In-situ fabrication of Cu doped dual-phase CsPbBr3–Cs4PbBr6 inorganic perovskite nanocomposites for efficient and selective photocatalytic CO2 reduction

Converting CO2 into chemical fuels with renewable energy is an appealing approach for the deployment of carbon utilization technologies. Halide perovskite nanocrystals have been considered as one of the most promising light-harvesting materials in photocatalytic applications. However, most of the perovskite-based photocatalysts facilitate a two-electron reduction process to convert into CO, hard for the eight-electron CH4 production pathways. Herein, we develop a facile in-situ transformation strategy to fabricate Cu doped dual-phase CsPbBr3–Cs4PbBr6 inorganic perovskite nanocomposites (Cu/CsPbBr3-Cs4PbBr6 NCs). Compared to the pristine CsPbBr3 nanoparticles, the Cu/CsPbBr3-Cs4PbBr6 NCs have presented 4.2-fold higher photocatalytic efficiency for CO2 reduction and 303% increased electron consumption rate, in addition, the significant enhanced selectivity for converting CO2 into CH4 up to 78.6% has also been achieved. The in-situ transformation strategy opens an avenue for rational design perovskite-based photocatalysts for efficient and stable CO2 reduction.