Top-down synthesis of high-performance lead-free double layer perovskite Cs4CuSb2Cl12 with large specific surface area and rich defects for efficient photocatalytic CO2 reduction

In recent years, there has been significant progress in the field of perovskite research. One area that has garnered attention is lead-free perovskite due to its stability, lack of toxicity, and exceptional optical properties. In this study, we successfully synthesized environmentally friendly, small-sized double-layer perovskites Cs4CuSb2Cl12 using a top-down method involving ball milling. The resulting Cs4CuSb2Cl12 nanoparticles exhibit high photocatalytic capacity, with a 1.60-fold increase in CO yield under full spectrum irradiation for 4 h, from 45.01 μmol/g to 72.17 μmol/g compared to the original material. Additionally, CO evolution under NIR light illumination for 4 h increased from 2.31 μmol/g (0- Cs4CuSb2Cl12) to 5.37 μmol/g (3- Cs4CuSb2Cl12). The top-down treatment resulted in smaller particle size and larger specific surface area, shortened carrier transmission distance, and enhanced electron concentration. Furthermore, the material’s surface presented a high concentration of defects, displayed high absorption capability across the entire spectrum, and abundant photocatalytic active sites. This study introduces an effective and environmentally-friendly strategy to enhance the photocatalytic efficiency of Cs4CuSb2Cl12, providing a new perspective for providing the photocatalytic capability of these materials.