Semiconductive Amine-Functionalized Co(II)-MOF for Visible-Light-Driven Hydrogen Evolution and CO2 Reduction

A Co-MOF, [Co 3 (HL) 2 ·4DMF·4H 2 O] was simply synthesized through a one-pot solvothermal method. With the semiconductor nature, its band gap was determined to be 2.95 eV by the Kubelka–Munk method. It is the first trinuclear Co-MOF employed for photocatalytic hydrogen evolution and CO 2 reduction with cobalt–oxygen clusters as catalytic nodes. Hydrogen evolution experiments indicated the activity was related to the photosensitizer, TEOA, solvents, and size of catalyst. After optimization, the best activity of H 2 production was 1102 μmol/(g h) when catalyst was ground and then soaked in photosensitizer solution before photoreaction. To display the integrated design of Co-MOF, we used no additional photosensitizer and cocatalyst in the CO 2 reduction system. When −NH 2 was used for light absorption and a Co–O cluster was used as catalyst, Co-MOF exhibited an activity of 456.0 μmol/(g h). The photocatalytic mechanisms for hydrogen evolution and CO 2 reduction were also proposed.