Regulating the Active Sites of Cs 2 AgBiCl 6 by Doping for Efficient Coupling of Photocatalytic CO 2 Reduction and Benzyl Alcohol Oxidation.

Halide perovskites exhibit outstanding optoelectronic properties, which make them an ideal choice for photocatalytic CO 2 reduction and benzyl alcohol (BA) oxidation. Nevertheless, the simultaneous realization of the above redox coupling reactions on halide perovskites remains a great challenge, as it requires distinct catalytic sites for different target reactions. Herein, the catalytic sites of Cs 2 AgBiCl 6 (CABC) are regulated by doping Fe for efficient coupling of photocatalytic CO 2 reduction and BA oxidation. The Fe-doped CABC (Fe: CABC) exhibits an enhanced visible-light response and effective charge separation. Experimental results and theoretical calculations reveal a synergistic interplay between Bi and Fe sites, where the Bi and Fe sites have lower activation energies toward CO 2 reduction and BA oxidation. Further investigations demonstrate that electrons and holes prefer to accumulate at the Bi site and Fe site under light irradiation, respectively, which creates favorable conditions for facilitating CO 2 reduction and BA oxidation. The resultant Fe: CABC achieves a high photocatalytic performance toward CO (18.5 µmol g -1  h -1 ) and BD (1.1 mmol g -1  h -1 ) generation, which surpasses most of the state-of-the-art halide photocatalysts. This work demonstrates a facile strategy for regulating the catalytic site for redox coupling reactions, which will pave a new way for designing halide perovskites for photocatalysis.