Promotion of electrocatalytic CO2 reduction on Cu2O film by ZnO nanoparticles

Cu2O films were prepared using an improved solution immersion method, whereas ZnO/Cu2O films were prepared using an electrodeposition method. Then, the pure Cu2O film electrodes and ZnO/Cu2O film electrodes were used to reduce CO2 to CH3OH. The crystal structure, morphology, particle size, and specific surface area of pure Cu2O films prepared under different immersion times and ZnO/Cu2O films prepared under different deposition times and Zn2+ concentrations were analyzed using X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller analysis. The electrolytic activity of the pure Cu2O film electrodes and ZnO/Cu2O film electrodes were studied. Under the same reaction conditions, the ZnO/Cu2O film electrode with the Zn2+ concentration of 0.05 M and the deposition time of 30 min had the highest total CH3OH yield of 315.656 μmol/cm2 and the fastest formation rate of 52.609 μmol/(cm2 h), and its faradaic efficiency was 45%, which was remarkably higher than that of pure Cu2O film electrodes under the same reaction conditions. This study highlighted that ZnO nanoparticles had a very good promotion of electrolytic CO2 reduction on Cu2O film.