Electrocatalysis of hydrogen evolution on polycrystalline palladium by rhodium nanoislands in alkaline solution

Hydrogen evolution reaction (HER) was investigated on bimetallic Rh/Pd(poly) electrodes in alkaline solution. Bimetallic electrodes were obtained by a spontaneous deposition of rhodium on polycrystalline Pd. Characterization of obtained electrodes was performed ex situ by atomic force microscopy and by spectroscopic ellipsometry. The results have shown that the coverage of palladium substrate with the deposited Rh nanoislands was up to 50%, depending on the chosen deposition time. Electrochemical properties and catalytic activity of Rh/Pd(poly) nanostructures for HER were examined in 0.1 M NaOH solution by cyclic voltammetry and linear sweep voltammetry. Rh/Pd(poly) electrodes have shown an enhanced activity for HER with respect to bare Pd(poly), which was ascribed to the strong electronic interaction between palladium substrate and the deposited rhodium islands. The enhanced catalytic activity of 50% Rh/Pd(poly) for HER in alkaline solution is comparable to that of bare Pt(poly)