Designed formation of mesoscopical order of ionic liquid-based meso/macroporous Mo/TiO2 materials for high-performance oxidative desulfurization

Hierarchically structured ionic liquid-based Mo/TiO2 materials with three-dimensional ordered macroporous (3DOM) and short-ranged ordered mesoporous structure are synthesized by two steps self-assembling process and applied as catalysts in oxidative desulfurization (ODS) process. TG-DSC, SEM, TEM, XRD, BET, XPS, and FT-IR measurements demonstrate that as-fabricated catalysts possess ordered meso/macroporous structure with Mo species dispersed homogeneously on TiO2 matrix. In addition, the influences of sol-gelation temperatures and amount of nonionic surfactant on the mesoscopical order of catalyst are also discussed in detail. It can be demonstrated that catalyst prepared at mild sol-gel temperature (40 degrees C) and proper nonionic surfactant usage (3.0 g) exhibits the highest catalytic activity for aromatic sulfides. In the ODS reaction, 500 ppm of di-benzothiophene (DBT) in the model fuel can be completely removed within 100 min at 30 degrees C due to the well-designed ordered secondary mesopores and interconnected macroporous structure of catalyst, which provides rapid diffusion channels of reactant molecules to the inner surface and improves the exposure of Mo species on the mesoporous wall. Furthermore, as-synthesized catalyst can be reused for 15 runs without significant decrease in catalytic activity.