Z-scheme Heterojunction Photocatalyst Based on Lanthanum Single-Atom Anchored on Black Phosphorus for Regulating Surface Active Sites, therefore Enhancing Photocatalytic CO2 Reduction with ≈100% CO Selectivity

The advent of Z-scheme heterojunction makes it possible to improve the CO2 photoreduction efficiency of photocatalyst significantly. However, the reasonable construction of heterojunction and study of the photocatalytic mechanism remains a major challenge. Here, the Z-scheme heterojunction photocatalyst (BP:La/InVO4:La) based on La single atom anchored on black phosphorus for photocatalytic CO2 reduction with approximate to 100% CO selectivity is successfully constructed. The CO generation rate of BP:La/5-InVO4:La is approximate to 7.9 and 4.9 times higher than black phosphorus and InVO4, respectively. The results of X-ray photoelectron spectroscopy, photoluminescence, and density functional theory indicate that the BP:La/InVO4:La belongs to the Z-scheme heterojunction, and the La single atom plays multiple roles such as regulating surface active sites, promoting CO2 absorption, and increasing O defects, which can further contribute to the improvement of photocatalytic performance. The enhanced selectivity of the Z-scheme heterojunction is further demonstrated by calculating the rate-determining steps and selectivity-determining steps. The results are expected to provide unique ideas for the rational design of rare earth composite photocatalyst.

Automated summary

The advent of Z-scheme heterojunction has significantly improved the CO2 photoreduction efficiency of photocatalysts, but the construction of heterojunction and study of photocatalytic mechanism remain challenging. In this study, a Z-scheme heterojunction photocatalyst (BP:La/InVO4:La) based on a single atom of La anchored on black phosphorus was successfully constructed, achieving approximately 100% CO selectivity for CO2 reduction. The CO generation rate of BP:La/5-InVO4:La was approximately 7.9 and 4.9 times higher than that of black phosphorus and InVO4, respectively. X-ray photoelectron spectroscopy, photoluminescence, and density functional theory analysis confirmed that BP:La/InVO4:La is a Z-scheme heterojunction, with the La single atom playing multiple roles in regulating surface active sites, promoting CO2 absorption, and increasing O defects to improve photocatalytic performance. The enhanced selectivity of the Z-scheme heterojunction was further demonstrated by calculating the rate-determining steps and selectivity-determining steps. This study provides unique insights for the rational design of rare earth composite photocatalysts.