Hydrogen Evolution Reaction on Platinum Catalyzed by Palladium and Rhodium Nanoislands

Pd/Pt(poly) and Rh/Pt(poly) bimetallic electrodes prepared by spontaneous deposition of Pd and Rh nanoislands on Pt(poly) at submonolayer coverage were explored as catalysts for hydrogen evolution reaction (HER) in alkaline media. Characterization of bimetallic surfaces was performed ex situ by height and phase AFM imaging and in situ by cyclic voltammetry. HER was investigated by linear sweep voltammetry in 0.1 M NaOH. Both Pd/Pt(poly) and Rh/Pt(poly) surfaces exhibited an enhanced catalysis for HER with respect to bare Pt(poly), which is explained by a strong synergistic electronic effect of platinum substrate on the deposited Pd or Rh nanoislands. This electronic effect leads to the lowering of a binding energy of adsorbed hydrogen intermediate and consequently to the lowering of the overpotential for HER