002601844700002001870700002401890856013101914 2016 eng d a1616-301X00aNanoporous graphene enriched with Fe/Co-N active sites as a promising oxygen reduction electrocatalyst for anion exchange membrane fuel cells0 aNanoporous graphene enriched with FeCoN active sites as a promis aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAPR a2150-21620 v263 a

Here, a simple but efficient way is demonstrated for the preparation of nanoporous graphene enriched with Fe/Co-nitrogen-doped active sites (Fe/Co-NpGr) as a potential electrocatalyst for the electrochemical oxygen reduction reaction (ORR) applications. Once graphene is converted into porous graphene (pGr) by a controlled oxidative etching process, pGr can be converted into a potential electrocatalyst for ORR by utilizing the created edge sites of pGr for doping nitrogen and subsequently to utilize the doped nitrogens to build Fe/Co coordinated centers (Fe/Co-NpGr). The structural information elucidated using both XPS and TOF-SIMS study indicates the presence of coordination of the M-N (M = Fe and Co)-doped carbon active sites. Creation of this bimetallic coordination assisted by the nitrogen locked at the pore openings is found to be helping the system to substantially reduce the overpotential for ORR. A 30 mV difference in the overpotential () with respect to the standard Pt/C catalyst and high retention in half wave potential after 10 000 cycles in ORR can be attained. A single cell of an anion exchange membrane fuel cell (AEMFC) by using Fe/Co-NpGr as the cathode delivers a maximum power density of approximate to 35 mWcm(-2) compared to 60 mWcm(-2) displayed by the Pt-based system.

10aelectrocatalyst10anitrogen doping10aoxygen reduction reaction10aporous grapheme10aquantum dots1 aPalaniselvam, Thangavelu1 aKashyap, Varchaswal1 aBhange, Siddeswar, N.1 aBaek, Jong-Beom1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/nanoporous-graphene-enriched-feco-n-active-sites-promising-oxygen-reduction-electrocatalyst02821nas a2200349 4500008004100000022001400041245018300055210006900238260000800307300001400315490000600329520162200335653002201957653002001979653001201999653001402011653002402025653002402049653002402073653002102097653002002118653001702138653003002155653001602185653001402201653002702215653003402242100002402276700002302300700002402323856012402347 2017 eng d a2365-654900aActivity tuning of cobalt ferrite nanoparticles anchored on N-doped reduced graphene oxide as a potential oxygen reduction electrocatalyst by Zn substitution in the spinel matrix0 aActivity tuning of cobalt ferrite nanoparticles anchored on Ndop cSEP a7845-78530 v23 a

Development of highly efficient and durable ORR catalysts by using non-platinum group metals (such as Co, Fe, Mn, and Zn) is a challenging task in the forward path towards the realization of low-cost energy devices in the commercial stream. The present work deals with an effective strategy wherein an efficient Pt-free electrocatalyst for oxygen reduction reaction (ORR) is prepared by stoichiometrically substituting some fraction of Fe with Zn in cobalt ferrite and anchoring these spinel nanoparticles on nitrogen doped reduced graphene oxide (N-rGO). Zn substitution is found to be significantly altering the ratio of Fe2+/Fe3+ in the cobalt ferrite nanocrystal system with a concomitant promotional influence on its electrocatalytic activity towards ORR. The nanoparticle composition with a Co, Fe and Zn molar ratio of 1.0:1.7:0.3, represented by the formula CoFe1.7Zn0.3O4(CFZn(0.3)), supported over N-rGO has shown 10 mV and 20 mV positive shift in the onset and half-wave potentials, respectively, for ORR in 0.1 M KOH in comparison to the nanoparticles of CoFe2O4 supported over N-rGO (CF/N-rGO). The optimum Zn substitution is found to be narrowing down the difference with the state-of-the-art Pt/C for ORR by 100 and 110 mV in terms of the onset and half-wave potentials, respectively. Most significantly, the homemade catalyst is found to be clearly outperforming the Pt catalyst in terms of the limiting current density and electrochemical durability.

10aCarbon Nano-fiber10aCathod Catalyst10aCoFe2O410aEvolution10aMagnetic-properties10aMembrane fuel- Cell10aMetal-Air Batteries10aN-doped graphene10aNanocrystalline10ananocrystals10aoxygen reduction reaction10aperformance10aPlatinium10asolvothermal synthesis10aZn substituted cobalt ferrite1 aKashyap, Varchaswal1 aSingh, Santosh, K.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/activity-tuning-cobalt-ferrite-nanoparticles-anchored-n-doped-reduced-graphene-oxide02503nas a2200289 4500008004100000022001400041245016700055210006900222260000800291300001400299490000600313520146900319653002001788653001401808653002201822653003001844100002501874700002701899700002401926700002401950700001801974700002101992700003002013700002002043700002002063856013002083 2017 eng d a2365-654900aChitosan intercalated metal organic gel as a green precursor of fe entrenched and fe distributed N-doped mesoporous graphitic carbon for oxygen reduction reaction0 aChitosan intercalated metal organic gel as a green precursor of  cSEP a8762-87700 v23 a

Herein, we present Metal-Organic Gel intercalated with chitosan, a `green'' precursor for the synthesis of intrinsic N-doped Fe entrenched (CHI-TMA-Fe-CW) and Fe distributed mesoporous graphitic carbon structures (CHI-TMA-Fe-CW-M1) with appreciable Oxygen Reduction Reaction (ORR) activity in alkaline medium. Modulation of the synthetic protocol as a function of reaction kinetics and gelation time while maintaining identical pyrolysis conditions (900 degrees C, flowing N-2 atmosphere) improves the microstructure, surface area and Fe distribution of the graphitic structures (CHI-TMA-Fe-CW-M1). CHI-TMA-Fe-CW has a Fe entrenched graphitic nanocapsule like morphology while Fe distributed mesoporous graphitic carbon sheets, with a specific surface area value of 565 m(2) g(-1) obtained by modulating the synthesis chemistry in CHI-TMA-Fe-CW-M1. The higher percentage of graphitic N in CHI-TMA-Fe-CW-M1 apparent from the XPS data validate that the modified synthetic method favours creation of more graphitic N sites contributing for better catalytic performance. CHI-TMA-Fe-CW-M1 catalyst exhibited comparable electrocatalytic activity with that of the commercially available Pt/C via an efficient four-electron-dominant ORR pathway with a positive onset potential value of 0.925 V vs RHE. Good durability of CHI-TMA-Fe-CW-M1 after 5000 cycles further confirm the prospects of MOG-chitosan and the feasibility to be used as a potential catalyst for ORR.

10aelectrocatalyst10afuel cell10aMetal-Organic-Gel10aoxygen reduction reaction1 aShijina, Kottarathil1 aIllathvalappil, Rajith1 aKurungot, Sreekumar1 aNair, Balagopal, N.1 aMohamed, Peer1 aYamaguchi, Takeo1 aAnilkumar, Gopinathan, M.1 aHareesh, U., S.1 aSailaja, G., S. uhttps://library.ncl.res.in/content/chitosan-intercalated-metal-organic-gel-green-precursor-fe-entrenched-and-fe-distributed-n02901nas a2200301 4500008004100000022001400041245013800055210006900193260000800262300001400270490000600284520183300290653003802123653002502161653002402186653003002210653002802240653001902268100002302287700002402310700002102334700002802355700001502383700002302398700002202421700002502443856013102468 2017 eng d a2155-543500aEfficient and durable oxygen reduction electrocatalyst based on CoMn alloy oxide nanoparticles supported over N-doped porous graphene0 aEfficient and durable oxygen reduction electrocatalyst based on  cOCT a6700-67100 v73 aTransition metal oxide derived materials are very important for various applications, such as electronics, magnetism, catalysis, electrochemical energy conversion, and storage. Development of efficient and durable catalysts for the oxygen reduction reaction (ORR), an important reaction in fuel cells and metal air batteries, is highly desirable. Moreover, the futuristic catalysts for these applications need to be costeffective in order to ensure a competitive edge for these devices in the energy market. This article describes the synthesis of a cost-effective and efficient electrocatalyst for ORR It is based on supporting CoMn alloy oxide nano particles on N-doped porous graphene through a simple and scalable microwave irradiation method. Microwave irradiation was found to be very crucial for the fast creation of pores in the graphene framework with a concomitant formation of the CoMn alloy oxide nanoparticles. A series of catalysts have been synthesized by varying the Co:Mn ratio, among which, the one with the Co:Mn ratio of 2:1 [designated as CoMn/pNGr(2:1)] displayed remarkably higher ORR activity in 0.1 M KOH solution. It showed a similar to 60 mV potential shift with a low Tafel slope of 74 mV/decade, which is comparable to that derived from the commercial Pt/C catalyst. This high activity of CoMn/pNGr(2:1) has been credited to the cooperative effect arising from the metal entities and the defects present in the N-doped porous graphene. Finally, real system-level validations of the use of CoMn/pNGr(2:1) as cathode catalyst could be performed by fabricating and testing single-cells of an anion-exchange membrane fuel cell (AEMFC) and a primary Zn-air battery, which successfully demonstrated the efficiency of the catalyst to facilitate ORR in real integrated systems of the single-cell assemblies.10aanion-exchange membrane fuel cell10acooperativity effect10amicrowave synthesis10aoxygen reduction reaction10aporous N-doped graphene10aZn-air battery1 aSingh, Santosh, K.1 aKashyap, Varchaswal1 aManna, Narugopal1 aBhange, Siddheshwar, N.1 aSoni, Roby1 aBoukherroub, Rabah1 aSzunerits, Sabine1 aKurungot, Sreekurnar uhttps://library.ncl.res.in/content/efficient-and-durable-oxygen-reduction-electrocatalyst-based-comn-alloy-oxide-nanoparticles02277nas a2200289 4500008004100000022001400041245014000055210006900195260000800264300001400272490000600286520128800292653002001580653001401600653002601614653003001640653001001670100001801680700002701698700002401725700002401749700001801773700003001791700002101821700002001842856012501862 2018 eng d a2365-654900aMorphological ensembles of N-doped porous carbon derived from ZIF-8/Fe-graphene nanocomposites: processing and electrocatalytic studies0 aMorphological ensembles of Ndoped porous carbon derived from ZIF cAUG a8688-86970 v33 a

Engineering the active site density of porous carbon catalysts for enhanced electrocatalytic activity is the current focus in the quest for economically viable fuel cells. Herein, we synthesise ZIF-8/Fe-graphene composites for the formation of N and Fe co-doped carbon with diverse morphologies ranging from tubes and sheets to frameworks of carbon. A synthetic strategy involving the one pot synthesis of ZIF-8 based composites is accomplished by the reaction of 2-methylimidazole with mixed Zn/Fe salt solution containing graphene dispersions. The high temperature heat treatment of this precursor mix yielded micro-meso porous architectures of N, Fe co-doped carbon with dispersions of Fe/Fe3C. An onset potential value of 0.95 V and a half-wave potential of 0.82 V coupled with excellent durability and stability in alkaline medium indicated improved electrocatalytic performances over its commercial Pt/C counterpart. The appreciable electrocatalytic properties of the synthesized carbon are attributed to its morphological diversity, hybrid structure, high N doping and its heteroporous characteristics. The dispersed Fe/Fe3C and FeNx sites facilitated enhanced oxygen adsorption and the graphene inclusions in the composite provided retention of high nitrogen contents.

10aelectrocatalyst10afuel cell10aN- Fe co-doped carbon10aoxygen reduction reaction10aZIF-81 aThomas, Minju1 aIllathvalappil, Rajith1 aKurungot, Sreekumar1 aNair, Balagopal, N.1 aMohamed, Peer1 aAnilkumar, Gopinathan, M.1 aYamaguchi, Takeo1 aHareesh, U., S. uhttps://library.ncl.res.in/content/morphological-ensembles-n-doped-porous-carbon-derived-zif-8fe-graphene-nanocomposites03126nas a2200205 4500008004100000022001400041245017200055210006900227260000800296300001400304490000600318520228000324653003502604653003002639653003002669653004102699100002402740700002402764856013202788 2018 eng d a2155-543500aZirconium-substituted cobalt ferrite nanoparticle supported n-doped reduced graphene oxide as an efficient bifunctional electrocatalyst for rechargeable Zn-air battery0 aZirconiumsubstituted cobalt ferrite nanoparticle supported ndope cAPR a3715-37260 v83 a

Solvothermal synthesis of zirconium-substituted cobalt ferrite nanoparticles was accomplished by the introduction of zirconium (Zr) in the spinel matrix to obtain a cost-effective and robust electrocatalyst that does not use noble metals. A variation in the cobalt ferrite structure CoFe2−xZrxO4 with Zr (0.1−0.4) substitution has significantly altered the overpotential for the electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), leading to an optimum composition of CFZr(0.3). The incorporation of the foreign Zr4+ ion in the cobalt ferrite spinel lattices has effectively enhanced the oxygen evolution reaction (OER) activity in comparison to the parent cobalt ferrite (CF) nanocrystals. However, a nominal change in the ORR current density has been observed due to Zr incorporation. For the OER, the Zr-substituted catalyst has shown a 40 mV negative shift in the overpotential in comparison with the CF nanoparticles at 10 mA/cm2 current density. Interestingly, the in situ grafting of Zr-substituted cobalt ferrite nanoparticles over N-doped reduced graphene oxide (CFZr(0.3)/N-rGO) results in remarkably enhanced performance during the ORR and moderately favored the OER with an overall potential difference (ΔE) of 0.840 V. The enhanced bifunctional electrocatalytic activity of the material is crucial for the fabrication of high-performance rechargeable Zn−air batteries (ZABs). The prepared catalyst exhibited an overpotential of 80 mV for the ORR in comparison with the state-of-the-art (Pt/C) catalyst and an overpotential of 340 mV at 10 mA/cm2 current density for the OER from the standard value (1.23 V vs RHE). This potential bifunctional electrocatalyst has been employed as an electrode material for the fabrication of a primary ZAB, where it exhibited discharge capacities of 727 and 730 mAh/g at current densities of 20 and 30 mA/cm2 , respectively, under ambient conditions. The notable performance of the catalyst as a bifunctional material is observed during the cycling of the rechargeable ZAB. The prepared catalyst showed an increase of 200 mV in the overall operating overpotential after cycling for 10 cycles at 15 mA/cm2 in comparison to the 350 mV increase shown by the Pt/C catalyst.

10aN-doped reduced graphene oxide10aOxygen Evolution Reaction10aoxygen reduction reaction10azirconium-substituted cobalt ferrite1 aKashyap, Varchaswal1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/zirconium-substituted-cobalt-ferrite-nanoparticle-supported-n-doped-reduced-graphene-oxide-002359nas a2200277 4500008004100000022001400041245014700055210006900202260000800271300000800279490000600287520143600293653001501729653001601744653003001760653001401790653001301804653001901817653001801836653002101854100002801875700002101903700001501924700001901939856012301958 2019 eng d a2296-264600aElectrocatalysis of oxygen reduction reaction on shape-controlled pt and pd nanoparticles-importance of surface cleanliness and reconstruction0 aElectrocatalysis of oxygen reduction reaction on shapecontrolled cOCT a6480 v73 a

Shape-controlled precious metal nanoparticles have attracted significant research interest in the recent past due to their fundamental and scientific importance. Because of their crystallographic-orientation-dependent properties, these metal nanoparticles have tremendous implications in electrocatalysis. This review aims to discuss the strategies for synthesis of shape-controlled platinum (Pt) and palladium (Pd) nanoparticles and procedures for the surfactant removal, without compromising their surface structural integrity. In particular, the electrocatalysis of oxygen reduction reaction (ORR) on shape-controlled nanoparticles (Pt and Pd) is discussed and the results are analyzed in the context of that reported with single crystal electrodes. Accepted theories on the stability of precious metal nanoparticle surfaces under electrochemical conditions are revisited. Dissolution, reconstruction, and comprehensive views on the factors that contribute to the loss of electrochemically active surface area (ESA) of nanoparticles leading to an inevitable decrease in ORR activity are presented. The contribution of adsorbed electrolyte anions, in-situ generated adsorbates and contaminants toward the ESA reduction are also discussed. Methods for the revival of activity of surfaces contaminated with adsorbed impurities without perturbing the surface structure and its implications to electrocatalysis are reviewed.

10aAdsorption10aDissolution10aoxygen reduction reaction10aPalladium10aplatinum10areconstruction10ashape-control10asurface cleaning1 aDevivaraprasad, Ruttala1 aNalajala, Naresh1 aBera, Bapi1 aNeergat, Manoj uhttps://library.ncl.res.in/content/electrocatalysis-oxygen-reduction-reaction-shape-controlled-pt-and-pd-nanoparticles02395nas a2200241 4500008004100000022001400041245009700055210006900152260000900221300001400230490000600244520158800250653001901838653002401857653001401881653003001895653002101925100002401946700001601970700001501986700002402001856012802025 2019 eng d a2196-021600aMedium modulated oxygen reduction activity of Fe/Co active centre-engrafted electrocatalysts0 aMedium modulated oxygen reduction activity of FeCo active centre cJUN  a2956-29640 v63 a

Iron and cobalt metal atoms are effective active centers for the synthesis of carbon-based noble-metal-free catalysts for the oxygen reduction reaction (ORR) owing to their cost-effective intrinsic activity and tunable properties. Annealing of the active center with the conducting carbon enhances the ORR activity significantly. Herein, we have engrafted Fe and Co active centers in the homemade conducting carbon and the ORR performance has been closely observed under acidic and basic pH conditions to understand the influence of the medium and participating moieties towards the performance. In the half-cell reaction, the onset potential and half-wave potential for ORR are governed by the surface intermediates and concomitantly driven by the adsorption energies of the intermediates over the active centers. The iron and cobalt active center-engrafted carbon catalyst behaves differently in acidic and basic electrolytes owing to the dissociation of the surface intermediates. The iron-based catalyst shows improved onset potential against the cobalt-based one. Similarly, the cobalt-based catalyst shows improved half-wave potential against the iron active-center-grafted catalyst. The combined synergistic effect of the two catalysts is realized in the composition represented as Fe/2Co-N-GVC, where improved onset and half-wave potentials are noted in basic medium. A significant variation in the activity of the catalyst is observed as the medium changes from acidic to basic and the effect is directly associated with the surface adsorption of the intermediates.

10aactive centers10ahalf-wave potential10aMechanism10aoxygen reduction reaction10atransition state1 aKashyap, Varchaswal1 aAnand, Aljo1 aSoni, Roby1 aSreekumar, Kurungot uhttps://library.ncl.res.in/content/medium-modulated-oxygen-reduction-activity-feco-active-centre-engrafted-electrocatalysts01108nas a2200277 4500008004100000022001400041245015900055210006900214260000900283300001400292490000600306520012200312653002100434653002600455653001500481653003000496653002700526100002400553700002000577700001600597700001900613700002200632700002500654700002000679856013100699 2020 eng d a2574-096200aBimetallic palladium nickel nanoparticles anchored on carbon as high-performance electrocatalysts for oxygen reduction and formic acid oxidation reactions0 aBimetallic palladium nickel nanoparticles anchored on carbon as  cSEP  a9285-92950 v33 a

{Herein, we report the synthesis of carbon-supported palladium-nickel electrocatalysts (ECs) (Pd4-xNix/C ECs

10aelectrocatalysts10aFormic Acid Oxidation10afuel cells10aoxygen reduction reaction10apalladium-nickel alloy1 aGoswami, Chiranjita1 aSaikia, Himadri1 aTada, Kohei1 aTanaka, Shingo1 aSudarsanam, Putla1 aBhargava, Suresh, K.1 aBharali, Pankaj uhttps://library.ncl.res.in/content/bimetallic-palladium-nickel-nanoparticles-anchored-carbon-high-performance-electrocatalysts02390nas a2200217 4500008004100000022001400041245015200055210006900207260000800276300001400284490000600298520158300304653001901887653001501906653001801921653002601939653003001965100002701995700002402022856012602046 2020 eng d a2196-021600aCo (9) S (8) nanoparticle-supported nitrogen-doped carbon as a robust catalyst for oxygen reduction reaction in both acidic and alkaline conditions0 aCo 9 S 8 nanoparticlesupported nitrogendoped carbon as a robust  cJUL a3123-31340 v73 a

The present work illustrates the synthesis of an efficient and durable catalyst for electrochemical oxygen reduction reaction (ORR) which is active both in the alkaline and acidic conditions by dispersing few-layer graphitic carbon coated Co(9)S(8)nanoparticles on the nitrogen-doped carbon (NVC-G) support (Co9S8/NVC-G). The size of the Co(9)S(8)nanoparticles is nearly 7-8 nm and the particles are found to be dispersed homogeneously on the NVC-G support. The few-layer graphitic carbon formed on the surface of Co(9)S(8)nanoparticles is assisting to accomplish their small size and it also prevents agglomeration of the nanoparticles. The ORR activity of the obtained material was analyzed in both 0.1 M KOH and 0.5 M H(2)SO(4)solutions. Co9S8/NVC-G displays nearly 70 mV overpotential compared to thestate-of-the-artPt/C in 0.1 M KOH solution. The half-wave potential (E-1/2) difference of the present system is nearly 75 mV with the commercial Pt/C. Co9S8/NVC-G displays promising ORR activity in the acidic conditions as well with nearly 140 mV overpotential compared to its Pt/C counterpart. The system shows about 170 mV lowerE(1/2)value with Pt/C. The system shows good stability both in acidic and basic conditions compared to the Pt/C system. Finally, testing of a single cell of a polymer electrolyte membrane fuel cell (PEMFC) was performed by employing Co9S8/NVC-G as the cathode catalyst and Nafion-212 as the proton exchange membrane. The system displays a maximum power density of 245 mW cm(-2)in H-2-O(2)and 115 mW cm(-2)in H-2-air feeding conditions.

10acobalt sulfide10afuel cells10aNanoparticles10anitrogen-doped carbon10aoxygen reduction reaction1 aIllathvalappil, Rajith1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/co-9-s-8-nanoparticle-supported-nitrogen-doped-carbon-robust-catalyst-oxygen-reduction02872nas a2200253 4500008004100000022001400041245010000055210006900155260000800224300001400232490000600246520202700252653002002279653002002299653001402319653003002333653001602363100002802379700001502407700001902422700002302441700002402464856013002488 2020 eng d a2574-097000aFeNx/FeSx-anchored carbon sheet-carbon nanotube composite electrocatalysts for oxygen reduction0 aFeNxFeSxanchored carbon sheetcarbon nanotube composite electroca cMAR a2234-22450 v33 a

Even though various Pt-free electrocatalysts for oxygen reduction reaction (ORR) have been introduced, many of them are found to be active only in alkaline conditions. Considering Nafion, phosphoric acid-doped polybenzimidazole (PBI), and so on as the prominent ionomer membranes, used in the commercially available polymer electrolyte membrane fuel cells (PEMFCs), it becomes important that any development on the Pt-free catalysts should ensure the better ORR performance under acidic conditions. The present work effectively tackles this issue, where an ORR-based catalyst could be prepared with simultaneous incorporation of both Fe-N and Fe-S active sites on in situ generated carbon sheets which are spatially separated by the carbon nanotube (CNT) network. This catalyst shows ability to perform under both acidic and basic conditions. This has been achieved by growing a polyethylenedioxythiophene polymer network in the presence of CNT and melamine followed by its pyrolysis under an inert atmosphere. The catalyst formed at 900 degrees C (PMCNT-900) displays 0.94 V onset potential for ORR under acidic electrolyte conditions, which corresponds to 60 mV overpotential compared to its 40 wt % Pt/C counterpart. Interestingly, in single cell demonstration of Nafion-based PEMFC with PMCNT-900 as the cathode catalyst, the system delivered a maximum power density (PD) of 500 and 275 mW/cm(2) at 60 degrees C under H-2-O-2 and H-2-air feed conditions, respectively. On the other hand, in a single cell test in the anion exchange membrane fuel cell (AEMFC) mode, a maximum power density of 65 mW/cm(2) at 50 degrees C could be achieved with the same cathode catalyst, which is a comparable value obtained while employing Pt/C as the cathode. These results, thus, infer to the efficiency of the catalyst to facilitate ORR under the extreme pH conditions, and particularly its performance under acidic condition reveals its prospect as a potential Pt-free electrocatalyst to serve in the Nafion-based systems.

10acarbon nanotube10aelectrocatalyst10afuel cell10aoxygen reduction reaction10aPt-free ORR1 aBhange, Siddheshwar, N.1 aSoni, Roby1 aSingla, Gourav1 aAjithkumar, T., G.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/fenxfesx-anchored-carbon-sheet-carbon-nanotube-composite-electrocatalysts-oxygen-reduction01617nas a2200265 4500008004100000022001400041245010300055210006900158260000800227300001400235490000600249520073700255653001800992653002001010653001501030653000901045653003001054653000901084100002301093700002101116700002201137700003601159700002501195856013101220 2020 eng d a2574-096200aTweaking palladium electronic structure to attain oxygen reduction activity superior to platinum/C0 aTweaking palladium electronic structure to attain oxygen reducti cJUL a6127-61320 v33 a

Enhancing oxygen reduction (ORR) activity through alloying is crucial to improve the performance of a fuel-cell catalysts. In this work, we have studied the alloying effects of 4f rare-earth (RE) metals with palladium. The modified catalyst exhibits better activity (E-onset = 1 V and E-1/2 = 0.88 V) and higher selectivity toward H2O (similar to 97%) compared to the state-of-the-art catalysts due to complete dissociation of O-2. Hirshfeld charge analysis and 2D-electron localization function reveal improved adsorbate-adsorbent interaction on the catalyst surface. This work paves a strategy to design highly selective non-Pt-based catalysts for the ORR by controlling electronic structures and surface oxide formation.

10ad-band center10aDFT calculation10adurability10aEuPd10aoxygen reduction reaction10aYbPd1 aSarma, Saurav, Ch.1 aKaja, Sai, Manoj1 aMishra, Vidyanshu1 aVinod, Chathakudath, Prabhakara1 aPeter, Sebastian, C. uhttps://library.ncl.res.in/content/tweaking-palladium-electronic-structure-attain-oxygen-reduction-activity-superior-platinumc02844nas a2200241 4500008004100000022001400041245017400055210006900229260000800298300001400306490000600320520196200326653001602288653002002304653001402324653003002338653001902368100001802387700002802405700001502433700002402448856013002472 2020 eng d a2574-096200aWO3 nanorods bearing interconnected Pt nanoparticle units as an activity-modulated and corrosion-resistant carbon-free system for polymer electrolyte membrane fuel cells0 aWO3 nanorods bearing interconnected Pt nanoparticle units as an  cFEB a1908-19210 v33 a

Commercial platinum-supported carbon (Pt/C) catalyst is the most widely used oxygen reduction reaction (ORR) electrocatalyst in polymer electrolyte membrane fuel cells (PEMFCs). However, carbon oxidation in Pt/C during the operation of PEMFCs poses serious issues, particularly in meeting long-term durability of the cells. Although carbon-free Pt-based catalysts are considered to be the best alternatives, the single-cell performances reported for many such systems are found to be inferior to that of the carbon-based systems. As a practical way to realize a carbon-free electrocatalyst, we have developed a system by dispersing an interconnected Pt nanoparticle network on the nanorods of tungsten oxide (WO3). Uniform dispersion of the WO3 nanorods by fine and more or less interconnected Pt nanoparticles (20 wt %) is a key feature of the electrocatalyst. This has helped the system to achieve an intrinsic ORR characteristics which is very similar to that of Pt/C, as reflected from the comparative analysis of the onset potential, half-wave potential, limiting current density, and the number of electrons transferred in the ORR process. Pt/WO3 also shows better stability under start-stop accelerated potential cycling after 10 000 cycles, compared to Pt/C. The relative decrement in the electrochemically active surface area (ECSA) for Pt/WO3 nanorods was negligible, compared to the similar to 26% decrement registered by Pt/C under the identical testing conditions. Finally, a system-level validation in a single-cell model of PEMFC by fabricating a membrane electrode assembly (MEA) with Pt/WO3 as both the anode and cathode catalyst delivered comparable output power density as that of a similar system fabricated by using Pt/C. ECSA comparison in MEA shows the potential use of Pt/WO3-400 as the catalyst for the fuel cells, since it is exhibiting an ECSA value that is 3.4 greater than that of Pt/C at a Pt loading of 0.5 mg cm(-2).

10aCarbon-free10aelectrocatalyst10afuel cell10aoxygen reduction reaction10atungsten oxide1 aKumar, Sachin1 aBhange, Siddheshwar, N.1 aSoni, Roby1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/wo3-nanorods-bearing-interconnected-pt-nanoparticle-units-activity-modulated-and-corrosion02183nas a2200253 4500008004100000022001400041245012000055210006900175260000800244300001200252490000600264520129000270653002101560653001501581653001301596653003001609100002801639700002701667700002901694700002901723700002501752700002401777856012801801 2021 eng d a2366-748600aIn situ preparation of ionomer as a tool for triple-phase boundary enhancement in 3D graphene supported Pt catalyst0 aIn situ preparation of ionomer as a tool for triplephase boundar cJAN a20001250 v53 a

For improving the performance of platinum electrocatalysts in polymer electrolyte membrane fuel cells (PEMFCs), it is important to enhance the Pt utilization level in the catalyst systems. A high performing electrocatalyst (Pt/3DNG) is developed for PEMFC applications by using nitrogen-doped 3D graphene (3DNG) as the support material and an in situ grafted active ``triple-phase boundary'' to more precisely control the formation of the proton conducting ionomer interface at the active sites. Considering the 3D morphology of the system, during the electrode fabrication for realistic single-cell evaluation, the concept of in situ generation of the proton conducting-ionomer based ``active triple-phase boundary'' is introduced, which could potentially replace the conventional method of using Nafion ionomer for the electrode preparation. The monomers owing to their small-size can access the pores and inner regions of the 3DNG support, which on UV-curing, undergo polymerization and transform into an ionomer with an extended interfacial network into the nanoregimes of 3DNG. Single cell evaluation of the membrane electrode assembly in a high-temperature PEMFC by using phosphoric acid doped polybenzimidazole membrane demonstrates the utility of the present strategy.

10aelectrocatalysts10afuel cells10agraphene10aoxygen reduction reaction1 aGangadharan, Pranav, K.1 aVijayakumar, Vidyanand1 aNediyirakkal, Shijil, A.1 aFernandez, Roshni, Tresa1 aSiddharthan, Adhrika1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/situ-preparation-ionomer-tool-triple-phase-boundary-enhancement-3d-graphene-supported-pt02158nas a2200229 4500008004100000022001400041245012900055210006900184260000800253300001100261490000700272520129700279653003401576653001901610653003701629653003001666653003001696653001601726100002901742700002701771856013001798 2021 eng d a2452-262700aMolecularly engineered graphene oxide anchored metal organic assembly: an active site economic bi-functional electrocatalyst0 aMolecularly engineered graphene oxide anchored metal organic ass cSEP a1002690 v293 aLow-temperature fuel cells are the most promising sustainable energy technology as they use hydrogen, an environmentally clean fuel. However, the sluggish kinetics of oxygen electrochemistry, a chronic issue, is holding them from commercialization. Herein, we address this issue through a molecular level design of a Graphene oxide anchored Metal Organic Molecular Assembly (G-MOMA) based catalyst. This non-precious metal catalyst consists of Ni and Fe ions ligated by graphene oxide supported terpyridine, a unique molecular assembly design that maximizes the utilization of active metal centers. This G-MOMA catalyst brings down an over potential (240 mV) for oxygen evolution reaction (OER) as close as that of the bench mark catalyst Ru/C with an impressive Tafel slope of 58 mV/dec and a cyclic stability of >30,000 cycles. G-MOMA excels in oxygen reduction reaction (ORR) too with an onset at 0.88 V (vs RHE). The remarkably stable G-MOMA catalyst surprises with an excellent bi-functionality towards both OER and ORR with an overall potential difference of mere 0.77 V, which is 180 mV and 70 mV lesser than the standard Pt/C and Ru/C catalysts, respectively. The G-MOMA catalyst is well in the activity range of the state-of-art bi-functional catalysts and yet cheaper by many folds.10aBi-functional electrocatalyst10agraphene oxide10aMetal organic molecular assembly10aOxygen Evolution Reaction10aoxygen reduction reaction10aterpyridine1 aJhajharia, Suman, Kumari1 aSelvaraj, Kaliaperumal uhttps://library.ncl.res.in/content/molecularly-engineered-graphene-oxide-anchored-metal-organic-assembly-active-site-economic02644nas a2200265 4500008004100000245012200041210006900163260000900232300001400241490000600255520168400261653002901945653003401974653002102008653003002029653002502059653003002084100001902114700002302133700002802156700002402184700002402208700002102232856012502253 2021 eng d00aSeed-mediated growth of Pt on high-index faceted Au nanocrystals: the ag lining and implications for electrocatalysis0 aSeedmediated growth of Pt on highindex faceted Au nanocrystals t cSEP  a9155-91660 v43 aBimetallic Au@Pt nanocrystals (NCs) offer a unique combination of plasmonic and catalytic properties and are a growing field of research. Herein, we report an unusual observation in the behavior of silver ions (Ag+) which was found to play a dominant role in dictating the Pt deposition in a seed-mediated growth method. `While the literature is replete with various instances of Ag-assisted Pt deposition whereby higher concentration of Ag+ translates into a thicker Pt shell, in the present study, contradictory observations were made. In the presence of lower amounts of Ag+, thick Pt shells were visualized, while at higher concentrations of Ag+, the extent of Pt deposition via the galvanic replacement reaction was reduced. Additionally, the presence of Ag was deemed necessary for the Pt deposition to take place, either in the form of an underpotential deposition layer on the Au NCs or by introducing Ag+ in the growth solution. We have demonstrated our findings on two different Au NCs enclosed with high-index facets, concave cuboid, and elongated tetrahexahedra, which mirror similar observations and provide generality to our claim. To the best of our knowledge, the time required for Pt deposition on the Au core in the present work is the least among the reported seed-mediated routes. Furthermore, this work, besides presenting a facile and general route for the amalgamation of catalytic and plasmonic properties in hybrid Pt-Au NCs, sheds light on the mechanistic aspects of Ag-assisted wet-chemical generation of bimetallic Au@Pt NCs. The overall electrocatalytic performance of our Au@Pt NCs toward the oxygen reduction reaction was realized to be impressive.10abimetallic nanostructure10agalvanic replacement reaction10ahigh-index facet10aoxygen reduction reaction10aseed-mediated growth10aunderpotential deposition1 aRoy, Debashree1 aRajendra, Ranguwar1 aGangadharan, Pranav, K.1 aPandikassala, Ajmal1 aKurungot, Sreekumar1 aBallav, Nirmalya uhttps://library.ncl.res.in/content/seed-mediated-growth-pt-high-index-faceted-au-nanocrystals-ag-lining-and-implications02706nas a2200265 4500008004100000022001400041245013400055210006900189260000900258300001400267490000700281520178300288653001802071653002002089653001402109653002102123653001702144653002002161653002202181653003002203100002802233700002402261700002402285856013102309 2021 eng d a1944-824400aToward pH independent oxygen reduction reaction by polydopamine derived 3D interconnected, iron carbide embedded graphitic carbon0 aToward pH independent oxygen reduction reaction by polydopamine  cFEB  a8147-81580 v133 a

Recent advancements on the development of nonprecious electrocatalysts with iron (Fe) incorporated active centers have generated confidence on realizing cost-effective proton exchange membrane fuel cells (PEMFCs). However, most of these catalysts that emerged as a substitution for the platinum supported on carbon (Pt/C) catalysts in oxygen reduction reaction (ORR) are active under basic conditions, and their feasibility in PEMFCs remains as a challenge. In this scenario, this work reports the synthesis of a Pt-free oxygen reduction electrocatalyst prepared by the annealing of polydopamine grown melamine foam. The prepared catalyst has a three-dimensional (3D) interconnected bilayer network structure possessing the carbon nitride backbone wrapped by graphitic carbon layer bearing iron carbides and nitrides as the active centers (3DFePDC). Interestingly, the 3D-FePDC catalyst displayed an ORR activity both under acidic and basic conditions. Whereas the ORR performance of 3D-FePDC closely matches that of the commercial Pt/C in the basic medium, it displays only a low overpotential value of 60 mV under acidic conditions compared to its Pt counterpart. The kinetics of ORR on 3DFePDC is found to be similar to the four-electron (4e) reduction pathway displayed by Pt/C. Testing of a PEMFC in a single cell mode by using 3D-FePDC as the cathode catalyst and Nafion membrane delivered a maximum power density of 278 mW cm(-2), which is a promising value expected from a system based on the nonprecious metal cathode. Ultimately, as a cost-effective catalyst that can effectively perform irrespective of the pH conditions, 3D-FePDC offers significant prospects in the areas like fuel cells and metal-air batteries which work in acidic and/or basic conditions.

10aacidic medium10aelectrocatalyst10afuel cell10agraphitic carbon10aIron carbide10anitrogen doping10anonprecious metal10aoxygen reduction reaction1 aGangadharan, Pranav, K.1 aPandikassala, Ajmal1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/toward-ph-independent-oxygen-reduction-reaction-polydopamine-derived-3d-interconnected-iron02832nas a2200265 4500008004100000022001400041245012000055210006900175260000900244300001400253490000600267520190400273653002502177653001802202653001702220653003102237653003002268653002102298100002102319700002302340700003002363700001702393700002402410856013202434 2021 eng d a2574-096200aZinc-air batteries catalyzed using Co3O4 nanorod-supported N-doped entangled graphene for oxygen reduction reaction0 aZincair batteries catalyzed using Co3O4 nanorodsupported Ndoped  cMAY  a4570-45800 v43 a

The work reported here deals with the development of an efficient non-platinum electrocatalyst for electrochemical oxygen reduction reaction (ORR) through a sequential pathway involving hydrothermal treatment followed by freeze-drying to build the desired structural architecture of the catalyst. The designed catalyst (Co3O4/nitrogen-doped entangled porous 3D graphene (NEGF)), which contains Co3O4 nanorods anchored on the surface of three-dimensional (3D)-structured N-doped graphene, was found to display higher ORR activity during single-electrode testing and demonstrate a Zn-air battery (ZAB) system. Under the hydrothermal treatment at 180 degrees C, in the presence of ammonia, nitrogen was doped into the carbon framework of graphene, which subsequently formed a self-assembled entangled 3D structure of graphene after freeze-drying. The hydrothermal treatment and freeze-drying processes were found to play vital roles in tuning the morphological and structural features of the catalyst. The doped nitrogen, apart from its favorable contribution toward ORR, helped facilitate efficient dispersion of oxide nanorods on graphene. Co3O4/NEGF displayed remarkable ORR activity in 0.1 M KOH solution, as evident from the 60 mV onset potential shift compared to the state-of-the-art Pt/C catalyst and the Tafel slope value of 74 mV dec(-1) vs 68 mV dec(-1) for Pt/C. The ZAB fabricated by employing Co3O4/NEGF as the cathode catalyst was found to be an efficient competitor for the system based on the Pt/C cathode. This high performance has been credited to the controlled interplay of the governing factors such as the interfacial interactions leading to the efficient dispersion of metal oxide nanorods, increased catalyst surface area, the cooperative effect arising from the defects present in the N-doped porous 3D graphene, and the synergetic interactions operating in the system.

10acobalt-oxide nanorod10afreeze-drying10ahydrothermal10aN-doped entangled graphene10aoxygen reduction reaction10azinc-air battery1 aManna, Narugopal1 aSingh, Santosh, K.1 aKharabe, Geeta, Pandurang1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/zinc-air-batteries-catalyzed-using-co3o4-nanorod-supported-n-doped-entangled-graphene-oxygen02327nas a2200229 4500008004100000022001400041245016800055210006900223260000800292490000700300520143400307653003201741653003001773653002301803100001801826700001701844700002701861700004001888700001701928700002401945856012801969 2022 eng d a2194-428800aInfluence of ice templating on oxygen reduction catalytic activity of metal-free heteroatom-doped mesoporous carbon derived from polypyrrole for zinc-air batteries0 aInfluence of ice templating on oxygen reduction catalytic activi cDEC0 v103 a

The development of highly active, cost-effective, and durable, noble metal-free oxygen reduction electrocatalysts is inevitable for the full-fledged implementation of fuel cells and zinc-air batteries. This work reports the synthesis of heteroatom (N, P, S)-doped metal-free mesoporous carbon-based electrocatalyst derived from polypyrrole by combining the ice templating, freeze-drying, and carbonization processes. The correlation between the structure and electrochemical activity of the polypyrrole-derived carbon-based electrocatalyst in the presence and absence of ice templating is investigated. The optimized electrocatalyst, aided by the ice-templating and freeze-drying step, shows an onset and half-wave potential (E-1/2) of 0.94 and 0.78 V vs reversible hydrogen electrode, respectively, in an alkaline electrolyte (0.1 m KOH). Later, the application of the optimized electrocatalyst is demonstrated in a primary zinc-air battery (ZAB) cell. The results prove that the ZAB device performance based on the homemade catalyst is on par with that of the state-of-the-art Pt/C cathode. The catalyst performance is correlated with the heteroatom doping and the enhanced porosity of the sample benefitted from ice templating. Ultimately, this work depicts a facile and rational synthesis of a truly metal-free electrocatalyst for the primary ZABs that can be a potential replacement for state-of-the-art systems.

10ametal-free electrocatalysts10aoxygen reduction reaction10azinc-air batteries1 aKurian, Maria1 aGhosh, Meena1 aVijayakumar, Vidyanand1 aPuthiyaveetil, Priyanka, Pandinhare1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/influence-ice-templating-oxygen-reduction-catalytic-activity-metal-free-heteroatom-doped02272nas a2200277 4500008004100000022001400041245014400055210006900199260000800268300001100276490000800287520127700295653002101572653002101593653003001614653003001644653001501674653002701689100002901716700002101745700002201766700002701788700002701815700002201842856013001864 2022 eng d a0169-433200aSurface alteration driven bi-functional catalytic activity of alkali niobate-N doped graphene composite for exalted oxygen electrochemistry0 aSurface alteration driven bifunctional catalytic activity of alk cAPR a1521600 v5803 aIn this work, we establish that surface reconstruction, oxygen vacancies —specifically those located on the catalyst surface, and high crystallinity can be effective in tuning the catalytic activity of perovskite oxides. We report a high-performance electrocatalyst with an orthorhombic perovskite structure (NaNbO3), having an anisotropic surface layer and high crystallinity that exhibits superior activity and durability for the bi-functional oxygen electrochemistry compared to that of a similar perovskite composition with an isotropic surface layer and low crystallinity. The improvement in the electrocatalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is mainly attributed to the formation of an easy diffusion path on the surface layer due to the ionic movements, enhanced intrinsic activity of the catalytic sites resulting from the higher crystallinity, high oxygen vacancies and a large electrochemically active surface area. The sole key parameter in achieving all the acquired characteristics is the annealing temperature. We believe that the straightforward method of bringing the desired combination of properties by just tweaking the annealing temperature is handy and energy-efficient, and hence easily adoptable.10aBi-functionality10aN-doped graphene10aOxygen Evolution Reaction10aoxygen reduction reaction10aperovskite10aSurface reconstruction1 aJhajharia, Suman, Kumari1 aGupta, Shashaank1 aManappadan, Zinoy1 aSelvaraj, Kaliaperumal1 aPadmanabhan, Myoor, K.1 aMahajan, Roop, L. uhttps://library.ncl.res.in/content/surface-alteration-driven-bi-functional-catalytic-activity-alkali-niobate-n-doped-graphene02076nas a2200277 4500008004100000022001400041245012100055210006900176260000800245300001100253490000800264520114900272653001001421653001401431653002701445653001601472653003001488100002901518700001801547700002101565700002701586700002001613700002401633700001701657856012401674 2022 eng d a0144-861700aTailored synthesis of ultra-stable Au@Pd nanoflowers with enhanced catalytic properties using cellulose nanocrystals0 aTailored synthesis of ultrastable AuPd nanoflowers with enhanced cSEP a1197230 v2923 a

A green strategy for the synthesis of bimetallic core-shell Au@Pd nanoflowers (NFs) employing banana pseudostem-derived TEMPO-oxidized cellulose nanocrystals (TCNC) as both capping and shape-directing agent via seed-mediated method is presented. Flower-like nanostructures of Au@Pd bound to TEMPO-oxidized cellulose nanocrystals (TCNC-Au@Pd) were decorated on amino-functionalized graphene (NH2-RGO) without losing their unique structure, allowing them to be deployed as an efficient, reusable and a green alternative heterogeneous catalyst. The decisive role of TCNC in the structural metamorphosis of nanoparticle morphology were inferred from the structural and morphology analyses. According to our study, the presence of -OH rich TCNC appears to play a pivotal role in the structured evolution of intricate nanostructure morphology. The feasibility of the bio-supported catalyst has been investigated in two concurrently prevalent model catalytic reactions, namely the oxygen reduction reaction (ORR) and the reduction of 4-nitrophenol, the best model reactions in fuel cell and industrial catalytic applications, respectively.

10aAu@Pd10acatalysis10aCellulose nanocrystals10aNanoflowers10aoxygen reduction reaction1 aHakkeem, Hasna, M. Abdul1 aBabu, Aswathy1 aShilpa, Nagaraju1 aVenugopal, Adithya, A.1 aMohamed, A., P.1 aKurungot, Sreekumar1 aPillai, Saju uhttps://library.ncl.res.in/content/tailored-synthesis-ultra-stable-aupd-nanoflowers-enhanced-catalytic-properties-using01783nas a2200229 4500008004100000245010400041210006900145260000800214300001500222490000600237520097200243653001901215653001601234653003501250653002601285653003001311100002201341700002401363700002401387700001801411856012401429 2022 eng d00aTuning of oxygen reduction pathways through structural variation in transition metal-doped Ba2In2O50 aTuning of oxygen reduction pathways through structural variation cJAN ae2021011630 v93 aAbstract Oxygen reduction reaction (ORR) can take place either through a two-electron pathway to form H2O2 or through a four-electron pathway to form H2O. Both the reactions are important in the respective fields, viz., H2O2 production as well as fuel cell technology, and rational design of catalysts is mandatory to acquire high energy efficiency in both cases. Here, we report the structure-electrochemical property correlation of a series of perovskite related brownmillerite compounds, Ba2In0.75M0.25O5 (M=Mn/Fe/Co/Ni/Cu), synthesized by solid-state method. On transition metal doping, octahedral distortions were observed, and the highly disordered material tends to follow the 4e transfer mechanism. More symmetrical structures followed the 2e pathway to form H2O2 as the product with high peroxide selectivity. The distortion in the octahedral arrangement can be a descriptor to finetune the selectivity of the catalysts towards the 2e and 4e pathways of ORR.10abrownmillerite10aDescriptors10aElectrochemical H2O2 synthesis10aOctahedral distortion10aoxygen reduction reaction1 aThundiyil, Shibin1 aPandikassala, Ajmal1 aKurungot, Sreekumar1 aDevi, Nandini uhttps://library.ncl.res.in/content/tuning-oxygen-reduction-pathways-through-structural-variation-transition-metal-doped03207nas a2200277 4500008004100000022001400041245015700055210006900212260000900281300001300290490000700303520218400310653003002494653002702524653002702551653003102578653003002609653003002639100002102669700002202690700002902712700002102741700001702762700002002779856013002799 2023 eng d a0161-494000aProgressions in cathodic catalysts for oxygen reduction and hydrogen evolution in bioelectrochemical systems: Molybdenum as the next-generation catalyst0 aProgressions in cathodic catalysts for oxygen reduction and hydr cJUL  a986-10780 v653 a

Oxygen reduction reactions (ORRs) are unanimously a key factor of system performances in bioelectrochemical systems (BESs), low-temperature fuel cells, and generally in several electrochemical platforms. Platinum (Pt)-based catalyst is the finest electrocatalyst for ORR in BESs; however, it is constrained by its low abundance, high price, and poor catalytic durability in an electrochemical setup for cathodic reaction kinetics. In recent years, significant efforts in trimming the metal-based catalyst up to nanoscale to cater high performance of ORR have been explored. Still, there are many opportunities to improve catalyst performance at cathode through proper selection of an efficient low-cost metal-based ORR catalyst. Molybdenum (Mo) with its multi-dimensional form as 2D and 3D layers and synergistic combination with other non-metals offers prospects of extraordinary performance as low-cost metal-based ORR catalyst over the Pt in delivering enhanced ORR potential. The present review throws light on current requirements of a sturdier catalyst material and thus provides a comprehensive review on the continuing efforts in exploring the possibility of Mo as a low-cost metal-based ORR catalyst. This literature analysis would enlighten the significance of ORR in BESs, followed by the electrochemistry of Mo-based cathodic catalyst, its underlying mechanism and performance limiting factors in the operation of ORR. Moreover, the extensive and systematic acumen in the context of Mo-based catalytic formulations for increased ORR potentials including nano-composite Mo-cathode catalyst; development of Mo-catalyst with varied configurations; carbon-supported Mo-catalyst; morphological changes; surface area modifications; and Mo-coupling with other transition metal and its derivatives were discussed in great detail to provide prospective application of Mo-based catalyst. Lastly, numerous opportunities and projections for future research in fabrication, juxtaposition, and implementation of Mo-based cathodic catalysts and consequent recommendations were discussed as conclusive remarks for bringing out the state-of-the-art review on this subject.

10aBioelectrochemical system10acatalytic formulations10aH-2-evolution reaction10aMo-based cathodic catalyst10amultifunctional catalysts10aoxygen reduction reaction1 aMishra, Puranjan1 aSudarsanam, Putla1 aMahapatra, Durga, Madhab1 aElmekawy, Ahamad1 aPant, Deepak1 aSingh, Lakhveer uhttps://library.ncl.res.in/content/progressions-cathodic-catalysts-oxygen-reduction-and-hydrogen-evolution-bioelectrochemical02156nas a2200229 4500008004100000022001400041245014800055210006900203260000800272490000600280520131300286653003301599653001501632653003001647653002401677100001801701700002001719700002401739700001501763700002401778856012401802 2023 eng d a2366-748600aPt-anchored-zirconium phosphate nanoplates as high-durable carbon-free oxygen reduction reaction electrocatalyst for PEM fuel cell applications0 aPtanchoredzirconium phosphate nanoplates as highdurable carbonfr cFEB0 v73 a

Commercially available platinum-supported carbon (Pt/C) catalysts are the most widely used oxygen reduction reaction (ORR) electrocatalysts in polymer electrolyte membrane fuel cells (PEMFCs). However, inadequate active triple-phase boundary formation and carbon oxidation in Pt/C during PEMFC operation shorten its lifetime and efficiency. In this direction, a new class of carbon-free electrocatalysts for ORR is prepared by dispersing Pt nanoparticles on ZrP (Zirconium phosphates) nanoplates. In one case (ZrP@Pt), the Pt nanoparticles are found to be closely distributed and completely covering the ZrP nanoplates, whereas in the second case (Pt/ZrP), the Pt nanoparticles selectively restrict dispersion along the edges of the support. ZrP as the support displays an intrinsic proton conductivity of approximate to 0.5 x 10(-4) S cm(-1) at 70 degrees C, with an activation energy (E-a) of 0.19 eV. Pt/ZrP shows better durability after 3000 start-stop cycles. The mass activity of Pt/ZrP is increased by 4.6 times compared to Pt/C, which exhibits a loss in mass activity by 1.37 times. The single-cell level validation of ZrP@Pt, Pt/ZrP, and Pt/C as the electrocatalysts in PEMFC at an operating potential of 0.60 V shows the achievable current densities of 0.600, 0.890, and 0.890 A cm(-2).

10acarbon-free electrocatalysts10afuel cells10aoxygen reduction reaction10azirconium phosphate1 aKumar, Sachin1 aYoyakki, Athira1 aPandikassala, Ajmal1 aSoni, Roby1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/pt-anchored-zirconium-phosphate-nanoplates-high-durable-carbon-free-oxygen-reduction02683nas a2200217 4500008004100000022001400041245012900055210006900184260000800253490000600261520186200267653003002129653003002159653004302189100002402232700001802256700002802274700001702302700002402319856012202343 2024 eng d a2366-748600aAdvanced 3D network of N-doped graphitic carbon with FeNi alloy embedding for high-performance rechargeable Zn-air batteries0 aAdvanced 3D network of Ndoped graphitic carbon with FeNi alloy e cJUL0 v83 a

Despite the significant progress in Zn-air batteries (ZABs), their widespread use in the rechargeable sector is hindered due to the scarcity of efficient bifunctional oxygen catalysts that can catalyze both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). To address this, an ORR/OER bifunctional electrocatalyst is designed with ultrafine alloyed FeNi nanoparticles encapsulated in a 3D interconnected N- doped carbon network structure, featuring a carbon nitride backbone enclosed in graphitic carbon. The FeNi electrocatalyst (3DFeNiPDC) showed good bifunctional activity toward both ORR and OER in the basic medium with a low overpotential value of 30 mV for ORR and 6 mV for OER compared to its state-of-the-art counterparts Pt/C, and RuO2, respectively. Utilizing 3DFeNiPDC in a rechargeable Zn-air battery (RZAB) yields an open circuit voltage (OCV) of 1.35 V, a maximum power density of 232 mW cm-2, and an energy density of 707 W h kg-1. Additionally, a flexible RZAB employing 3DFeNiPDC demonstrates an OCV of 1.4 V with various bending angles. These finding suggest 3DFeNiPDC as a viable alternative to noble metal-based RZABs, offering superior bifunctional electrocatalytic activity and stability, particularly with its enhanced air-breathing properties facilitating improved operability under practical conditions. The bifunctional electrocatalytic activity of FeNi alloy nanoparticles embedded in a 3D- interconnected N-doped graphitic carbon (3DFeNiPDC) for both oxygen reduction and oxygen evolution is studied. The 3D architecture and core-shell characteristics of FeNi alloy nanoparticles provide better activity and stability for oxygen electrocatalysis. The electrocatalytic activity of 3DFeNiPDC has been exploited for liquid-state and solid-state flexible rechargeable zinc-air batteries. image

10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable flexible zinc-air battery1 aPandikassala, Ajmal1 aKurian, Maria1 aGangadharan, Pranav, K.1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/advanced-3d-network-n-doped-graphitic-carbon-feni-alloy-embedding-high-performance03376nas a2200337 4500008004100000022001400041245023000055210006900285260000800354490000700362520209900369653000702468653002602475653001402501653002702515653001802542653003002560653003002590653003402620653003402654100003002688700002002718700003302738700001802771700002702789700002002816700001802836700003602854700002402890856012402914 2024 eng d a1613-681000aAluminium, nitrogen-dual-doped reduced graphene oxide Co-existing with cobalt-encapsulated graphitic carbon nanotube as an activity modulated electrocatalyst for oxygen electrocatalyst for oxygen electrochemistry applications0 aAluminium nitrogendualdoped reduced graphene oxide Coexisting wi cAUG0 v203 a

There is a rising need to create high-performing, affordable electrocatalysts in the new field of oxygen electrochemistry. Here, a cost-effective, activity-modulated electrocatalyst with the capacity to trigger both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in an alkaline environment is presented. The catalyst (Al, Co/N-rGCNT) is made up of aluminium, nitrogen-dual-doped reduced graphene oxide sheets co-existing with cobalt-encapsulated carbon nanotube units. Based on X-ray Absorption Spectroscopy (XAS) studies, it is established that the superior reaction kinetics in Al, Co/N-rGCNT over their bulk counterparts can be attributed to their electronic regulation. The Al, Co/N-rGCNT performs as a versatile bifunctional electrocatalyst for zinc-air battery (ZAB), delivering an open circuit potential approximate to 1.35 V and peak power density of 106.3 mW cm-2, which are comparable to the system based on Pt/C. The Al, Co/N-rGCNT-based system showed a specific capacity of 737 mAh gZn-1 compared to 696 mAh gZn-1 delivered by the system based on Pt/C. The DFT calculations indicate that the adsorption of Co in the presence of Al doping in NGr improves the electronic properties favoring ORR. Thus, the Al, Co/N-rGCNT-based rechargeable ZAB (RZAB) emerges as a highly viable and affordable option for the development of RZAB for practical applications. This manuscript reports the development of a new bifunctional catalyst that exhibits high activity and stability under practical operating conditions. The catalyst (Al, Co/N-rGCNT) is made up of aluminium, nitrogen-dual-doped reduced graphene oxide sheets co-existing with the in situ formed cobalt-encapsulated CNT units is synthesized by a scalable pyrolysis method in an inert Ar atmosphere. The developed electrocatalyst achieved enhanced the oxygen reduction reaction (ORR) and the oxygen evolution reaction OER activity as a result of the favorable synergistic modulations and the system can serve as a process-friendly air-electrode for rechargeable zinc-air battery (RZAB). image

10aAl10aBifunctional catalyst10aDFT study10aencapsulated structure10aN-dual doping10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable zinc-air battery10aX-ray absorption spectroscopy1 aKharabe, Geeta, Pandurang1 aBarik, Sidharth1 aVeeranmaril, Sudheesh, Kumar1 aNair, Aathira1 aIllathvalappil, Rajith1 aYoyakki, Athira1 aJoshi, Kavita1 aVinod, Chathakudath, Prabhakara1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/aluminium-nitrogen-dual-doped-reduced-graphene-oxide-co-existing-cobalt-encapsulated02589nas a2200325 4500008004100000022001400041245014000055210006900195260000800264490000700272520142200279653002001701653001901721653002801740653002801768653003001796653003901826653001601865653001801881653005001899100002201949700002401971700002701995700002402022700001802046700002602064700001802090700002402108856013102132 2025 eng d a1613-681000aHot injection assisted electronically modulated twin and grain boundary rich sub-2 nm pt3co alloy resistant to phosphate ion for PEMFCs0 aHot injection assisted electronically modulated twin and grain b cMAY0 v213 a

Modulation of the electronic d-band center, structural defects (line defects), and particle size of Pt3Co alloy electrocatalyst have huge significance in elevating its electrochemical oxygen reduction reaction activity. Deviating from traditional high-temperature strategies, the current work focuses on ripening these benefits by implying a simple economically viable hot-injection-assisted modified polyol process. A conclusive control over decrementing particle size starting from 2.7 to 1.3 nm, an increasing degree of strain (twin boundary), and shifting of the d-band center away from the Fermi level are obtained via varying the temperature to which the solution is injected. The catalyst prepared via the injection at 200 degrees C (Pt3Co(1.3 t,g-b)/fVC-200) has delivered an electrochemical surface area of 84 m(2) g(Pt)(-1) with the onset and half-wave potentials of 0.980 and 0.858 V, respectively, versus RHE and a limiting current of -6.0 mA cm(-2) with stability till 20k cycles. In the high-temperature proton exchange membrane fuel cell Pt3Co(1.3 t,g-b)/fVC-200-based cell has outperformed Pt/C rendering 600 mWcm(-2) under H-2-Air compared to 529 mWcm(-2) of Pt/C with 20% lower Pt loading and double the stability due to enhanced resistance toward phosphoric acid for accelerated voltage cycling. A similar enhancement is seen while employing the catalyst for low-temperature fuel cells.

10aelectrocatalyst10agrain boundary10ahot injection synthesis10amodified polyol process10aoxygen reduction reaction10aproton exchange membrane fuel cell10aPt3Co alloy10atwin boundary10avalance band X-ray photoelectron spectroscopy1 aSingh, Mayank, U.1 aJadhav, Swapnil, D.1 aShivankar, Bhavana, R.1 aPandikassala, Ajmal1 aKumar, Yogesh1 aKrishnamurty, Sailaja1 aVinod, C., P.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/hot-injection-assisted-electronically-modulated-twin-and-grain-boundary-rich-sub-2-nm-pt3co02452nas a2200229 4500008004100000022001400041245013900055210006900194260000800263490000600271520157000277653003001847653003001877653004301907100002401950700002701974700002202001700002402023700002002047700002402067856013102091 2025 eng d a2366-748600aPt-based 3D electrocatalyst with process-friendly features for PEMFCs possessing fast activation and improved mass-transfer properties0 aPtbased 3D electrocatalyst with processfriendly features for PEM cAPR0 v93 a

Polymer-electrolyte-membrane fuel cells (PEMFCs) face the challenges like slow oxygen reduction reaction (ORR) kinetics and limited mass transport at high current densities, which affects their performance. The efficient water removal from the cathode is essential to improve oxygen diffusion. Addressing this, a catalyst is presented with platinum (Pt) nanoparticles distributed within a 3D carbon network (Pt/3DPDC) derived from the polydopamine-coated melamine foam. This unique architecture enhances Pt utilization and water management due to its high porosity and ample free spaces, providing a process-friendly feature for the electrode under PEMFC conditions. The pores and accessible texture of the 3D polydopamine derived carbon (3DPDC) framework facilitate ionomer uptake during the electrode fabrication, extending the active triple-phase boundary and improving the membrane electrode assembly (MEA) performance. The high porosity of Pt/3DPDC is mitigated by adding a small amount of commercial fuel cell catalayst (Pt/C), which maintains the effective catalyst number density per unit area by utilizing the excess porosity of the 3DPDC framework. This controlled interplay of the unique catalyst structure and spatially confined distribution of Pt/C within the Pt/3DPDC framework offers fast activation, reduced electrode flooding, and improved current densities across the operating potential window. This carefully engineered catalyst, designed through bottom-up strategies, is a promising electrocatalyst for practical PEMFC applications.

10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable flexible zinc-air battery1 aPandikassala, Ajmal1 aNadumattuvayil, Varsha1 aSingh, Mayank, U.1 aJadhav, Swapnil, D.1 aYoyakki, Athira1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/pt-based-3d-electrocatalyst-process-friendly-features-pemfcs-possessing-fast-activation-and02297nas a2200253 4500008004100000245015700041210006900198260000800267300001100275490000600286520134700292653003301639653003001672653003001702653003401732100001801766700001701784700002401801700002001825700002001845700002601865700002401891856012801915 2026 eng d00aElucidating the oxygen electrocatalytic activity of chromium cobalt spinel oxide supported over the spherical carbon for rechargeable zinc-air batteries0 aElucidating the oxygen electrocatalytic activity of chromium cob cMAY ae703360 v93 a

Cr1.5Co1.5O4 spinel nanoparticles supported over 3D spherical carbon (Cr1.5Co1.5O4/C-800) is synthesized as a bifunctional electrocatalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for rechargeable zinc air battery (RZAB) applications. The incorporation of Cr into the spinel lattice and the decoration of the active material on a 3D spherical carbon support with intrinsic ORR activity and superior electrical conductivity enable uniform distribution of catalytically active sites, thereby improving bifunctional catalytic activity. The DFT studies were conducted to understand the role of the Cr in modulating the catalytic sites of the active material and to elucidate its effect on tuning the Co sites to enhance the activity. Half-cell studies show that Cr incorporation and spherical carbon support synergistically enhanced catalytic activity, with the Cr1.5Co1.5O4/C-800 catalyst demonstrating an onset potential of 0.93 V (70 mV lower than Pt/C) and an E & half; value of 0.70 V for ORR and an overpotential of 0.369 V at 20 mA cm-2 (eta 20) for OER (0.375 V for the RuO2 catalyst). The catalyst's bifunctional activity was validated in an RZAB, where it outperformed the Pt/C-RuO2 benchmark, delivering superior rate capability and stability and achieving a cycling life exceeding 145 h.

10achromium cobalt spinel oxide10aOxygen Evolution Reaction10aoxygen reduction reaction10arechargeable zinc-air battery1 aKurian, Maria1 aAmin, Seerat1 aPandikassala, Ajmal1 aManoj, Malavika1 aVijayan, Jubina1 aKrishnamurty, Sailaja1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/elucidating-oxygen-electrocatalytic-activity-chromium-cobalt-spinel-oxide-supported-over