Oxidative desulfurization of model oil over the bowl-shaped N-doped carbon material loaded by the defective silicotungstic acid

Abstract

The Keggin-type silicotungstic acid (SiW12) with oxygen vacancies (Ov) defects was facilely supported on the bowl-shaped N-doped carbon (NC) material through the one-step carbonization of the precursor consisting of acryloxyethyl trimethylammonium chloride gel microspheres (CPDAC) and intact SiW12 in air. The catalyst SiW12/NC prepared at a calcination temperature of 400 °C showed an outstanding oxidative desulfurization (ODS) performance with H2O2, due to the Ov defect SiW12 with high activity and its excellent dispersion in NC as well as more exposed active sites. Consequently, dibenzothiophene (DBT) in model oil could be almost completely removed within 20 min at 60 °C with a high kinetic constant (0.2034 min−1) and low apparent activation energy (38.06 kJ/mol). In addition, based on the radical experiments, a HO radical mechanism for ODS reaction of model oil over SiW12/NC-400 was mainly uncovered. Furthermore, SiW12/NC-400 could be reused for 7 cycles with no significant loss of activity.