Construction of dual ligand Ti-based MOFs with enhanced photocatalytic CO2 reduction performance

Abstract As a typical titanium based MOF, NH2-MIL-125(Ti) has been widely used as catalyst for photocatalytic CO2 reduction due to its abundant photoactive sites, large surface area and high porosity. However, the CO2 conversion efficiency of NH2-MIL-125(Ti) is still limited due to its weak electron transfer ability. Herein, Zn(II)-porphyrin is selected as photosensitizer to directly coordinate with titanium oxo clusters to endow NH2-MIL-125(Ti) with a second efficient photoexcitation path to enhance the photocurrent intensity and CO2 adsorption ability, which realizes 11-fold enhancement in the CO2/CO conversion efficiency. It is found that the optimized band structure of the dual ligand Ti-based MOFs (D-TiMOF) after the incorporation of Zn(II)-porphyrin contributes a lot for the enhanced photoelectric conversion ability and CO2 adsorption ability. This research sheds light on designing efficient CO2/CO conversion MOFs based photocatalyst via porphyrin-metal oxo clusters coordination.