Z-Scheme Cu₂O/Cu/Cu₃V₂O₇(OH)₂·2H₂O Heterostructures for Efficient Visible-Light Photocatalytic CO₂ Reduction

Developing Z-scheme heterojunction photocatalysts has been regarded as a feasible approach to enhance the charge carrier lifetimes without reducing their redox potentials. In this work, a Z-scheme Cu3V2O7(OH)2·2H2O/Cu/Cu2O (denoted as CVO/Cu/Cu2O) heterojunction was successfully fabricated for the first time and used as photocatalysts for CO2 reduction. It was demonstrated that successively loading metallic Cu and Cu2O nanoparticles (NPs) on the surface of CVO could significantly improve the photocatalytic performance of CVO, and the highest CO evolution rate of 6.97 μmol·g–1·h–1 was obtained over the optimized CVO/Cu/Cu2O, which was 25.6 and 2.3 times higher than those of CVO and CVO/Cu2O, respectively. Moreover, CVO/Cu/Cu2O maintained a high stability even after five cycle reactions as compared to the binary CVO/Cu2O. The improved photocatalytic performance of CVO/Cu/Cu2O was mainly attributed to the enhanced visible-light absorption capability and the efficient Z-Scheme heterojunctions, which would boost the generation, migration, and separation of photogenerated charge carriers. This work may provide a strategy to design and fabricate copper vanadate-based Z-scheme heterojunction photocatalysts with high efficiency for CO2 reduction.