Synthesis and Characterization of Nitrogen Doped Reduced Graphene Oxide (N-rGO) Supported PtCu Anode Catalysts for Direct Methanol Fuel Cell

Incomplete methanol oxidation and rapid activity degradation of electro-catalysts are key barriers to successful commercialization of direct methanol fuel cell (DMFC). To address these problems, we report the synthesis of platinum-copper (PtCu) alloy nanoparticles supported on nitrogen doped reduced graphene oxide (N-rGO) as the anode catalyst for the efficient electro-oxidation of methanol. Catalysts with varying molar ratios of PtCu were fabricated using impregnation reduction method and their electrochemical performance was compared with the commercially available Pt/C (20 wt%) anode catalyst. The electro-catalytic activity of the synthesized PtCu (1:2)/N-rGO catalyst was found to be much higher to those that observed for Pt/N-rGO and Pt/C catalyst as revealed by cyclic voltammetry, electrochemical impedance spectroscopy and electron transfer measurements. The enhanced electrochemical activity of PtCu (1:2)/N-rGO catalyst is not only attributed to strong interfacial interaction between the nitrogen group of N-rGO and PtCu active metal phase but also to the altered electronic structure of Pt as a result of Cu alloying. This reduces the adsorption of CO and OH- species on Pt surface, thereby creating more Pt active sites for methanol electro-oxidation; thus faster kinetics is exhibited. These results indicate the potential application of PtCu/N-rGO catalyst as an anode material in a DMFC.