Design and fabrication of Zr-based MOF photocatalyst with functionalized moieties for CO2 reduction and coupling selective oxidation of benzyl alcohol

Zirconium-based metal organic frameworks (Zr-MOFs) are considered as promising photocatalysts due to their excellent stability, unique pore structure, and versatile photocatalytic applications. To strengthen the visible-light absorption, a well-designed targeted MOFs photocatalyst was fabricated by a solvothermal method with Co-tetrakis (4-carboxyphenyl) porphyrinate (Co-TCPP), 1,3,6,8-tetra(4-carboxyphenyl) pyrene (TBAPy), and Zr clusters as sensitizer, ligands and active sites, respectively. Benefiting from the excellent photo-responsiveness of Co-TCPP, the robust catalytic ability of Zr clusters, the promising electron transfer ability of pyrene moiety, the prepared Zr-Co MOF@TBAPy exhibit excellent photocatalytic performance and stability. A high reduction rate of 127.42 μmol g-1 h-1 from CO2 to CO, this is 3.5 and 2.8 times that of Zr-TBAPy and Zr-Co MOF, respectively. The photocatalytic performance of CO2 reduction coupling with selective oxidation of benzyl alcohol (BA) to benzaldehyde (BD) was also tested. The transferring pathway of photogenerated electron from the photosensitive unit to the active site mediated by the electron transport unit was further confirmed by density-functional theory (DFT) calculations, providing intuitive insights into the catalytic mechanism. This work manifests that well-designed MOFs integrated with functional moieties is a feasible strategy for developing high performance MOF based photocatalyst.