Efficient Diesel Desulfurization by Novel Amphiphilic Polyoxometalate-Based Hybrid Catalyst at Room Temperature

Abstract

Amphiphilic hybrid catalysts were prepared by modifying [SMo12O40]2− with tetrabutylammonium bromide (TBAB), 1-butyl-3-methylimidazole bromide (BMIMBr) and octadecyl trimethyl ammonium bromide (ODAB), respectively. The prepared catalysts were characterized by IR, XRD, SEM, TG and XPS. The desulfurization performance of the catalysts was investigated in model oil and actual diesel using hydrogen peroxide (H2O2) as an oxidant and acetonitrile as an extractant. All catalysts exhibited favorable activity for removing sulfur compounds at room temperature. Dibenzothiophene (DBT) can be nearly completely removed using SMo12O402−-organic catalysts within a short reaction time. For different sulfur compounds, the [TBA]2SMo12O40 catalyst showed a better removal effect than the [BMIM]2SMo12O40 and [ODA]2SMo12O40 catalyst. The [TBA]2SMo12O40 dissolved in extraction solvent could be reused up to five times in an oxidative desulfurization (ODS) cycle with no significant loss of activity. The [BMIM]2SMo12O40 performed as a heterogeneous catalyst able to be recycled from the ODS system and maintained excellent catalytic activity. The catalysts showed a positive desulfurization effect in real diesel treatment. Finally, we described the ODS desulfurization mechanism of DBT using SMo12O402−-organic hybrid catalysts. The amphiphilic hybrid catalyst cation captures DBT, while SMo12O402− reacts with the oxidant H2O2 to produce peroxy-active species. DBT can be oxidized to its sulfone by the action of peroxy-active species to achieve ODS desulfurization.

Iso-Polyoxometalate [Mo8O26]4– (Mo8) Supported with Mesoporous Hexagonal Boron Nitride (h-BN): A Green and Efficient Composite Catalyst for Ultradeep Desulfurization of Model Fuel at Room Temperature

“…Among them, catalytic oxidation desulfurization (CODS) is considered the most promising industrial alternative to HDS. 8 Various new types of catalysts have been developed, such as MOF-based catalysts, 9 POM-based catalysts, 10 ionic liquid catalysts, 11 and metal phosphide catalysts. 12,13 Polyoxometalates (POMs) have the advantages of adjustable structure, diverse composition, easy synthesis, and high catalytic oxidation activity, 14 making POMs catalysts promising in the direction of catalytic oxidation desulfurization.…”

“…The limitations of traditional hydrodesulfurization (HDS) lie in the harsh reaction conditions, high costs, and difficulty in eliminating organic sulfur compounds such as thiophenes. , To overcome these limitations, new nonhydrogenation desulfurization technologies have been developed. Among them, catalytic oxidation desulfurization (CODS) is considered the most promising industrial alternative to HDS . Various new types of catalysts have been developed, such as MOF-based catalysts, POM-based catalysts, ionic liquid catalysts, and metal phosphide catalysts. , …”