Tuning Hydrodesulfurization Active-Phase Dispersion using Optimized Mesoporous Titania-Doped Silica Supports

摘要

Solids composed of TiO2 nano-crystallites (10-40wt%) dispersed in an SBA-15 matrix were synthesised and used as hydrodesulfurisation (HDS) active-phase supports. Well-dispersed polymolybdate species were detected by Raman spectroscopy on all the CoMo-based oxidic precursors. Undesirable bulk CoMoO4 mixed oxide was also detected on the surface of low-TiO2-content materials, which suggests the enhancement of the Mo oxidic species dispersion as a result of the presence of TiO2. After activation under H-2/H2S, the obtained catalysts were tested in the HDS of thiophene. An optimum conversion was observed for the catalyst supported on the solid that contained 20wt% TiO2, which outperformed the homologous samples supported on TiO2 and SBA-15. This clearly highlights the beneficial effect of using such nano-TiO2-SBA-15 composite supports, in which SBA-15 confers adequate textural properties to the system, and the active phase benefits from the dispersive effect of TiO2.