Cerium salt-assisted defect engineering in solvent-free-synthesized UiO-66 (Zr) for enhanced oxidative desulfurization of model oils

The development of efficient oxidative desulfurization (ODS) catalysts is of critical practical significance for obtaining clean fuel energy. UiO-66(Zr), as a significant member of Zr-MOFs, has garnered extensive attention due to its advantages such as good porosity and excellent stability. The reasonable design of defective UiO-66(Zr) just compensates for the dearth of accessible active sites of the original MOFs. In this study, we adopt a solventfree green preparation strategy to obtain defective UiO-66(Zr), where a small amount of CeCl3.7H2O is added and the unique advantage of MOFs with abundant ligand defects plays a key role in improving ODS performance. The optimal sample can completely eliminate 1000 ppm DBT at 50 degrees C for 6 min, with a high turnover frequency (12.33 h- 1) and significant catalytic activity (35.33 mmol g- 1 h- 1), and the catalyst can maintain high activity for multiple cycles. The excellent properties may be attributed to the high melting point of CeCl3.7H2O, which leads to the presence of dangling COOH and exposed Lewis Zr sites. Experimental findings demonstrate that the exposed Zr site is capable of generating the active species .O2- with H2O2, which effectively eliminates thiophene sulfur compounds. In brief, this work enriches the understanding of solvent-free methods for the synthesis of defective UiO-66(Zr) and provides an effective strategy for ODS catalyst development.