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.

The development of green, efficient, and reusable photocatalysts is important for pollution degradation. In recent years, Cs₃Bi₂I₉ has been shown to be an effective photocatalyst. However, the rapid recombination of electrons and holes weakens the photocatalytic activity. In this work, the photogenerated electron transfer rate was promoted by ZIF-8 compositing with Cs₃Bi₂I₉, which effectively improved the pollutant degradation. After 50 min of visible light irradiation, Cs₃Bi₂I₉/ZIF-8 removed up to 98.2% of methylene blue (MB), which was 4.15 times higher than that of Cs₃Bi₂I₉ alone. In addition, the Cs₃Bi₂I₉/ZIF-8 composite still exhibited high photocatalytic activity after three cycling experiments. Our research offers a simple and efficient method for enhancing the photocatalytic activity of lead-free halide perovskites.