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)2 decorated Ni/C catalysts (Ni(OH)2-Ni/C) were prepared by a three-step electrochemical treatment of Ni/C. The existence of Ni(OH)2 was demonstrated by X-ray photoelectron spectroscopy (XPS), and the surface molar ratio of Ni(OH)2/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)2/Ni. On top of the “volcano”, the surface molar ratio of Ni(OH)2/Ni is 1.1:1, 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)2, which may help understanding the HOR mechanism on Ni.