Ni(OH)2-Ni/C for hydrogen oxidation reaction in alkaline media

The development of the hydrogen electrode is vital for the application of alkaline polymer electrolyte fuel cells(APEFCs).In this study,a series of Ni(OH)decorated Ni/C catalysts(Ni(OH)-Ni/C) were prepared by a three-step electrochemical treatment of Ni/C.The existence of Ni(OH)was demonstrated by X-ray photoelectron spectroscopy(XPS),and the surface molar ratio of Ni(OH)/Ni of the samples was estimated via an electrochemical method.The HOR catalytic activity of the catalysts was evaluated by a rotation disk electrode(RDE) method,and a "volcano plot" was established between the HOR exchange current(j0) and the surface molar ratio of Ni(OH)/Ni.On top of the "volcano",the surface molar ratio of Ni(OH)/Ni is1.1:1,the j0 of which was 6.8 times of that of Ni/C.The stability of the samples toward HOR was evaluated to be good.Our study added a systematic experimental evidence to the HOR research,showing that the HOR catalytic activity of Ni can be deliberately controlled via decoration of Ni(OH),which may help understanding the HOR mechanism on Ni.