Insights into the sacrificial structure–activity relationship of a Ti-based metal–organic framework in an oxidative desulfurization reaction

Abstract

Insights into the relationship between the crystal structure and activity of metal–organic frameworks (MOFs) are meaningful to investigate the potential properties of pristine MOFs for targeted catalytic reactions. Herein, we develop a high-efficiency method for boosting the oxidative desulfurization (ODS) activity of Ti-MOF in the presence of H⁺. The ODS activity of pristine Ti-MOF prepared via a solvothermal approach is very poor at a low reaction temperature but can be enhanced in the presence of H⁺. Ti-MOF in the presence of H⁺ shows ultrahigh ODS activity that can eliminate 1000 ppm sulfur after 7 min at 30 °C with no catalytic activity loss after recycling 11 times. The turnover frequency value reaches 12.4 h⁻¹ at 30 °C, surpassing all the previously reported Ti-MOFs as ODS catalysts even at high temperatures. Characterization and quenching experimental results indicate that more uncoordinated Ti sites can be formed from slight damage to the structure of Ti-MOF during the catalytic reaction, and such exposed Ti sites can easily react with H⁺ and H₂O₂ to form Ti–hydroperoxo active species that determine the upgradation of ODS activity. This work provides a significant way to upgrade the catalytic activity of pristine Ti-MOFs for future application.