Boosting CsPbBr3-Driven Superior and Long-Term Photocatalytic CO2 Reduction under Pure Water Medium: Synergy Effects of Multifunctional Melamine Foam and Graphitic Carbon Nitride (g-C3N4)

Achieving high-efficiency and long-term CO2 photoreduction under an aqueous environment is still a challenge for CsPbBr3-based catalysts due to the poor humidity resistance. Herein, multifunctional melamine foam (MF) and graphitic carbon nitride (g-C3N4) are selected to modify CsPbBr3, successfully realizing efficient and long-term CO2 reduction under pure H2O medium. The 3D framework of MF can support CsPbBr3, avoiding its degradation due to direct contact with the aqueous solution. In addition, the abundant porosity of MF can accelerate H2O evaporation, achieving sufficient blending of CO2 with H2O vapor. These functions lead to the enormously enhanced conversion efficiencies of MF/CsPbBr3 and MF/g-C3N4 compared to powdery catalysts. Photocatalytic activities of MF/CsPbBr3-g-C3N4 are further improved due to the accelerated charge migration, and accordant sites of electron accumulation and CO2 adsorption in composites. The best product yield of the composite is 975.57 mu mol g(-1) h(-1), and the corresponding electron consumption rate reaches 2571.27 mu mol g(-1) h(-1), surpassing almost all the already reported CsPbBr3-based catalysts whether in H2O or organic solvent media. Moreover, the strong surface hydrophobicity and excellent photothermal effect of MF/CsPbBr3-g-C3N4 result in long-term and stable photocatalytic activity, with no obvious CO and CH4 decrease after continuous reaction for 76 h.