MOF-Derived Oxygen-Vacancy-Rich ZrO2/UiO-66-NH2 for Efficient Visible-Light-Driven Oxidation of Benzyl Alcohol

The development of efficient photocatalysts for selective organic transformations under visible light remains a major challenge in sustainable chemistry. In this study, we present a straightforward solvothermal strategy for fabricating a defect-engineered ZrO 2 /UiO-66-NH 2 hybrid material with abundant oxygen vacancies, enabling the visible-light-driven oxidation of benzyl alcohol to benzaldehyde. By optimizing the solvothermal treatment duration, the composite (UiO-66-NH 2 -2 h) achieves a 74.1% conversion of benzyl alcohol with > 99% selectivity toward benzaldehyde under mild conditions, substantially outperforming pristine UiO-66-NH 2 . Structural and mechanistic studies reveal that the solvothermal process induces the in situ formation of ultrasmall, uniformly dispersed ZrO 2 nanoparticles (~ 2.3 nm) within the MOF matrix, while simultaneously generating abundant oxygen vacancies, as confirmed by XPS, EPR, and HRTEM analyses. The defect-mediated electronic structure of the ZrO 2 /UiO-66-NH 2 hybrid enhances visible-light absorption, facilitates charge carrier separation, and promotes efficient activation of O 2 into superoxide radicals (·O 2 − ), the primary reactive species. Transient photocurrent measurements and electrochemical impedance spectroscopy further verify the improved charge separation efficiency. The synergistic interplay between oxygen vacancies and the intimate ZrO 2 /UiO-66-NH 2 interface provides a unique defect-mediated charge transfer pathway, distinguishing this system from conventional heterojunctions. This study demonstrates a facile, one-step approach to integrate defect engineering with interfacial hybridization in MOF-based photocatalysts, offering a scalable route for solar-driven organic synthesis. Graphical