A systematic investigation of the electrocatalytic Methanol Oxidation Reaction (MOR) was carried out using a model Co:Pt alloy system with different compositions and structural arrangements of the Co and Pt atoms. The structural variations with the same alloy composition included those with disordered arrangement of Co and Pt atoms in a face-centered cubic (fcc) lattice and ordered arrangements in face-centered tetragonal (fct) lattices. Our investigations clearly show that structures with disordered arrangements with Co:Pt atomic ratios near to 1:1 display better electrocatalytic efficiencies even when compared to pure Pt. These experimental findings were then rationalized by means of Density Functional Theory (DFT) calculations. Electronic level signatures in terms of charge transfer and relative shift in the peaks of the d band for surface metal atoms are proposed to be the reasons for the superior catalytic activity of a particular composition over the others. An increase in the number of inequivalent sites for methanol adsorption in disordered systems appears to result in better catalytic performance in comparison with ordered systems.
This study investigates the synthesis of high surface area W 2 N and Co-W-N nitrides by nitridation of various precursors obtained by chemical routes. For the synthesis of W 2 N nitride, WO 3 precursors were obtained by acidifying Na 2 WO 4 ·2H 2 O (acid route) and by thermal decomposition of the tungstate-citrate precursor. The solid-state reactivity, BET surface areas and pore structures of the nitride materials have been investigated in detail. Co-W-N nitride was obtained from CoWO 4 synthesized by co-precipitation. W 2 N and Co-W-N nitrides crystallize in β-W 2 N structure. The single-point BET surface areas were estimated to be 58, 55 and 60 m 2 /g for the β-W 2 N nitride materials synthesized using commercial WO 3 and WO 3 obtained from acid and citrate precursor, respectively. The maximum surface areas (40 m 2 /g) are obtained for Co-W-N nitrides synthesized at 700 °C. We have investigated the change in pore volume and pore diameter when the synthesis conditions are changed. The thermogravimetric and differential thermal analysis studies corroborate the fine particle nature of the materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.