Construction of S‐Scheme Cs 2 AgBiBr 6 /BiVO 4 Heterojunctions with Fast Charge Transfer Kinetics Toward Promoted Photocatalytic Conversion of CO 2

Abstract Lead‐based halide perovskites (LHPs) have been widely explored by researchers in the field of photocatalysis. However, the poor stability and toxicity of LHPs limit their large‐scale applications. Here, lead‐free Cs 2 AgBiBr 6 /BiVO 4 (CABB/BVO)‐X% (X = 30, 50, 100) S‐scheme heterojunction composites are prepared by electrostatic assembly, and their catalytic activity for photoreduction of CO 2 is evaluated. After 3 h of simulated solar irradiation, the prepared CABB/BVO‐50% composites show the highest CO yield and electron consumption rate of 143.59 and 352.22 µmol g −1 , which are 9.2 and 7.8 times higher than that of CABB alone, respectively. In addition, the prepared CABB/BVO‐50% photocatalysts exhibit 81.5% high selectivity for CO. The generation of an internal electric field (IEF) between the two materials and the generation of S‐scheme heterojunctions are powerfully confirmed by employing various characterization techniques and DFT calculations. The low carrier recombination rate, bandgap‐matched heterointerfaces, and exceptional S‐scheme charge transfer mechanism are primarily responsible for the outstanding performance. This work provides new insights into the design of efficient lead‐free perovskites‐based photocatalytic materials.