Enhanced H2 evolution reaction due to H spillover during electrolytic reduction of water on a Au/TiO2 electrode

Abstract TiO2 has limited applicability as an alternative to noble metal electrocatalysts for the hydrogen evolution reaction in aqueous solution due to the possibility of hydrogen intercalation under cathodic potential. In this work, the electrolytic reduction of H2O on TiO2 electrodes in alkaline media is investigated. Cyclic voltammetry experiments, combined with X-ray diffraction and in situ UV–vis results, indicate that most of the H species produced during the reaction diffuse into the TiO2 bulk at high cathodic potential. However, the presence of Au particles on the TiO2 electrodes greatly enhances H2O reduction and H2 production due to the H spillover effects, i.e., the H species produced on the TiO2 spill over to the Au nanoparticles and recombine to form H2. This result provides a new way of thinking about the design of more effective catalysts for the hydrogen evolution reaction using transition metal oxides.