Enhanced Photocatalytic Performance of UiO-66-NH₂ MOFs by Ar Plasma Modification for Reduction of Cr (VI)

Defect engineering has a great effect on the properties of metal-organic frameworks (MOFs). In this study, the defective UiO-66-NH2 MOFs are successfully prepared by a rapid Ar plasma modification method. At certain experimental conditions (15 W radio frequency input power, 20 Pa working pressure, and 120 s Ar plasma modification time), the afforded UiO-66-NH2 shows significant enhancement in photocatalytic reduction of Cr(VI), and a maximum reduction efficiency of 68.5% is obtained. Advanced characterizations show that the plasma treatment generates missing-linker defects within the UiO-66-NH2 structure, which can enhance the separation of photogenerated electrons and holes and improve the photoreduction capability. The findings not only contribute to a better understanding of the relationship between the structure and performance of MOFs but also provide a simple approach for defect engineering of MOFs.