Boosting Photocatalytic CO2 Reduction on CsPbBr3 Perovskite Nanocrystals by Immobilizing Metal Complexes

Converting CO2 into chemical fuels with a photocatalyst and sunlight is an appealing approach to address climate deterioration and energy crisis. Metal complexes are superb candidates for CO2 reduction due to their tunable catalytic sites with high activity. The coupling of metal complexes with organic photosensitizers is regarded as a common strategy for establishing photocatalytic systems for visible-light-driven CO2 reduction. While most of the organic photosensitizers generally contain precious metals and are available through onerous synthetic routes, their large-scale application in the photocatalysis is limited. Halide perovskite nanocrystals (NCs) have been considered as one of the most promising light-harvesting materials to replace the organic photosensitizers due to their tunable light absorption range, low cost, abundant surface sites, and high molar extinction coefficient. Herein, we demonstrate a facile strategy to immobilize Ni(terpy)22+ (Ni(tpy)) on inorganic ligand-capped CsPbBr3 NCs and to apply this hybrid as a catalyst for visible-light-driven CO2 reduction. In this hybrid photocatalytic system, the Ni(tpy) can provide specific catalytic sites and serve as electron sinks to suppress electron–hole recombination in the CsPbBr3 NCs. The CsPbBr3-Ni(tpy) catalytic system achieves a high yield (1724 μmol/g) in the reduction of CO2 to CO/CH4, which is approximately 26-fold higher than that achieved with the pristine CsPbBr3 NCs. This work has developed a method for enhancing the performance of photocatalytic CO2 reduction by immobilizing metal complexes on perovskite NCs. The methodology we present here provides a new platform for utilizing halide perovskite NCs for photocatalytic applications.