High-entropy zeolitic imidazolate framework for efficient oxidative desulfurization of diesel fuel: Towards complete sulfur removal and valuable sulfone production

Abstract

Diesel fuel contains a significant amount of aromatic sulfur compounds, which are pollutants and conventionally subjected to hydrodesulfurization to generate low-value hydrogen sulfide for removal. However, these aromatic sulfur compounds possess high economic value and exhibit crucial applications. In this study, we successfully synthesized a high-entropy zeolitic imidazolate framework (HE-ZIF) with a high specific surface area and exposed active sites via a mechanochemistry-assisted strategy. The utilization of HE-ZIF in an oxidative desulfurization system (ODS) with oxygen (O2) allows for the direct catalytic oxidation of sulfides, including dibenzothiophene (DBT) in diesel fuel. This process yields DBT to dibenzothiophene sulfone (DBTO2), a highly valuable product for achieving deep desulfurization. Additionally, the application of HE-ZIF achieves complete sulfur removal, reaching a 100% removal efficiency. Furthermore, it facilitates the recycling of high-value products, thereby enhancing the overall sustainability of the process. The investigation reveals that the synergistic effect between metals plays a crucial role in enhancing ODS performance. Furthermore, the microporous structure of HE-ZIF facilitates effective contact between the O2 oxidant and active sites. The presence of multiple metal active sites, abundant oxygen vacancies, and the microporous nature of the HE-ZIF material contribute to its ultra-high catalytic activity, thus opening new avenues for developing highly active catalysts for ODS and other catalytic reactions.