Inorganic Copper-Based Halide Perovskite for Efficient Photocatalytic CO 2 Reduction.

In view of the toxicity of the Pb element, exploring eco-friendly Pb-free halide perovskites with excellent photoelectric properties is of great research and practical application significance. Herein, copper-based halide perovskite CsCuCl 3 and the corresponding Br - -substituted sample (CsCuCl 2 Br) are designed and explored as the catalysts for photocatalytic CO 2 reduction for the first time. A facile antisolvent recrystallization process with pre-prepared single crystals as the precursor is employed to controllably synthesize CsCuCl 3 and CsCuCl 2 Br microcrystals (MCs). The electronic structure and charge transfer property analysis by theoretical and experimental investigation reveal that CsCuCl 3 possesses a satisfying bandgap (1.92 eV) and conduction band minimum (CBM) to harvest the sunlight and drive the conversion of CO 2 to CH 4 and CO. The Br - substitution can not only narrow the bandgap but also facilitate the transportation of charge carriers. Thus, a total electron consumption rate of 44.71 μmol g -1 h -1 is achieved for CsCuCl 2 Br MCs, which is much better than that of same-sized CsPbBr 3 microcrystals or even better than many perovskite nanocrystal photocatalysts. This study suggests that Cu-based perovskites can serve as promising candidates for artificial photosynthesis or other photocatalytic applications, which may propose a new thought to construct lead-free, low-cost photocatalysts.