Highly selective photoreduction of CO₂ catalyzed by the encapsulated heterometallic-substituted polyoxometalate into a photo-responsive metal-organic framework

The highly selective photoreduction of CO₂ into valuable chemical fuels such as CO has been considered as an effective strategy to address modern energy and environmental issues. In this work, we have adopted the well-established impregnation approach to construct a P₂W₁₅Ni₃{Re(CO)₃}₃ @NU-1000 composite by incorporating heterometallic-substituted P₂W₁₅Ni₃{Re(CO)₃}₃ polyoxometalate (POM) into the pores of metal-organic framework (NU-1000) host. Upon light irradiation, the resulting P₂W₁₅Ni₃{Re(CO)₃}₃@NU-1000 composite can effectively photocatalyze CO₂ reduction, obtaining a CO production of 28982 μmol g⁻¹ with 93.5% selectivity during 10-h photocatalysis. The catalytic system exhibits great long-term recyclability and stability for at least four successive recycles. The proposed photocatalytic mechanism was confirmed by a series of photochemical and spectroscopic analyses.