▎ 摘　　要

Graphene supported Co rich bimetallic connected Core-Shell nano-alloy structure, characterized by Pt core dispersed on interconnected Co-shell, was formulated for improved hydrogen generation and electro-oxidation. Several samples of Graphene based Co-Pt nano-hybrids were synthesized varying the weight ratios G:Co:Pt and characterized morphologically along with electrochemically using SEM EDAX, HRTEM, XRD and cyclic voltammetry respectively. These synthesized materials were tested as nano-catalysts for hydrogen generation from sodium borohydride and for electro-oxidation of borohydride solution. Based on morphology, four major models of nano-hybrids namely mixed segregated-core-shell (M-1), nano-hybrid-alloy (M-2), connected core(Pt)-shell(Co) (M-3) and core(Co)-shell(Pt) (M-4) were identified over the whole composition range. Among these, connected, core(Pt)-shell(Co) nano-alloy, corresponding to the composition 1:2:1 (G:Co:Pt), exhibits the best values for all the performance indices namely ECSA (112 m(2)gm(-1)), current density (0.55 A/cm(2)), mass specific activity (95-125 A gm(-1)) for electro-oxidation of Borohydride and activation energy (27.171 kJ mol(-1) for hydrogen generation. The catalyst-cost analysis for continuous production of hydrogen using G-Co-Pt catalyst, reveals that the use of Co rich connected core -shell catalyst reduces the cost by one order of magnitude compared to all other model catalysts. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.