Nickel metal-organic frameworks for visible-light CO 2 reduction under mild reaction conditions.

Photochemical CO 2 conversion into carbon fuel is a promising route to explore renewable energy and relieve climate change. However, it is still a key challenge to achieve high selectivity to CO and simultaneously achieve high conversion efficiency in photochemical CO 2 reduction. Herein, we demonstrate the effect of Ni metal centers as catalytic active sites for the photocatalytic conversion of CO 2 to CO by designing and constructing Ni metal-organic framework (Ni-MOF) materials. In pure CO 2 , Ni-MOF catalyst exhibits outstanding performance for visible-light-driven reductive CO 2 deoxygenation with a high CO evolution rate of 19.13 μmol h -1 (per 1 mg of catalyst) and CO selectivity of 91.4%, which exceeds those of most reported systems. Upon using isostructural Co-MOF as the catalyst to replace Ni-MOF, a moderate performance towards CO 2 photoreduction and low CO selectivity (40.1%) were observed, implying that the performance of CO 2 photoreduction and CO selectivity are dependent on unsaturated metal centers.