Highly-efficient and stable photocatalytic activity of lead-free Cs₂AgInCl₆ double perovskite for organic pollutant degradation

Photocatalytic applications of halide perovskites have attracted increasing attention. However, lack of stability and lead toxicity of lead halide perovskites have hindered their applications. Metal halide double perovskite (DP) Cs₂AgInCl₆ is a stable, environment-friendly semiconductor with direct band gap, and then the best promising alternative to lead halide perovskites. Here, the applications of Cs₂AgInCl₆ DP to photocatalytic degradation of organic pollutants have been developed, in which the octahedral Cs₂AgInCl₆ DP particles (~3.33 eV) were prepared by precipitation from acid solutions. The as-prepared samples exhibit high photocatalytic activity, which can degrade about 98.5% of water-insoluble carcinogen Sudan Red III in only 16 min, and have a good stability for 5 cycle operations. Furthermore, the Cs₂AgInCl₆ DP also can degrade Rhodamine B, Methyl orange and Methyl red efficiently, demonstrating a highly-efficient and stable ethanol solvent-based photocatalytic system for organic pollutants degradation. The high photocatalytic activity could be attributed to direct band gap and long carrier lifetime of Cs₂AgInCl₆ DP. These unique features of Cs₂AgInCl₆ DP indicate that it could have a good application prospect for photocatalytic degradation of organic pollutants.