Self-supported CsPbBr3/Ti3C2Tx MXene aerogels towards efficient photocatalytic CO2 reduction

Aerogels, especially MXene aerogels, are an ideal multifunctional platform for developing efficient photocatalysts for CO2 reduction because they are featured by abundant catalytic sites, high electrical conductivity, high gas absorption ability and self-supported structure. However, the pristine MXene aerogel has almost no ability to utilize light, which requires additional photosensitizers to assist it in achieving efficient light harvesting. Herein, we immobilized colloidal CsPbBr3 nanocrystals (NCs) onto the self-supported Ti3C2Tx (where Tx represents surface terminations such as fluorine, oxygen, and hydroxyl groups) MXene aerogels for photocatalytic CO2 reduction. The resultant CsPbBr3/Ti3C2Tx MXene aerogels exhibit a remarkable photocatalytic activity toward CO2 reduction with total electron consumption rate of 112.6 μmol g-1h-1, which is 6.6-fold higher than that of the pristine CsPbBr3 NC powders. The improvement of the photocatalytic performance is presumably attributed to the strong light absorption, effective charge separation and CO2 adsorption in the CsPbBr3/Ti3C2Tx MXene aerogels. This work presents an effective perovskite-based photocatalyst in aerogel form and opens a new avenue for their solar-to-fuel conversions.