Space-confined growth of lead-free halide perovskite Cs3Bi2Br9 in MCM-41 molecular sieve as an efficient photocatalyst for CO2 reduction at the gas−solid condition under visible light

A facile and effective impregnation method is employed to synthesize the space-confined growth of lead-free halide perovskite Cs 3 Bi 2 Br 9 in MCM-41 molecular sieve. This MCM-41 @CBB (Cs 3 Bi 2 Br 9 ) composite shows an outstanding performance for the photocatalytic reduction of CO 2 to CO at the gas−solid condition under visible-light irradiation. The CO production rate of the MCM-41 @ 50 wt% CBB is determined to be 17.24 μmol g −1 h −1 , which greatly exceeds that of pure CBB (1.89 μmol g −1 h −1 ). The composite is highly stable showing no apparent decrease in the catalytic activity after 8 cycles of repeated experiment. The performance of space-confined growth of CBB nanoparticles in the serial molecular sieve exhibits 2.97–13.4 fold higher than that of pure CBB, respectively, which is superb than CPB (CsPbBr 3 ) and MCM-41 @CPB prepared in the same condition. The results are comparable with those reported for many lead halide perovskites, and are in the top among the lead-free perovskites, especially bismuth halide perovskites.