Influence of thermal treatment on the photoelectrocatalytic activity of 2ZnO/1RuO2 composites as photoanode for water splitting

In this study, ZnO as a semiconductor and RuO2 as a metal-like conductor were combined in a composite and tested as a photoanode for water splitting, i.e. green hydrogen and oxygen production. ZnO/RuO2 composite in the mass ratio of 2:1 was prepared using microwave processing of a precipitate. To investigate the influence of oxygen vacancies as defects in the crystal structure on (photo)electrocatalytic efficiency for hydrogen and oxygen production, the composite was annealed at 300 and 600?C. The phase composition, morphology, and optical properties of as-prepared and annealed composites were analyzed in detail. The (photo)electrocatalytic activity of composites for HER and OER was examined in NaOH and H2SO4 using linear sweep voltammetry. The (photo)electrocatalytic properties of the ZnO/RuO2 composites were correlated with their physicochemical characteristics with emphasize on oxygen vacancies.