Enhanced photocatalytic activity and stability of 2D Cs3Bi2Br9 perovskite nanosheets synthesized via modified antisolvent method

Cs₃Bi₂Br₉ perovskite has attracted tremendous research attention in the field of photocatalysis due to its promising light-harvesting properties. However, its practical applications are hindered by water-induced degradation, limiting stability and photocatalytic activity. In this study, we address this challenge by synthesizing stable 2D Cs₃Bi₂Br₉ nanosheets through a modified anti-solvent reprecipitation method. Optimizing the isopropanol amount enabled unprecedented synthesis of 2D Cs₃Bi₂Br₉ nanosheets. SEM and HRTEM images show 2D stacked nanosheets of the sample prepared using 250 mL of isopropanol, while bulks and agglomerations were noticed in the samples prepared using different amounts of isopropanol. The Cs₃Bi₂Br₉ nanosheets exhibits the lowest charge recombination rate, hence achieving the highest degradation ratio of methylene blue, removing ∼80 % of the dye within 90 min under visible light attributed to their stability, facilitating efficient charge separation. Our study sheds light on the pivotal role of 2D morphology in enhancing the stability and photocatalytic performance of Cs₃Bi₂Br₉.