02139nas a2200253   4500008004100000022001400041245016900055210006900224260000800293300001400301490000600315520119100321653001901512653003001531653002001561653003201581653002801613100002801641700002501669700001801694700002101712700002401733856012801757       2017                        eng d  a2196-021600aNitrogen-doped graphene with a three-dimensional architecture assisted by carbon nitride tetrapods as an efficient metal-free electrocatalyst for hydrogen evolution0 aNitrogendoped graphene with a threedimensional architecture assi  cOCT  a2643-26520 v43 aCurrent polymer membrane-based electrolyzers use Pt as a cathode catalyst for efficient reduction of water. The high cost of Pt-based catalysts forces researchers to develop alternative electrocatalysts. Here, a simple strategy has been proposed to synthesize a metal-free electrocatalyst for the hydrogen evolution reaction (HER) by high-temperature annealing of graphene oxide-coated melamine foam. The prepared catalyst possesses both structural and functional advantages with its three-dimensional (3D) interconnected arms of carbon nitride (CNx) backbone wrapped with nitrogen-doped graphene (N-RGO) sheets (CNx@N-RGO). CNx@N-RGO faces only a 193 mV overpotential to achieve a current density of 10mAcm(-2), which is far superior to the previously reported Pt-free systems. Along with the high exchange current density 34.7 x 10(-6)A cm(-2) and low Tafel slope of 54 mV dec(-1), CNx@N-RGO follows a Volmer-Heyrovsky mechanism for the HER. DFT calculations show that the synergy between CNx and N-RGO facilitates good electrical coupling between the two moieties and provides optimal binding to H+ ions on the catalyst that, in turn, results in efficient reduction of hydrogen ions.10acarbon nitride10aDensity functional theory10aelectrocatalyst10ahydrogen evolution reaction10anitrogen doped graphene1 aGangadharan, Pranav, K.1 aUnni, SreeKuttan, M.1 aKumar, Nandha1 aGhosh, Prasenjit1 aKurungot, Sreekumar  uhttps://library.ncl.res.in/content/nitrogen-doped-graphene-three-dimensional-architecture-assisted-carbon-nitride-tetrapods02706nas 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<p>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.</p>
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-iron