Construction of biomimetic catalysis system coupling polyoxometalates with deep eutectic solvents for selective aerobic oxidation desulfurization

Designing green and efficient catalytic system under extremely mild conditions with high atom economy is always desired in practical applications. In this study, an innovative and efficient biomimetic catalytic system coupling polyoxometalate (POM, Anderson-type Na3H6CrMo6O24) with deep eutectic solvents (DESs) is proposed. This coupled system is applied for oxidation desulfurization, which exhibited extraordinary desulfurization performances at the extremely low temperature of 60 °C with the ambient pressure using oxygen as the oxidant. The desulfurization process follows the extraction-oxidation mechanism, during which POM severed as the electron transfer mediator is essential for highly efficient aerobic oxidation desulfurization. The deactivation of this catalytic system after reuse for four times was likely derived from the transformation of Na3H6CrMo6O24 POM crystal structure. In addition, the incomparable desulfurization performances of this biomimetic system in commercially available diesel further strongly confirm the potential application on an industrial scale. More importantly, this work is helpful in the precisely design and development of biomimetic coupled systems for catalytic applications under extremely mild conditions.