Enhancing the Photocatalytic Activity of Lead-Free Halide Perovskite Cs₃Bi₂I₉ by Compositing with Ti₃C₂ MXene

In recent years, halide perovskite materials have become widely used in solar cells, photovoltaics, and LEDs, as well as photocatalysis. Lead-free perovskite Cs₃Bi₂I₉ has been demonstrated as an effective photocatalyst; however, the fast recombination of the photogenerated carriers hinders further improvements of its photocatalytic activity. In this work, Ti₃C₂ was composited with Cs₃Bi₂I₉ to promote the transfer and separation of photogenerated carriers, and thus the pollutant degradation efficiency was effectively improved. The visible-light photocatalytic reduction of Cs₃Bi₂I₉/Ti₃C₂ on rhodamine B (RhB), methylene blue (MB), and malachite green (MG) was as high as 97.3%, 96%, and 98.8%, respectively, improvements of almost 31.2%, 37.8%, and 37.2% compared to that of sole Cs₃Bi₂I₉. Our study provides a simple way to enhance the photocatalytic activity of lead-free halide perovskites.