Boosting CO₂ photoreduction over perovskite quantum dots decorated with dispersed ruthenium nanoparticles

High efficiency CO₂ conversion materials are ideal for solar to carbon fuel conversion. Halide perovskite quantum dots (QDs) are highly desirable as catalysts and have been extensively investigated in the field of CO₂ photoreduction. The major challenge lies in the severe charge recombination and the weak ability to activate CO₂. Herein, we have identified dispersed Ru nanoparticles anchored on CsPbBr₃ (CPB) QDs as prospective photocatalysts for CO₂ reduction at ambient pressure with light irradiation. The optimized 0.45 % CPB@Ru reduced CO₂ to CO at a rate of 28.12 μmol g^-1 h^-1 without any sacrificial agent and co-catalysts, about 4 times higher than that of the CPB QDs (7.03 μmol g^-1 h^-1). Experiments and DFT calculations reveal that the as-prepared CPB@Ru showed increased photogenerated charge separation, CO₂ adsorption/activation and lower energy barriers for the formation of *COOH intermediate, which are crucial for enhancing the photocatalytic CO₂ reduction activity. This work provides a convenient pathway for designing high-performance perovskite photocatalysts with high selectivity and high catalytic activity using metal nanoparticle loading technology.