The influence of oxygen vacancies in ZnO/RuO2 crystal structure on the photoelectrocatalytic efficiency for hydrogen production

The development of catalysts for the electrochemical reaction of hydrogen evolution is essential for the improvement of the water electrolysis process and the clean energy transition. Although catalysts from the platinum group are the most effective, their shortage and high-cost limit widespread commercial application. In this study, we developed catalysts in which ruthenium was replaced by more affordable ruthenium dioxide, and its amount was reduced by using abundant zinc oxide. The ZnO/RuO2 composite was prepared by microwave processing of precipitate and further thermally modified at 300 and 600 C, in order to examine the influence of oxygen vacancies on (photo)electrocatalytic activity in the water electrolysis reaction. Thermal stability of catalysts was determined by thermo-gravimetric/differential thermal analysis (TG/DTA) technique, while the phase composition and crystal defects were determined by X-ray powder diffraction (XRD) and photoluminescence (PL) spectroscopy, respectively. Electroand photoelectrocatalytic activity of the composite toward hydrogen evolution reaction was tested by linear voltammetry in acidic and alkaline electrolyte.