02005nas 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-porous02277nas 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-nanocomposites02343nas a2200253 4500008004100000022001400041245014800055210006900203260000900272300001600281490000700297520143700304100002301741700001801764700002701782700001601809700002401825700002401849700001801873700003001891700002101921700002001942856012701962 2020 eng d a1144-054600aTemplate assisted synthesis of Ni,N co-doped porous carbon from Ni incorporated ZIF-8 frameworks for electrocatalytic oxygen reduction reaction0 aTemplate assisted synthesis of NiN codoped porous carbon from Ni cJUL  a12343-123540 v443 a

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.

1 aK., Vaishna, Priya1 aThomas, Minju1 aIllathvalappil, Rajith1 aK., Shijina1 aKurungot, Sreekumar1 aNair, Balagopal, N.1 aMohamed, Peer1 aAnilkumar, Gopinathan, M.1 aYamaguchi, Takeo1 aHareesh, U., S. uhttps://library.ncl.res.in/content/template-assisted-synthesis-nin-co-doped-porous-carbon-ni-incorporated-zif-8-frameworks