The advent of Z-scheme heterojunction makes it possible to improve the CO 2 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/InVO 4 :La) based on La single atom anchored on black phosphorus for photocatalytic CO 2 reduction with ≈100% CO selectivity is successfully constructed. The CO generation rate of BP:La/5-InVO 4 :La is ≈7.9 and 4.9 times higher than black phosphorus and InVO 4 , respectively. The results of X-ray photoelectron spectroscopy, photoluminescence, and density functional theory indicate that the BP:La/InVO 4 :La belongs to the Z-scheme heterojunction, and the La single atom plays multiple roles such as regulating surface active sites, promoting CO 2 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 selectivitydetermining steps. The results are expected to provide unique ideas for the rational design of rare earth composite photocatalyst.

It is still a great challenge to obtain multicolor tunable luminescence and improve the stability of luminescence through reasonable design of materials in the field of white light-emitting diodes (WLEDs). In particular, it is more important to improve the luminescence intensity and stability of blue-emitting materials. Here, the properties of CsPbBr 3 , CsPbBr 3 :Na , and NaPbBr 3 are investigated theoretically by using density functional theory (DFT). Based on the DFT theoretical calculation results, it is assumed that unexpected performance may be achieved by replacing Cs in CsPbBr 3 with Na or passivating the surface of CsPbBr 3 with Na. As expected, the tunable luminescence from blue to green is successfully achieved from CsPbBr 3 :Na, and the stability is improved. After experimental optimization, the obtained CsPbBr 3 :Na (CPBN-4) with high luminescence stability is used as blueemitting materials to construct the WLED devices with excellent color quality (CRI 92) and correlated color temperature of 9582 K.