The additive effect of graphene in nickel phosphate/graphene composite and enhanced activity for electrochemical oxidation of methanol

•The graphene can be as additive material to adjust the structure of nickel(ii) phosphate VSB-5.•There is strong guest-host interaction between the nickel phosphate (NiPO) and graphene.•The NiPO/G exhibits much higher electro-catalytic activity for methanol electro-oxidation.

Graphene doped nickel phosphate/graphene composite (NiPO/G) is prepared by the one-pot hydrothermal synthesis. NiPO/G shows a combined structure of nanospheres and flakes aggregate as well as graphene layered structure. There is strong guest-host interaction between the nickel phosphate (NiPO) and graphene. The change of the charge density of NiPO is revealed by Ni 2p XPS spectra where a down shift is observed on NiPO/G compared with the pure VSB-5. Impressively, the NiPO/G exhibits much higher electro-catalytic activity (12 times compared with VSB-5) and lower over-potential for methanol electro-oxidation than the pure VSB-5 in alkaline medium. The positive correlation between the scan rates and the anodic currents implys a single diffusion-controlled kinetic process. The enhancement of the electro-catalytic activity is due to the synergistic interaction effect between graphene and NiPO.

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