Lead-Free Cs3Bi2Br9 perovskite In-situ growth on 3D Flower-like g-C3N4 microspheres to improve photocatalytic performance

Nitrogen oxide (NOx) removal has long been a subject that has motivated researchers to develop a diverse range of techniques, including physical adsorption, biofiltration, low temperature plasma, selective catalytic reduction, and photocatalytic oxidation. In this work, Cs3Bi2Br9 lead-free perovskite was synthesized via in-situ growth on a 3D flower-like g-C3N4 microsphere, which uses a series of Cs3Bi2Br9/g-C3N4 (labeled as X% CBB/CN, where X = 5, 10, 20, 30, and 50) heterojunctions for the photocatalytic removal of NOx. The efficiency of NO removal was enhanced considerably, compared with that of the pristine elements, when irradiated with a 300 W Xe lamp with the concentration of NO at the ppb level. The results of photocurrent measurements and electrochemical impedance spectroscopy are consistent with the results of the NO removal test. Electron spin resonance results verified that ⋅OH and ⋅O2− are formed under visible light irradiation. We report the detailed mechanism for the photocatalytic process of NO removal by CBB/CN heterojunctions and provide insights into the potential applications of lead-free perovskite-based heterostructures in the field of photocatalysis.