Enhanced photocatalytic activity and mechanism insight of copper-modulated lead-free CsAgSbCl double perovskite microcrystals.

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