Short communicationZnO2-promoted ZnO as an efficient photocatalyst for the photoreduction of carbon dioxide in the presence of water

•The hybrid ZnO2/ZnO was produced by an H2O2 treatment procedure with varying concentrations.•The total yield of 1.0Zn-60 increased from 3.5 μmol L− 1 to 73.5 μmol L− 1 of pristine ZnO.•The ZnO2/ZnO possesses abundant oxygen vacancies and OH, which are active sites of CH4 and CH3OH.

ZnO2-promoted ZnO photocatalysts were synthesized via H2O2 treatment, and their structural properties, optical properties, and activity for CO2 photoreduction were systematically studied. It was revealed that an excess of ZnO2 increased the surface area and enhanced oxygen vacancies, which significantly increased the adsorption capacity of molecular CO2. As a result, ZnO2-promoted ZnO showed a 21 times enhancement of CO2 photoreduction, with the total yield of 1.0Zn-60 increased from 3.5 μmol L− 1 to 73.5 μmol L− 1 of pristine ZnO. Based on the results of in situ CO2-IR and product distribution, a reaction mechanism for CO2 photoreduction on ZnO catalyst was proposed.

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