Metal Center-Tuned Photocatalytic Carbon Dioxide Reduction for Frameworks with the Tetraphenylethene-Imidazole Ligand.

As heterogeneous photocatalysts that can effectively transform CO to CO, two MOFs with different metal centers, namely, M(tipe)(HO)·solvent (M = Ni named as and M = Co referred to as ), were synthesized by reactions of 1,1,2,2-tetrakis(4-(imidazole-1-yl)phenyl)ethene (tipe) with the corresponding metal perchlorate. Both and have 3D structures, in which the metal centers have the same coordination environment with the NO donor set. Driven by visible light, the CO production catalyzed by is 6734.1 μmol g with 45.3% selectivity, and in contrast, has 4601.3 μmol g CO production with 97.6% selectivity in 5 h. Through photoelectrochemical characterization, DFT calculations, and in situ FT-IR measurements, the photocatalytic CO reduction process catalyzed by and was investigated. The results show that the metal center of the MOF is crucial for photocatalytic CO reduction. This work offers an innovative approach for controlling the performance of photocatalytic CO reduction through tuning the metal centers of architectures.