Ce3+ self-doping CeO2-x@CuO nanowires arrays on copper mesh at the gas-liquid interface: Enhanced performance of reducing CO2 to methanol under visible light

S-scheme heterojunction can accelerate the separation of photogenerated electron-hole pairs and retain strong redox ability, so it has outstanding advantages and application prospects in the field of photocatalysis . The Ce 3+ self-doping CeO 2-x @CuO nanowires arrays on copper mesh were synthesized with the strategy of surface hydrogenation and hydrothermal calcination method. The morphology, composition and properties of the catalysts were determined by SEM, TEM, EDS , UV-VIS, PL , CO 2 -TPD and other characterization methods. Ce 3+ self-doping introduces O vacancies on the surface of CeO 2 without introducing heteroatoms. The O vacancies of CeO 2-x could enhance the adsorption, activation and reduction of CO 2 . The existence of coaxial S-scheme heterojunctions could effectively enhance the light absorption range and the separation of photo-generated charges. The photocatalytic activity of the composite catalyst was much higher than that of pure CuO/copper mesh (CM) and CeO 2 , and the difference in activity of catalysts composed of different proportions was studied. When the Ce 3+ self-doping CeO 2-x loading was moderate, the methanol yield reached 6.73 μmol·g cat −1 after 4 h reaction under visible light , which is 5.26 times of CuO/CM and 9.35 times of CeO 2 . The reduction mechanism of the composite catalyst at the gas-liquid interface was studied. This work demonstrates a feasible strategy to create efficient S-scheme heterojunction photocatalysts with rich active surface O vacancies for photocatalytic CO 2 reduction.