Enrichment of polymeric WOx species in WOx@SnO2 catalysts for ultra-deep oxidative desulfurization of liquid fuels

Designing an efficient and selective catalyst for the ultra-deep sulfur removal from liquid fuels under mild conditions is vibrant in environmental catalysis. This work reports the preparation of catalysts, i.e., WO x -based active sites generated on SnO 2 , for the sulfur removal from model diesel via biphasic oxidative desulfurization (ODS). The different active species generated on SnO 2 such as monomeric and polymeric WO x species, and crystalline WO 3 are characterized. Besides being the support, SnO 2 adsorbs the sulfur compounds from the oil phase and boosts the ODS performance. No significant change in the ODS activity of WO x @SnO 2 is observed in the presence of intrusive nitrogen and aromatic compounds. The order of ODS activity towards different sulfur compounds is dibenzothiophene (DBT) > 4,6-dimethyl DBT > benzothiophene. While using SnO 2 with a higher surface area (96.5 m 2 /g) instead of that with a lower surface area (19.2 m 2 /g), the formation of highly efficient polymeric WO x species is enhanced. Consequently, the turn over frequency is augmented from 10.99 to 43.23 h −1 , which is closely a 4-fold increase. The polymeric WO x species produced on SnO 2 having the higher surface area are visualized by HAADF-STEM analysis. Scalable preparation and the higher turnover frequency of the present catalyst can develop a promising catalytic system for the ODS.