Silicotungstic acid-supported C@SiO2 nanospheres as an efficient oxidative desulfurization catalyst

Abstract

Keggin-type silicotungstic acid (SiW12)-supported on the silica gel microspheres modified with a thin carbon layer (SiW12@C@SiO2) was successfully synthesized through one-step in-situ pyrolysis of the precursor, which was consisted of a SiO2 core and a shell made up of cross-linked polyvinylimidazole (CPVI) and SiW12. The as-prepared SiW12@C@SiO2 catalyst showed an enhanced oxidative desulfurization (ODS) performance of dibenzothiophene (DBT) with H2O2 as oxidant. The defective SiW12 formed under the proper calcination temperature exposed the more active sites, so as to enhance its catalytic activity. In addition, the ODS performance was still promoted by the dispersed loading of the defective SiW12 on the carrier. Therefore, SiW12@C@SiO2 exhibited a higher kinetic constant (0.1621 min−1) and lower apparent activation energy (40.94 kJ/mol), and made 500 ppm of DBT removed completely at 60 °C within 20 min. More importantly, SiW12@C@SiO2 presented an excellent reusability.