Enhanced photocatalytic activity and mechanism insight of copper-modulated lead-free Cs(2)AgSbCl(6) double perovskite microcrystals

Lead halide perovskites are prospective candidates for CO(2) photoconversion. Herein, we report copper-doped lead-free Cs(2)AgSbCl(6) double perovskite microcrystals (MCs) for gas-solid phase photocatalytic CO(2) reduction. The 0.2Cu@Cs(2)AgSbCl(6) double perovskite MCs display unprecedented CO(2) photoreduction capability with CO and CH(4) yields of 412 and 128 μmol g(−1), respectively. The ultrafast transient absorption spectroscopy reveals the enhanced separation of photoexcited carriers in copper-doped Cs(2)AgSbCl(6) MCs. The active sites and reaction intermediates on the surface of the doped Cs(2)AgSbCl(6) are dynamically monitored and precisely unraveled based on the in-situ Fourier transform infrared spectroscopy investigation. In combination with density functional theory calculations, it is revealed that the copper-doped Cs(2)AgSbCl(6) MCs facilitate sturdy CO(2) adsorption and activation and strikingly enhance the photocatalytic performance. This work offers an in-depth interpretation of the photocatalytic mechanism of Cs(2)AgSbCl(6) doped with copper, which may provide guidance for future design of high-performance photocatalysts for solar fuel production.