Promotion of oxidative desulfurization performance of model fuel by 3DOM Ce-doped HPW/TiO2 material

Abstract

Phosphotungstic acid (HPW) supported on Ce-doped three-dimensional ordered macroporous (3DOM) TiO2 catalysts are studied in catalytic oxidation desulfurization (ODS) of model oil. The structural and textural of as-synthesized catalysts are characterized by N2 adsorption, XRD, Raman spectroscopy, SEM-EDS, TEM, FT-IR, XPS, UV–Vis and ICP. These results upheld the existence of periodically arranged macroporous structure of catalyst, with Keggin-type of HPW dispersed homogeneously on TiO2 matrix. Among these 3DOM Ce-doped HPW/TiO2 materials, catalyst with 15 wt.% cerium dosage exhibits best ODS performance, which oxidized 99.8% of dibenzothiophene (DBT) into corresponding sulfone within 40 min. The excellent ODS performance of 3DOM Ce-doped HPW/TiO2 catalyst is related to the common influence of more oxygen vacancies produced by electron transformation between Ce3+ and Ce4+. The chemisorbed oxygen on the surface catalyst will facilitate the selective oxidation of sulfides to sulfones. Moreover, the 3DOM structure of catalyst will further promote the mass transfer of reactants and products on the pore channel. The as-prepared catalyst shows excellent reusability in the ODS system, no obviously decrease in catalytic activity even after 6 runs.