DOI: 10.1002/cctc.201300521 Tuning Hydrodesulfurization Active-Phase Dispersion using Optimized Mesoporous Titania-Doped Silica Supports Minh Tuan Nguyen Dinh, [a] Prashant Rajbhandari, [a] Christine Lancelot,* [a] Pascal Blanchard, [a] Carole Lamonier, [a] Magali Bonne, [c] SØbastien Royer, [d] Franck Dumeignil, [a, b] and Edmond Payen [a] Introduction The S-containing compounds present in transportation fuels are responsible for a substantial degradation of air quality. Fur- thermore, they are strong poisons of the catalysts used in vehi- cle exhaust gas converters. Consequently, as the legal limita- tions on the S content have become increasingly stringent, a drastic improvement in the hydrodesulfurisation (HDS) of pe- troleum feedstocks is necessary. Such a catalytic process is most generally performed by using CoMo/Al 2 O 3 catalysts. The active phase consists of well-dispersed MoS 2 nano-crystallites decorated with Co promoter atoms. Although Al 2 O 3 is the most commonly used support, the HDS performances of the catalysts are known to strongly depend on the nature of the support. [1–5] Meso-structured oxides offer further perspectives for catalytic applications: they exhibit various advantages such as a particularly high specific surface area (SSA) with a pore size in the meso-pore range, which can be easily tailored (typi- cally between 2 and 15 nm). Some meso-structured SiO 2 -based materials have been studied extensively as HDS catalyst sup- ports, such as SBA, [6–11] MCM-41, [12, 13] HMS [14, 15] and KIT-6. [16] Among these materials, SBA-15 has attracted considerable at- tention because of its adequate textural properties with a pore diameter in the 3–30 nm range, which is larger than that of MCM-41 and HMS. Sampieri et al. found that Mo-based cata- lysts supported on SBA-15 exhibited higher activity in the HDS of dibenzothiophene than MCM-41-supported catalysts, which was assigned to the confinement of MoS 2 particles within the porous structure of the materials. [17] Furthermore, a SBA pore wall thickness of around 3–6 nm provides a higher thermal sta- bility than that of MCM-41, which is a necessary property for reactions performed under harsh temperature and pressure conditions. The modification of the SiO 2 properties was also considered by the addition of elements such as Al, [18–24] Zr [25–30] and Ti [31–33] grafted onto the surface or incorporated into the walls of the SiO 2 before the deposition of the HDS active- phase precursors. Furthermore, the incorporation of Ti within the SBA structure was attempted by several groups, with Si/Ti ratios between 80 and 20. [34–37] However, the incorporated amounts were quite low, and the highest incorporated TiO 2 content was 6.2 wt % (Si/Ti = 20). The Ti-containing supports appeared to be more active than their Ti-free counterparts in thiophene HDS, [34] dibenzothiophene (DBT) HDS [35, 36] and bi- phenyl hydrogenation. [37] The authors attributed these im- proved performances to an increase in the metal–support in- Solids composed of TiO 2 nano-crystallites (10–40 wt %) dis- persed in an SBA-15 matrix were synthesised and used as hy- drodesulfurisation (HDS) active-phase supports. Well-dispersed polymolybdate species were detected by Raman spectroscopy on all the CoMo-based oxidic precursors. Undesirable bulk CoMoO 4 mixed oxide was also detected on the surface of low- TiO 2 -content materials, which suggests the enhancement of the Mo oxidic species dispersion as a result of the presence of TiO 2 . After activation under H 2 /H 2 S, the obtained catalysts were tested in the HDS of thiophene. An optimum conversion was observed for the catalyst supported on the solid that con- tained 20 wt % TiO 2 , which outperformed the homologous samples supported on TiO 2 and SBA-15. This clearly highlights the beneficial effect of using such nano-TiO 2 -SBA-15 composite supports, in which SBA-15 confers adequate textural properties to the system, and the active phase benefits from the disper- sive effect of TiO 2 . [a] Dr. M. T. Nguyen Dinh, Dr. P. Rajbhandari, Dr. C. Lancelot, Dr. P. Blanchard, Prof. C. Lamonier, Prof. F. Dumeignil, Prof. E. Payen UnitØ de Catalyse et Chimie du Solide, UCCS, UMR CNRS 8181 UniversitØ Lille Nord de France 59655 Villeneuve d’Ascq (France) Fax: (+ 33) 3-20-43-65-61 E-mail : christine.lancelot@univ-lille1.fr [b] Prof. F. Dumeignil Institut Universitaire de France Maison des UniversitØs 103 Bd Saint-Michel, 75005 Paris (France) [c] Dr. M. Bonne Institut de Science des MatØriaux de Mulhouse IS2 M UMR 7361 CNRS 3 bis, rue Alfred Werner, 68093 Mulhouse Cedex (France) [d] Dr. S. Royer UniversitØ de Poitiers IC2 MP UMR 7285 CNRS 4, rue Michel Brunet, 86022 Poitiers Cedex (France)  2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim ChemCatChem 2014, 6, 328 – 338 328 CHEMCATCHEM FULL PAPERS