Boosting Catalytic\nPerformance of MOF-808(Zr) by Direct\nGeneration of Rich Defective Zr Nodes via a Solvent-Free Approach

Abstract

Creation\nof rich open metal sites (defect) on the nodes\nof metal–organic\nframeworks (MOFs) is an efficient approach to enhance their catalytic\nperformance in heterogeneous reactions; however, direct generation\nof such defects remains challenging. In this contribution, we developed\nan in situ green route for rapid fabrication of defective MOF-808(Zr)\nwith rich Zr-OH/OH₂ sites (occupying 25% Zr coordination\nsites) and hierarchical porosity without the assistance of formic\nacid and solvent. The optimal MOF-808(Zr) not only displayed superior\nactivity in oxidative desulfurization (ODS) for removing 1000 ppm\nsulfur at ambient temperature within 20 min but also could convert\n3.8 mmol of benzaldehyde to (dimethoxymethyl)benzene within 90 s at\n30 °C. The turnover frequencies reached 45.4 h^–1 for ODS and 3451 h^–1 for acetalization, outperforming\nthe most reported MOF-based catalysts. Theoretical calculation and\nexperimental results show that the formed Zr-OH/OH₂ can\nreact with H₂O₂ to generate peroxo-zirconium\nspecies, which readily oxidize the sulfur compound. Our work provides\na new approach to the synthesis of defect-rich MOF-808(Zr) with the\naccessibility of active sites for target reactions.