Room Temperature Photodriven Ru(II)-Tripyridine Supramolecular Photosensitizer Synergistically Catalyzes Carbon Dioxide Cycloaddition with Metal Nanoclusters

Photocatalytic CO₂ cycloaddition under mild conditions is of great significance for achieving renewable carbon resource recycling and environmental protection. To enhance the efficiency of this light-driven conversion process, this study constructed an efficient photocatalytic system composed of a photosensitizer and a metal nanocluster catalyst via a coordination bond strategy. X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy, and density functional theory confirmed the successful formation of coordination bonds. With the help of coordination bonds, the light absorption capacity and photoresponse characteristics of the metal nanoclusters were significantly enhanced. This enhancement was further verified by UV-vis diffuse reflectance spectroscopy, cyclic voltammetry, and in situ electron paramagnetic resonance spectroscopy. In the CO₂ cycloaddition reaction, the Mn₄Nb₂/S2 photocatalytic system with coordinated synergy exhibited excellent catalytic performance under mild conditions (25 °C, 1 atm CO₂, 12 h), achieving the maximum turnover number of 1652 and the cyclic propylene carbonate yield of 98.2%. Moreover, the catalyst cycle stability test demonstrated that the catalyst maintained high activity after 10 consecutive uses. This study provides new insights into highly efficient photocatalytic CO₂ cycloaddition under mild conditions.