@article { ISI:000227016500007, title = {In situ XPS investigations of Cu1-xNixZnAl-mixed metal oxide catalysts used in the oxidative steam reforming of bio-ethanol}, journal = {Applied Catalysis B - Environmental}, volume = {55}, number = {4}, year = {2005}, month = {FEB}, pages = {287-299}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A series of CuNiZnAl-multicomponent mixed metal oxide catalysts with various Cu/Ni ratios were prepared by the thermal decomposition of Cu1-xNixZnAl-hydrotalcite-like precursors and tested for oxidative steam reforming of bio-ethanol. Dehydrogenation of EtOH to CH3CHO is favored by Cu-rich catalyst. Introduction of Ni leads to C-C bond rupture and producing CO, CO2 and CH4. H-2 yield (selectivity) varied between 2.6-3.0 mol/mol of ethanol converted (50-55\%) for all catalysts at 300 degreesC. The above catalysts were subjected to in situ XPS studies to understand the nature of active species involved in the catalytic reaction. Core level and valence band XPS as well as Auger electron spectroscopy revealed the existence of Cu2+, Ni2+ and Zn2+ ions on calcined materials. Upon in situ reduction at reactions temperatures, the Cu2+ was fully reduced to Cu-0. while Ni2+ and Zn2+ were partially reduced to Ni-0 and Zn-0, respectively. On reduction, the nature of ZnO on Cu-rich catalyst changes from crystalline to amorphous, relatively inert and highly stabilized electronically. Relative concentration of the Ni-0 and Zn-0 increases upon reduction with decreasing Cu-content. Valence band results demonstrated that the overlap between 3d bands of Cu and Ni was marginal on calcined materials, and no overlap due to metallic clusters formation after reduction. Nonetheless, the density of states at Fermi level increases dramatically for Ni-rich catalysts and likely this influences the product selectivity. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {auger electron spectroscopy, Autothermal reforming, Bio-ethanol, copper oxide, fuel cell, Hydrogen, hydrotalcite, mixed metal oxides, nickel oxide, oxidative steam reforming, Steam reforming, XPS}, issn = {0926-3373}, doi = {10.1016/j.apcatb.2004.09.007}, author = {Velu, S. and Suzuki, K. and Vijayaraj, M. and Barman, S. and Gopinath, Chinnakonda S.} } @article { ISI:000243650800011, title = {High-temperature, polymer-graphite hybrid composites for bipolar plates: effect of processing conditions on electrical properties}, journal = {Journal of Power Sources}, volume = {163}, number = {2}, year = {2007}, month = {JAN}, pages = {702-707}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

High-temperature thermoplastic-graphite composites are prepared using polyphenylene sulfide (PPS) and polyether sulfone (PES) containing natural graphite powder. All samples are prepared by high pressure compaction and heating to high temperatures. The effect of a third additional conducting component on the electrical resistance of these composites is studied. A low resistance of the order of 0.1 Omega can be obtained even for a graphite concentration of 50\% by addition of the third component. The effect of a mixing/blending technique on the anisotropy of conductivity is investigated. Solution blending of PES with graphite leads to lower anisotropy values than powder mixing and compression moulding. The samples when exposed continuously to a working temperature of 100 degrees C give a small but significant reduction in electrical resistance. X-ray diffraction studies on composites prepared by different techniques indicate that there is restructuring and crystallite re-orientation of the graphite phase in the samples. A large reduction in the crystallite size is observed for samples prepared by solution blending while re-orientation occurs after heat treatment. The changes in electrical properties can be correlated with these structural transformations in the composites. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {bipolar plates, conducting polymer, fuel cell, graphite composites, hybrid materials, polyether sulfone, polypherylene sulfide}, issn = {0378-7753}, doi = {10.1016/j.jpowsour.2006.08.019}, author = {Radhakrishnan, S. and Ramanujam, B. T. S. and Adhikari, Arindam and Sivaram, S.} } @article { ISI:000306674200026, title = {Disordered brownmillerite Ba2InCeO5+delta with enhanced oxygen reduction activity}, journal = {Chemistry of Materials}, volume = {24}, number = {14}, year = {2012}, month = {JUL}, pages = {2823-2828}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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.

}, keywords = {brownmillerite, fuel cell, oxygen reduction reaction, Rietveld refinement}, issn = {0897-4756}, doi = {10.1021/cm301863x}, author = {Jijil, Chamundi P. and Unni, SreeKuttan M. and Sreekumar, Kurungot and Devi, R. Nandini} } @article { ISI:000364355500053, title = {Carbon nanohorn-derived graphene nanotubes as a platinum-free fuel cell cathode}, journal = {ACS Applied Materials \& Interfaces}, volume = {7}, number = {43}, year = {2015}, month = {NOV}, pages = {24256-24264}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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.

}, keywords = {carbon nanohorns, carbon nanotube, electrocatalyst, fuel cell, oxygen reduction reaction}, issn = {1944-8244}, doi = {10.1021/acsami.5b07802}, author = {Unni, SreeKuttan M. and Illathvalappil, Rajith and Bhange, Siddheshwar N. and Puthenpediakkal, Hasna and Kurungot, Sreekumar} } @article { ISI:000349580800008, title = {Effect of b site coordination environment in the ORR activity in disordered brownmillerites Ba2In2-xCexO5+delta}, journal = {ACS Applied Materials \& Interfaces}, volume = {7}, number = {5}, year = {2015}, month = {FEB}, pages = {3041-3049}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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.

}, keywords = {brownmillerite, fuel cell, oxygen disorder, oxygen reduction reaction, Rietveld refinement}, issn = {1944-8244}, doi = {10.1021/am5087837}, author = {Jijil, Chamundi P. and Bhange, Siddheshwar N. and Kurungot, Sreekumar and Devi, R. Nandini} } @article {44175, title = {Chitosan intercalated metal organic gel as a green precursor of fe entrenched and fe distributed N-doped mesoporous graphitic carbon for oxygen reduction reaction}, journal = {Chemistryselect}, volume = {2}, year = {2017}, month = {SEP}, pages = {8762-8770}, type = {Article}, abstract = {

Herein, we present Metal-Organic Gel intercalated with chitosan, a {\textquoteleft}green{\textquoteright}{\textquoteright} 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.

}, keywords = {electrocatalyst, fuel cell, Metal-Organic-Gel, oxygen reduction reaction}, issn = {2365-6549}, doi = {10.1002/slct.201701416}, author = {Shijina, Kottarathil and Illathvalappil, Rajith and Kurungot, Sreekumar and Nair, Balagopal N. and Mohamed, A. Peer and Yamaguchi, Takeo and Anilkumar, Gopinathan M. and Hareesh, U. S. and Sailaja, G. S.} } @conference {44037, title = {Fault detection and analysis of Kapton film in fuel cells using image processing}, booktitle = {International Conference on Computing, Analytics and Security Trends, CAST 2016}, year = {2017}, month = {28 April 2017}, abstract = {

Fuel cell is one of the best alternatives of fossil energy in the modern scenario. But still there are some shortcomings such as durability and reliability, which block the wide application of fuel cells. To overcome these barriers, fault diagnosis is an efficient solution. This paper proposes a method for finding dimensional accuracies in Kapton films in membrane electrode assemblies (MEA) of fuel cells using image processing tools for offline fault analysis. {\textcopyright} 2016 IEEE.

}, keywords = {Dimensional accuracy, Fault analysis, fault detection, Fossil energy, fuel cell, Gas fuel purification, image analysis, Image processing, Image processing tools, Kapton films, Membrane electrode assemblies, Offline, polyimides}, isbn = {978-150901338-8}, doi = {10.1109/CAST.2016.7915032}, author = {Firdous, R. and Aherrao, S. and Narute, B. and Borkar, V.} } @article {44637, title = {Morphological ensembles of N-doped porous carbon derived from ZIF-8/Fe-graphene nanocomposites: processing and electrocatalytic studies}, journal = {ChemistrySelect}, volume = {3}, year = {2018}, month = {AUG}, pages = {8688-8697}, abstract = {

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.

}, keywords = {electrocatalyst, fuel cell, N- Fe co-doped carbon, oxygen reduction reaction, ZIF-8}, issn = {2365-6549}, doi = {10.1002/slct.201801419}, author = {Thomas, Minju and Illathvalappil, Rajith and Kurungot, Sreekumar and Nair, Balagopal N. and Mohamed, A. Peer and Anilkumar, Gopinathan M. and Yamaguchi, Takeo and Hareesh, U. S.} } @article {45512, title = {Studies on nano composites of SPEEK/ethylene glycol/cellulose nanocrystals as promising proton exchange membranes}, journal = {Electrochimica Acta}, volume = {293}, year = {2019}, month = {JAN }, pages = {260-272}, type = {Article}, abstract = {

The present work deals with fabrication and characterisations of nano-composite membranes composed of sulfonated poly (ether ether ketone) (SPEEK) cross-linked and reinforced with ethylene glycol (EG) and cellulose nanocrystals (CNCs) respectively. The thin films of cross-linked composite membranes were prepared by solvent casting method and further analysed for physicochemical and electrochemical properties to execute their applicability as promising proton exchange membrane (PEM) in fuel cells. The process of cross-linking helps to improve the strength and dimensional stability of bare SPEEK membranes without compromising with conductivity. However, presence of CNCs further improves the strength and provides an effective pathway for the conduction of protons in membranes by interacting through their surface hydroxyl and sulfonic acid groups with ionic moieties of polymer matrix. All prepared composite membranes showed good oxidative and thermal stability along with good proton conductivity. The cross-linked SPEEK membranes with 4 wt\% loading of CNCs possess an appreciable proton conductivity of 0.186 S/cm at 95 degrees C and 95\% RH which is comparable to Nafion 117. From the view point of above studies, the prepared nano-composite can be described as promising proton exchange membrane for fuel cells. (c) 2018 Elsevier Ltd. All rights reserved.

}, keywords = {Cellulose nanocrystals, Cross-linked SPEEK, fuel cell, oxidative stability, proton conductivity}, issn = {0013-4686}, doi = {10.1016/j.electacta.2018.10.029}, author = {Bano, Saleheen and Negi, Yuvraj S. and Illathvalappil, Rajith and Kurungot, Sreekumar and Ramya, K.} } @article {46971, title = {Enhancing thermomechanical and chemical stability of polymer electrolyte membranes using polydopamine coated nanocellulose}, journal = {ACS Applied Energy Materials}, volume = {3}, year = {2020}, month = {FEB}, pages = {1988-1999}, type = {Article}, abstract = {

We report here an approach to enhance the chemical and thermomechanical stability of polymer electrolyte membranes without compromising proton conductivity. Multifunctional polydopamine coated nanocellulose (PNC) was prepared by oxidative polymerization of dopamine on nano cellulose fibers and subsequently incorporated in Nafion by solution blending. PNC had a very significant effect on the thermomechanical properties of Nafion showing up to 200\% improvement in the storage modulus at 90 degrees C. The PNC network also enhanced the dimensional stability of Nafion under constant stress. The 3 wt \% PNC composite membrane showed a drastic reduction in creep compliance of about 39.9\% and 46.5\% in J(max) at 30 degrees and 60 degrees C, respectively. Free radical scavenging properties of polydopamine also helped to significantly enhance the chemical stability of Nafion, which was ascertained by accelerated degradation tests conducted in Fenton{\textquoteright}s reagent at 70 degrees C over 40 days. F-19 CP MAS solid state NMR, FTIR, and tensile tests on the membranes show higher chemical stability of the 3 wt \% PNC composite membrane. The proton conductivity of the 3 wt \% PNC composite membrane at 90 degrees C and 100\% RH (similar to 125 mS/cm) was slightly higher than the Nafion membrane (similar to 94 mS/cm) at similar conditions. The retention of proton conductivity even with lower water uptake could be ascribed to proton hopping through polydopamine coated nanocellulose. Performance of the composite membrane was also evaluated in a single stack fuel cell and found to be better than recast Nafion. The benefits derived by this approach are not restricted to Nafion alone and shall broadly apply to many other polymer membranes.

}, keywords = {cellulose nanofibers, chemical stability, dimensional stability, fuel cell, polydopamine, polymer electrolyte membrane}, issn = {2574-0962}, doi = {10.1021/acsaem.9b02417}, author = {Ram, Farsa and Velayutham, Parthiban and Sahu, Akhila Kumar and Lele, Ashish K. and Shanmuganathan, Kadhiravan} } @article {46911, title = {Fe3+ stabilized 3D cross-linked glycine-melamine formaldehyde networks as precursor for highly efficient oxygen reduction catalyst in alkaline media}, journal = {Materials Letters}, volume = {264}, year = {2020}, month = {APR 1}, pages = {127365}, type = {Article}, abstract = {

Development of inexpensive oxygen reduction electrocatalyst with high activity and durability is very important. Herein, iron carbide encapsulated pod-like graphitic carbon structures were prepared by simple pyrolysis involving Fe-glycine complex integrated melamine-formaldehyde resin precursor. The best catalyst among those studied, Fe-Gly 2 MF-C, possessing high degree of graphitization (I-D /I-G = 0.99) and enhanced specific surface area (205 m(2)/g) exhibited the highest ORR activity with a half-wave potential of 0.80 V in alkaline medium through the four-electron reduction pathway. (C) 2020 Elsevier B.V. All rights reserved.

}, keywords = {fuel cell, Graphitic carbon alloy, Iron carbide, ORR}, issn = {0167-577X}, doi = {10.1016/j.matlet.2020.127365}, author = {Kottarathil, Shijina and Illathvalappil, Rajith and Nisa, S. and Sailaja, G. S. and Mohamed, Peer A. and Nair, Balagopal N. and Gopinathan, Anilkumar M. and Kurungot, Sreekumar and Yamaguchi, Takeo and Hareesh, U. S.} } @article {46940, title = {FeNx/FeSx-anchored carbon sheet-carbon nanotube composite electrocatalysts for oxygen reduction}, journal = {ACS Applied Nano Materials}, volume = {3}, year = {2020}, month = {MAR}, pages = {2234-2245}, type = {Article}, abstract = {

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.

}, keywords = {carbon nanotube, electrocatalyst, fuel cell, oxygen reduction reaction, Pt-free ORR}, issn = {2574-0970}, doi = {10.1021/acsanm.9b02335}, author = {Bhange, Siddheshwar N. and Soni, Roby and Singla, Gourav and Ajithkumar, T. G. and Kurungot, Sreekumar} } @article {46970, title = {WO3 nanorods bearing interconnected Pt nanoparticle units as an activity-modulated and corrosion-resistant carbon-free system for polymer electrolyte membrane fuel cells}, journal = {ACS Applied Energy Materials}, volume = {3}, year = {2020}, month = {FEB}, pages = {1908-1921}, type = {Article}, abstract = {

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).

}, keywords = {Carbon-free, electrocatalyst, fuel cell, oxygen reduction reaction, tungsten oxide}, issn = {2574-0962}, doi = {10.1021/acsaem.9b02333}, author = {Kumar, Sachin and Bhange, Siddheshwar N. and Soni, Roby and Kurungot, Sreekumar} } @article {47055, title = {Toward pH independent oxygen reduction reaction by polydopamine derived 3D interconnected, iron carbide embedded graphitic carbon}, journal = {ACS Applied Materials \& Interfaces}, volume = {13}, year = {2021}, month = {FEB }, pages = {8147-8158}, type = {Article}, abstract = {

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.

}, keywords = {acidic medium, electrocatalyst, fuel cell, graphitic carbon, Iron carbide, nitrogen doping, nonprecious metal, oxygen reduction reaction}, issn = {1944-8244}, doi = {10.1021/acsami.0c18036}, author = {Gangadharan, Pranav K. and Pandikassala, Ajmal and Kurungot, Sreekumar} } @article {47105, title = {Unveiling the roles of lattice strain and descriptor species on pt-like oxygen reduction activity in Pd-Bi catalysts}, journal = {ACS Catalysis}, volume = {11}, year = {2021}, month = {JAN}, pages = {800-808}, type = {Article}, abstract = {

A facile non-template-assisted mechanical ball milling technique was employed to generate a PdBi alloy catalyst. The induced lattice strain upon the milling time caused a shift of the d-band center, thereby enhancing the oxygen reduction reaction (ORR) catalytic activity. Additionally, the Pd-O reduction potential and adsorbed OH coverage used as descriptors stipulated the cause of the enhanced ORR activity upon the increased milling interval. Redox properties of surface Pd are directly correlated with a positive shift in the Pd-O reduction potential and OH surface coverage. Hence, by deconvoluting the lattice strain and the role of the descriptor species we achieved a catalyst system with a specific activity 5.4X higher than that of commercial Pt/C, as well as an improved durability. The experimental observation is well-corroborated by a theoretical simulation done by inducing strain to the system externally.

}, keywords = {charge-transfer, electrocatalysis, fuel cell, Lattice strain, oxygen reduction, Pt-like activity}, issn = {2155-5435}, doi = {10.1021/acscatal.0c03415}, author = {Sarkar, Shreya and Ramarao, S. D. and Das, Tisita and Das, Risov and Vinod, C. P. and Chakraborty, Sudip and Peter, Sebastian C.} }