Modification of Cs₂AgBiCl₆ Double-Perovskite Photocatalytic Activity by Br Doping

Developing highly efficient photocatalysts is crucial for photocatalysis technology. Many reports have demonstrated that element doping was an effective strategy for developing highly efficient photocatalysts by broadening the visible light absorption range and suppressing the recombination of photogenerated carriers. Herein, we doped the Br element into Cs₂AgBiCl₆ perovskite to widen the visible light absorption and enhance the charge transfer ability and then developed a highly efficient visible-light photocatalyst based on Cs₂AgBiCl₆. The results showed that Br doping could not only broaden the visible light absorption range of samples but also modulate the charge transfer ability of samples significantly. Among all the as-prepared samples, Cs₂AgBiCl₄Br₂ has the highest photocatalytic activity due to the best charge transfer ability, long lifetime of carriers, and broadened visible light absorption range, which can degrade 99.9% of methyl red in 28 min. Moreover, the cyclic experiments demonstrate that Cs₂AgBiCl₄Br₂ has good cycle stability. This study could provide a promising strategy for designing and developing new, highly efficient halide perovskite photocatalysts.