@article {45636, title = {Graphene oxide sheathed ZIF-8 microcrystals: engineered precursors of nitrogen-doped porous carbon for efficient oxygen reduction reaction (ORR) electrocatalysis}, journal = {ACS Applied Materials \& Interfaces}, volume = {8}, year = {2016}, month = {NOV}, pages = {29373-29382}, type = {Article}, abstract = {

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.

}, keywords = {alkaline fuel cell, graphene oxide, N-doped carbon, oxygen reduction reaction, porous carbon, ZIF-8}, issn = {1944-8244}, doi = {10.1021/acsami.6b06979}, author = {Thomas, Minju and Illathvalappi, Rajith and Kurungot, Sreekumar and Nair, Balagopal N. and Mohamed, Abdul Azeez Peer and Anilkumar, Gopinathan M. and Yamaguchi, Takeo and Hareesh, U. S.} } @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 {46770, title = {Template assisted synthesis of Ni,N co-doped porous carbon from Ni incorporated ZIF-8 frameworks for electrocatalytic oxygen reduction reaction}, journal = {New Journal of Chemistry}, volume = {44}, year = {2020}, month = {JUL }, pages = {12343-12354}, type = {Article}, abstract = {

A heteroatom doped porous carbon electrocatalyst with enhanced oxygen reduction reaction (ORR) performance in alkaline medium was obtained by high temperature treatment of Ni incorporated ZIF-8 frameworks and its composite with g-C(3)N(4)as a supporting matrix template. The morphology and porosity of this heteroatom containing carbon were tuned by varying the Ni : Zn molar ratio in Ni/Zn ZIF-8 and Ni/Zn ZIF-8@g-C(3)N(4)composites. The template aided synthetic strategy using g-C(3)N(4)helped in the controlled decomposition of composites leading to a heteroporous sheet like architecture with increased nitrogen content. The Ni/Zn ZIF-8 sample on heat treatment in the 800-1000 degrees C temperature range led to the formation of Ni,N co-doped porous carbon (Ni-NPC) with Ni-C active sites. The defective sites induced by nickel carbide along with the distributed N atoms on the carbon surface enabled active O(2)adsorption sites. The high surface area, high degree of graphitisation as well as the defects created by well dispersed N and Ni on porous carbon matrices favoured charge separation leading to higher electrochemical ORR activity. The Ni,N co-doped carbon catalyst in alkaline medium exhibited a limiting current density of 5.2 mA cm(-2)with a half-wave potential of 0.76 Vvs.RHE in 0.1 M KOH. The catalyst also showed improved methanol tolerance and better stability compared to the standard Pt/C catalyst.

}, issn = {1144-0546}, doi = {10.1039/d0nj01373k}, author = {Priya K., Vaishna and Thomas, Minju and Illathvalappil, Rajith and K., Shijina and Kurungot, Sreekumar and Nair, Balagopal N. and Mohamed, A. Peer and Anilkumar, Gopinathan M. and Yamaguchi, Takeo and Hareesh, U. S.} }