02901nas 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-nanoparticles01900nas a2200181 4500008004100000022001400041245012300055210006900178260000900247300001400256490000600270520122500276100002101501700002001522700002301542700002401565856012901589 2020 eng d a2516-023000aNiFe layered double hydroxide-decorated N-doped entangled-graphene framework: a robust water oxidation electrocatalyst0 aNiFe layered double hydroxidedecorated Ndoped entangledgraphene  cAPR  a1709-17170 v23 a

Three dimensional (3D) porous carbon materials are highly desirable for electrochemical applications owing to their high surface area and porosity. Uniformly distributed porosity in the 3D architecture of carbon support materials allows reactant molecules to access more electrochemically active centres and simultaneously facilitate removal of the product formed during electrochemical reactions. Herein, we have prepared a nitrogen-doped entangled graphene framework (NEGF), decorated with NiFe-LDH nanostructures by an in situ solvothermal method followed by freeze-drying at high vacuum pressure and low temperature. The freeze-drying method helped to prevent the restacking of the graphene sheets and the formation of a high surface area nitrogen-doped entangled graphene framework (NEGF) supported NiFe-LDHs. The incorporation of the NEGF has significantly reduced the overpotential for the electrochemical oxygen evolution reaction (OER) in 1 M KOH solution. This corresponds to an overpotential reduction from 340 mV for NiFe-LDHs to 290 mV for NiFe-LDH/NEGF to reach the benchmark current density of 10 mA cm(-2). The preparation of the catalyst is conceived through a low-temperature scalable process.

1 aManna, Narugopal1 aAyasha, Nadeema1 aSingh, Santosh, K.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/nife-layered-double-hydroxide-decorated-n-doped-entangled-graphene-framework-robust-water02832nas 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-oxygen02683nas a2200253 4500008004100000022001400041245010100055210006900156260000900225300001400234490000600248520179900254653002602053653003302079653003102112653003302143653001802176100002102194700002302215700001802238700001702256700002402273856013202297 2022 eng d a2574-096200aAir-cathode interface-engineered electrocatalyst for solid-state rechargeable zinc-air batteries0 aAircathode interfaceengineered electrocatalyst for solidstate re cJUL  a8756-87680 v53 a

Solid-state rechargeable zinc-air batteries (ZABs) are gaining interest as a class of portable clean energy technology due to their advantages such as high theoretical energy density, intrinsic safety, and low cost. It is expected that an appropriately triple-phase boundary (TPB) engineered, bifunctional oxygen reaction (OER and ORR) electrocatalyst at the air- electrode of ZABs can redefine the performance characteristics of these systems. To explore this possibility, an electrode material consisting of manganese- cobalt-based bimetallic spinel oxide (MnCo2O4)-supported nitrogen-doped entangled graphene (MnCo2O4/NEGF) with multiple active sites responsible for facilitating both OER and ORR has been prepared. The porous 3D graphitic support significantly affects the bifunctional oxygen reaction kinetics and helps the system display a remarkable catalytic performance. The air electrode consisting of the MnCo2O4/NEGF catalyst coated over the gas diffusion layer (GDL) ensures the effective TPB, and this feature works in favor of the rechargeable ZAB system under the charging and discharging modes. As an important structural and functional attribute of the electrocatalyst, the porosity and nitrogen doping in the 3D conducting support play a decisive aspect in controlling the surface wettability (hydrophilicity/hydrophobicity) of the air electrode. The fabricated solid-state rechargeable ZAB device with the developed electrode displayed a maximum peak power density of 202 mW cm(-2), which is significantly improved as compared to the one based on the Pt/C + RuO2 standard catalyst pair (124 mW cm(-2)). The solid-state device which displayed an initial charge-discharge voltage gap of only 0.7 V at 10 mA cm(-2) showed only a small increment of 86 mV after 50 h.

10aair-cathode interface10abifunctional oxygen catalyst10aN-doped entangled graphene10asolid-state zinc-air battery10aspinel oxides1 aManna, Narugopal1 aSingh, Santosh, K.1 aKurian, Maria1 aTorris, Arun1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/air-cathode-interface-engineered-electrocatalyst-solid-state-rechargeable-zinc-air-batteries02781nas a2200229 4500008004100000022001400041245012800055210006900183260000800252300001600260490000700276520196500283100003002248700002102278700002002299700002302319700001802342700001802360700001802378700002402396856013102420 2022 eng d a2050-748800aPseudo-boehmite AlOOH supported NGr composite-based air electrode for mechanically rechargeable Zn-air battery applications0 aPseudoboehmite AlOOH supported NGr compositebased air electrode  cMAY a10014-100250 v103 a

Both mechanically and electrically rechargeable zinc-air batteries (ZABs) have received much interest due to their high energy density and suitability for mobile and stationary applications. However, their commercialization has been impeded by the lack of robust, low-cost and environmentally benign catalyst materials that can be easily scaled up. In this context, the present work introduces a new type of transition metal-free catalytic material (AlOOH/NGr) by anchoring the pseudo-boehmite phase of aluminium oxyhydroxide (AlOOH) nanosheets over nitrogen-doped graphene (NGr) via a single-step and straightforward hydrothermal process. Furthermore, density functional theory (DFT) based computation demonstrates that the nucleation of AlOOH starts from the N-sites and points towards the strong surface interaction between AlOOH and NGr via doped nitrogen. AlOOH/NGr consisting of thin layered pseudo-boehmite sheets uniformly distributed over NGr has displayed an oxygen reduction reaction onset potential of 0.83 V and a half-wave potential of 0.72 V, along with good catalytic durability in alkaline medium. With this, AlOOH/NGr, when used as an air electrode for fabricating a primary Zn-air battery, the system has exhibited an open circuit voltage of similar to 1.27 V with a flat discharge profile at a current rate of 10 mA cm(-2). The fabricated system delivered a specific capacity of similar to 720 mA h g(-1) and a high power density of 204 mW cm(-2) and is comparable to the counterpart system based on the state-of-the-art Pt/C (20 wt% Pt) cathode. Additionally, the homemade battery was able to maintain its performance after 4 times of mechanical recharging of the battery, which lasted for more than 35 h at a discharge current density of 10 mA cm(-2). Thus, we have uncovered the potential of an earth-abundant metal-based catalytic system for fabricating and demonstrating a robust mechanically rechargeable zinc-air battery.

1 aKharabe, Geeta, Pandurang1 aManna, Narugopal1 aNadeema, Ayasha1 aSingh, Santosh, K.1 aMehta, Shweta1 aNair, Aathira1 aJoshi, Kavita1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/pseudo-boehmite-alooh-supported-ngr-composite-based-air-electrode-mechanically-rechargeable02016nas a2200205 4500008004100000022001400041245018000055210006900235260000800304300001600312490000700328520121400335100001801549700002701567700002101594700002701615700001701642700002401659856012701683 2023 eng d a2050-748800aElectrode|electrolyte interface enhancement in quasi-solid-state zinc-air batteries through an anion conducting polymer electrolyte interlayer by in situ polymerization0 aElectrodeelectrolyte interface enhancement in quasisolidstate zi cJUL a14776-147870 v113 a

This work introduces a novel concept of electrode|electrolyte interface enhancement using an ultraviolet (UV) light-assisted in situ polymerization strategy to improve the performance of quasi-solid-state zinc-air batteries (ZABs). The suitability of the UV polymerization strategy to process a mechanically stable OH- conducting anion exchange polymer electrolyte membrane (AEPEM) reinforced by a glass fiber (GF) separator is also reported. The in situ polymerized ionomer-skin/interlayer (a thin anion-conducting polymer coating over the air-cathode of ZAB) acts as a buffer layer to narrow down the performance gap generally observed between ZABs possessing quasi-solid-state electrolytes and standard liquid electrolytes, respectively. For instance, when combined with the in situ polymerization strategy, a rechargeable ZAB (rZAB) based on an AEPEM-GF composite membrane delivered a high power density of 140 mW cm(-2), higher than that of the one without an in situ polymerized ionomer interlayer (120 mW cm(-2)). Notably, in a flexible rZAB configuration, this new strategy resulted in enhanced rate capability and cycling stability for 14 h at an operating current density of 2 mA cm(-2).

1 aKurian, Maria1 aVijayakumar, Vidyanand1 aManna, Narugopal1 aKanheerampockil, Fayis1 aBhat, Suresh1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/electrodeelectrolyte-interface-enhancement-quasi-solid-state-zinc-air-batteries-through03106nas a2200241 4500008004100000022001400041245014800055210006900203260000900272300001600281490000700297520225700304653002402561653003102585653000802616653001002624653002102634653001602655100002102671700001802692700002402710856013002734 2023 eng d a1944-824400aMicroporous 3D-structured hierarchically entangled graphene-supported Pt3Co alloy catalyst for PEMFC application with process-friendly features0 aMicroporous 3Dstructured hierarchically entangled graphenesuppor cJUN  a28023-280350 v153 a

To improve the oxygen reduction reaction(ORR) performance in aproton-exchange membrane fuel cell (PEMFC) cathode with respect tomass activity and durability, a suitable electrocatalyst design strategyis essentially needed. Here, we have prepared a sub-three nm-sizedplatinum (Pt)-cobalt (Co) alloy (Pt3Co)-supportedN-doped microporous 3D graphene (Pt3Co/pNEGF) by usingthe polyol synthesis method. A microwave-assisted synthesis methodwas employed to prepare the catalyst based on the 3D porous carbonsupport with a large pore volume and dense micro-/mesoporous surfaces.The ORR performance of Pt3Co/pNEGF closely matches withthe state-of-the-art commercial Pt/C catalyst in0.1 M HClO4, with a small overpotential of 10 mV. The 3Dmicroporous structure of the N-doped graphene significantly improvesthe mass transport of the reactant and thus the overall ORR performance.As a result of the lower loading of Pt in Pt3Co/pNEGF ascompared to that in Pt/C, the alloy catalyst achieved 1.5 times highermass activity than Pt/C. After 10,000 cycles, the difference in theelectrochemically active surface area (ECSA) and half-wave potential(E (1/2)) of Pt3Co/pNEGF is foundto be 5 m(2) g(Pt) (-1) (Delta ECSA)and 24 mV (Delta E (1/2)), whereas, forPt/C, these values are 9 m(2) g(Pt) (-1) and 32 mV, respectively. Finally, in a realistic perspective, single-celltesting of a membrane electrode assembly (MEA) was made by sandwichingthe Pt3Co/pNEGF-coated gas diffusion layers as the cathodedisplayed a maximum power density of 800 mW cm(-2) under H-2-O-2 feed conditions with aclear indication of helping the system in the mass-transfer region(i.e., the high current dragging condition). The nature of the I-V polarization shows a progressivelylower slope in this region of the polarization plot compared to asimilar system made from its Pt/C counterpart and a significantlyimproved performance throughout the polarization region in the caseof the system made from the Pt3Co/NEGF catalyst (withoutthe microwave treatment) counterpart. These results validate the betterprocess friendliness of Pt3Co/pNEGF as a PEMFC electrode-specificcatalyst owing to its unique texture with 3D architecture and well-definedporosity with better structural endurance.

10amicrowave synthesis10aN-doped porous 3D graphene10aORR10aPEMFC10apolyol synthesis10aPt3Co alloy1 aManna, Narugopal1 aSingh, Mayank1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/microporous-3d-structured-hierarchically-entangled-graphene-supported-pt3co-alloy-catalyst02247nas a2200301 4500008004100000022001400041245013300055210006900188260000800257300001400265490000600279520122600285653001701511653002201528653002101550653002401571653002101595653002601616100002401642700002601666700002001692700002101712700001801733700001701751700002501768700002301793856012901816 2023 eng d a2574-096200aTheory-directed designing of an intrinsic-activity-modulated metal-doped copper oxide electrode for nitrate to ammonia synthesis0 aTheorydirected designing of an intrinsicactivitymodulated metald cMAY a6111-61190 v63 a

Synthesis of ammonia via electrochemical reduction ofnitrate isone of the most sustainable routes both for environmental protectionas well as energy saving initiatives. However, this process is limitedto the development of high-performance free-standing catalytic electrodeswith improved selectivity and Faradaic efficiency. Herein, we reporttheory-guided designing and fabrication of free-standing non-noblemetal (Mn, Fe, and Co)-doped copper oxide (CuO) electrodes by usinga simple and scalable electrode preparation method. The density functionaltheory (DFT)-based calculations show that the doped-Co sites in theCu surface facilitate the generation and supply of H+ tothe adsorbed NO3 (-) during the reductionprocess; as a result, the Co-CuO catalyst displays higher selectivitytoward nitrate reduction. The Co-doped Cu electrode (Co-CuO)delivers a higher NH3 yield (5492 mu g cm(-2)) at a reduction potential of -0.91 V vs RHE while maintaininga Faradaic efficiency of >95%. The alloying of Co to the coppermetalnot only facilitates the proton donation to the adsorbed reactant(NO3 (-)) but also tunes the Cu d-center,resulting in the active site modulation responsible for the activationof catalysts.

10aActive sites10aammonia synthesis10aelectrocatalysis10aFaradaic efficiency10aHigh selectivity10ametal-doped electrode1 aTyagi, Nitin, Kumar1 aMahapatra, Bikash, K.1 aGhimire, Suvash1 aManna, Narugopal1 aKumar, Deepak1 aKumar, Vijay1 aMukhopadhyay, Kausik1 aSingh, Santosh, K. uhttps://library.ncl.res.in/content/theory-directed-designing-intrinsic-activity-modulated-metal-doped-copper-oxide-electrode01312nas a2200241 4500008004100000022001400041245008900055210006900144260000900213300001400222490000700236520051800243653000600761653002700767653001800794653002100812100002800833700001700861700002500878700002100903700002400924856012200948 2024 eng d a1359-734500aElectrochemically enabled (3+2) cycloaddition of unbiased alkenes and β-dicarbonyls0 aElectrochemically enabled 32 cycloaddition of unbiased alkenes a cMAY  a5836-58390 v603 a

A (3+2) cycloaddition between unbiased alkenes and 1,3-dicarbonyls is accomplished by judicious choice of electrode material and electrocatalyst to access dihydrofuran derivatives. A fluorinated porous carbon electrode with appropriate thickness governs unprecedented reactivity. This methodology eliminates the necessity for any stabilizing group within the alkene substrate. This is a rare example of the annulation of unbiased internal and terminal alkenes with cyclic and acyclic beta-dicarbonyls.

10a110a3-DICARBONYL COMPOUNDS10aDIHYDROFURANS10aFACILE SYNTHESIS1 aSuryawanshi, Sharad, M.1 aSahoo, Suman1 aShaligram, Parth, S.1 aManna, Narugopal1 aSamanta, Ramesh, C. uhttps://library.ncl.res.in/content/electrochemically-enabled-32-cycloaddition-unbiased-alkenes-and-%CE%B2-dicarbonyls01697nas a2200193 4500008004100000022001400041245014800055210006900203260000800272300001500280490000700295520097600302100002101278700001501299700001801314700001901332700002301351856012901374 2025 eng d a2196-021600aHigh-performance polysulfide-trapping lithium sulfur battery cathode: cubic Co3O4 catalyst within a nitrogen-doped entangled graphene framework0 aHighperformance polysulfidetrapping lithium sulfur battery catho cFEB ae2024004880 v123 a

The cycling performance of lithium-sulfur (Li-S) batteries is hampered by polysulfide dissolution which impacts the overall performance of Li-S batteries. Here we report the synthesis and characterization of polysulfide trapping cathode material for Li-S batteries based on Co3O4 nanocubes supported within a nitrogen-doped entangled graphene (Co3O4/NEGF). The highly porous conductive graphene network is shown to facilitate fast electron transport and ion diffusion while the nitrogen dopants and polar Co3O4 offer both abundant active sites for polysulfide conversion while promoting intermediate polysulfide binding. The porous structure allows for high sulfur loading of 76.4 wt % (S@Co3O4/NEGF), while efficiently accommodating volumetric expansion during charge-discharge. The Co3O4/NEGF cathode composite exhibited a high specific capacity of 1143 mAh g-1 at a current density of C/20 and maintained a 79 % reversible capacity after 200 cycles at C/5.

1 aManna, Narugopal1 aSoni, Roby1 aYoung, R., S.1 aJervis, Rhodri1 aMiller, Thomas, S. uhttps://library.ncl.res.in/content/high-performance-polysulfide-trapping-lithium-sulfur-battery-cathode-cubic-co3o4-catalyst02408nas a2200277 4500008004100000022001400041245016800055210006900223260000800292490000600300520146300306653000801769653001801777653001701795653000801812653000801820100001801828700002001846700002401866700003001890700002301920700002101943700001701964700002401981856012502005 2025 eng d a2366-748600aSelf-supported super-hydrophilic interconnected nanospikes and particles of MoS2-Ni3S2/NF with optimum d-band center for anion exchange membrane water electrolyzer0 aSelfsupported superhydrophilic interconnected nanospikes and par cMAR0 v93 a

There is an imperative need for highly efficient electrocatalysts for cost-effective hydrogen production. Herein, a self-supported, hybrid composite as a bifunctional electrocatalyst is introduced. This is achieved by in situ growth of MoS2-Ni3S2 on nickel foam (NF), designated as MoS2-Ni3S2/NF, synthesized by a facile one-step hydrothermal synthesis method. MoS2-Ni3S2/NF exhibits low overpotentials of only 187 and 146 mV for OER and HER, respectively, to achieve a current density of 10 mA cm-2 in 1 M KOH. The practical application of the designed bifunctional electrocatalyst is verified by constructing the MoS2-Ni3S2/NF || MoS2-Ni3S2/NF symmetrical membrane electrode assembly (MEA) of 4 cm2 working area for the anion exchange membrane water electrolyzer. The system shows continuous electrolysis for the monitored 48 h duration. For OER, an optimum d-band center of -1.66 eV for the heterostructure is calculated from the Density Functional Theory (DFT) studies. The factors like the unique structure of the electrocatalyst, enhanced hydrophilicity, improved electrochemically accessible number of sites (ECASs), and optimum d-band center, are expected to be the primary contributors to the system's improved performance. Thus, the present finding unveils a straightforward synthesis approach for creating a stable electrocatalyst for advancing commercial water electrolysis in the realm of renewable electrochemical energy conversion.

10aAEM10ad-band center10aelectrolyzer10aHER10aOER1 aKumar, Yogesh1 aBarik, Sidharth1 aSamudre, Nikhil, S.1 aKharabe, Geeta, Pandurang1 aChauhan, Inderjeet1 aManna, Narugopal1 aBhat, Suresh1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/self-supported-super-hydrophilic-interconnected-nanospikes-and-particles-mos2-ni3s2nf