Catalytic Surface Specificity of Ni(OH)2 -Decorated Pt Nanocubes for the Hydrogen Evolution Reaction in an Alkaline Electrolyte.

Because the hydrogen evolution reaction (HER) in alkaline electrolyzers is initiated by water dissociation, the hydrogen evolution kinetics are sluggish even on highly active Pt catalysts. Here, we have synthesized Ni(OH)2 -decorated Pt nanocubes as a bifunctional catalyst to enhance the HER kinetics in an alkaline medium. Electrochemical cyclic voltammetry and CO-stripping measurements confirmed the selective deposition of Ni(OH)2 on the Pt(1 0 0) facets of nanocubes. Electrocatalytic HER activity of the Ni(OH)2 -decorated Pt nanocubes demonstrated that the bifunctional catalytic surface promotes the Volmer step kinetics and thus the Volmer/Tafel coupling dominant. As the result, catalytic surface specificity of Ni(OH)2 -decorated Pt nanocubes enhanced water dissociation, reduced contamination of OHad on Pt surface, and maintained long-term HER performance in alkaline electrolytes.