Design of Crystalline Reduction–Oxidation Cluster-Based Catalysts for Artificial Photosynthesis

Metal cluster-based compounds have difficulty finishing the photocatalytic carbon dioxide reduction reaction (CO₂RR) and water oxidation reaction (WOR) simultaneously because of the big challenge in realizing the coexistence of independently and synergistically reductive and oxidative active sites in one compound. Herein, we elaborately designed and synthesized one kind of crystalline reduction–oxidation (RO) cluster-based catalysts connecting reductive {M₃L₈(H₂O)₂} (M = Zn, Co, and Ni for RO-1, 2, 3 respectively) cluster and oxidative {PMo₉V₇O₄₄} cluster through a single oxygen atom bridge to achieve artificial photosynthesis successfully. These clusters can all photocatalyze CO₂-to-CO and H₂O-to-O₂ reactions simultaneously, of which the CO yield of RO-1 is 13.8 μmol/g·h, and the selectivity is nearly 100%. Density functional theory calculations reveal that the concomitantly catalytically reductive and oxidative active sites (for CO₂RR and WOR, respectively) and the effective electron transfer between the sites in these RO photocatalysts are the key factors to complete the overall photosynthesis.