Mesopore-encaged V-Mn oxides: Progressive insertion approach triggering reconstructed active sites to enhance catalytic oxidative desulfuration

Abstract The oxidative desulphurization (ODS) has become mainly popular by rapid catalytic oxidation of dibenzothiophene (DBT) relied on efficient heterogeneous catalyst. V-based catalytic active species were regarded as the potential option in the activity-preferred ODS systems. Herein, we reported the re-dispersion of vanadium oxide (VOx) on the mesoporous silica modified with manganese oxide (Mn3O4) through one progressive insertion approach of metal oxides in the silica. Impressively, mesopore-encaged vanadium-manganese oxides in the silica (VMn-MS) as the admirable output of excellent ODS catalyst was demonstrated compared to other monometal-modified counterparts and one-pot implanted one. The characterization results revealed the post-implanted VOx species not only deposited around the pre-covered Mn3O4 on the mesoporous surface but also inserted the surface layer of Mn3O4 inducing the amorphous evolution of aggregated Mn3O4 and the reconstruction of final active sites. This integrated approach made the reconstructed active species afford more exposed catalytic sites and the tailored surface redox cycles owing to the electronic communication of V-Mn. The catalytic results demonstrated the excellent catalytic desulphurization efficiency (∼100%) during 60 min at 80 °C, which made the sulphur content reduce to 6 mg·L-1, remarkably superior to other comparative samples. The outstanding catalytic performance of VMn-MS catalyst can be ascribed to the synergistic effect of V-Mn dual metals rendering two different reaction pathways, which includes free-radical reaction and ring-forming reaction, where Mn site acted as active center triggering reactive free radicals which could be further optimized by surrounded V sites around Mn sites to promote the ODS process.