Lead-Free Cs₂AgBiBr₆/TiO₂ S-Scheme Heterojunction for Efficient Photocatalytic Antibiotic Rifampicin Degradation

Abstract

Exploring efficient and stable halide perovskite-based photocatalysts is a great challenge due to the balance between the photocatalytic performance, toxicity, and intrinsic chemical instability of the materials. Here, the environmentally friendly lead-free perovskite Cs 2 AgBiBr 6 confined in the mesoporous TiO 2 crystal matrix has been designed to enhance the charge carrier extraction and utilization for efficient photocatalytic rifampicin degradation. The as-prepared Cs 2 AgBiBr 6 /TiO 2 catalyst was stable in air for over 500 days. An S-scheme heterojunction was formed between the (004) plane of Cs 2 AgBiBr 6 and the (101) plane of TiO 2 through the Bi–O–Br bonds. The built-in electric field at the interface efficiently promoted the photoinduced charge separation and carrier extraction. The Cs 2 AgBiBr 6 /TiO 2 -200 showed a 92.83% degradation efficiency of rifampicin within 80 min under simulated sunlight illumination (AM 1.5G 100 mW cm –2 ). This work offers an effective way for the construction of halide perovskite-based photocatalysts with high photocatalytic performance, good stability, and low toxicity simultaneously.