Recycling and Recovery of Deactivated CsPbBr₃ Perovskite after Photocatalytic CO₂ Reduction Reaction

CsPbBr 3 perovskite nanocrystals have emerged as promising candidates for photocatalysis. However, their conversion efficiency is hampered by material instability, and the accumulation of deactivated perovskites produced after photocatalytic reactions raises significant environmental concerns. To address this issue, we developed a mechanochemical grinding approach assisted by oleylamine as an additive to restore the optical properties and photocatalytic activity of deactivated CsPbBr 3, which was due to aggregation in the photocatalytic CO 2 reduction reaction. Upon regeneration, the CsPbBr 3 nanocrystals exhibited an average length of 34.21 nm and an average width of 20.86 nm, demonstrating optical properties comparable to those of the pristine CsPbBr 3 nanocrystals. Moreover, they achieved a conversion efficiency of 88.7% compared with pristine CsPbBr 3 nanocrystals in the photocatalytic CO 2 reduction reaction. This method effectively enhanced the utilization of CsPbBr 3, offering a novel approach for the recycling and recovery of perovskite materials and thereby minimizing material waste and environmental pollution.