Oxygen vacancies confined in hierarchically porous CsPbBr3@Pb-MOF through in situ structural transformation for promoting photocatalytic CO2 reduction

All-inorganic perovskite (CsPbBr3) nanocrystals (NCs) are exceptional candidates for photocatalysis due to their optimal band structure, high molar extinction coefficient, and long charge-carrier diffusion lengths. However, their inevitable instability and low charge transfer efficiency have prevented their widespread applications. A strategy that can improve both stability and charge separation efficiency is desperately required. Herein, by introducing an in situ structural transformation strategy, hydrophobic hierarchically porous CsPbBr3@Pb-MOF is obtained which exhibits high durability in water for more than 7 weeks and appealing thermal stability and resistance to anion intrusion. Meanwhile, abundant oxygen vacancies are detected which efficiently suppress the photogenerated charge recombination. As a result, impressive CO2 photoreduction activity is achieved with CsPbBr3@Pb-MOF as a catalyst. Through a gas–solid reaction (without sacrificial agents and photosensitizers), this CsPbBr3@Pb-MOF-2 composite exhibits a CO yield of 107 μmol g−1 h−1 with 99.2% selectivity under visible-light (λ > 420 nm) irradiation, surpassing most reported CsPbX3-based photocatalysts under similar conditions.