Hydrogen Evolution Reaction in Alkaline Media: Alpha- or Beta-Nickel Hydroxide on the Surface of Platinum?

Reducing the energy consumption of a hydrogen evolution reaction (HER) at a platinum (Pt) electrode is important for the hydrogen economy. Herein, we report the loading of alpha- or beta-nickel hydroxide (alpha- or beta-Ni(OH)(2)) nanostructures on the surface of a Pt electrode to improve its catalytic activity and stability for HER in alkaline electrolytes. Both experimental and theoretical studies reveal that beta-Ni(OH)(2) is a better co-catalyst of Pt than alpha-Ni(OH)(2) for promoting the HER, attributed to the higher water dissociation ability of beta-Ni(OH)(2), as well as the stronger interactions between beta-Ni(OH)(2) and the Pt electrode. Particularly, the over potential of the HER in 0.1 M KOH at 10 mA cm(-2) is decreased from 278 mV at the Pt electrode to 92 mV at the beta-Ni(OH)(2)/Pt electrode, and the Tafel slope decreased from 62 to 42 mV dec(-1), correspondingly. The performance of the beta-Ni(OH)(2)/Pt catalytic electrode surpasses that of most of the previously reported electrodes for the same purpose.