Engineering Synergistic Sites in a Cerium-Based Metal–Organic Framework for Photocatalytic CO2 Reduction

Abstract Photoreduction of CO2 to produce solar fuels is an important target. Redox-active Ce-based metal–organic frameworks (MOFs) are promising catalysts. Herein, we have synthesized an amino-functionalized Ce-based MOF, PKU-167 (PKU = Peking University). Upon introduction of Co(bpy)2Cl2 (bpy = 2,2′-bipyridine) to the skeleton of PKU-167, PKU-167-0.9Co achieved a high CO production rate of 18.4 mmol g–1 h–1 with a selectivity of 91.8% under visible-light irradiation and an apparent quantum yield of 1.97% at 425 nm. In situ characterizations and modeling reveal a synergistic adsorption–reduction mechanism, where amino groups enrich adsorption of CO2 for subsequent photoreduction on {Ce6} clusters and Co2+ sites in concert to achieve the optimal photocatalytic performance. This study will advance the rational design of redox-active Ce-based MOFs as efficient photocatalysts.