Synthesis of Titanium Modified Three-Dimensional KIT‑5 Mesoporous Support and Its Application of the Quinoline Hydrodenitrogenation

A series of Ti-KIT-5 materials with different ratios of Si/Ti were synthesized and employed as the supports to prepare the NiMo catalysts. All the modified supports and catalysts were measured by means of small-angle and wide-angle XRD, N₂ isotherm absorption–desorption, FTIR, XPS, Py-IR, and HRTEM techniques. The small-angle XRD and N₂ analysis characterization proved that the modified Ti-KT-x materials maintained the orderly mesoporous structure and displayed the larger pore size than the pure support. Additionally, results from the FTIR and XPS spectra demonstrated that Ti species were successfully embedded into the framework of KIT-5 material. It was noted that the introduction of suitable Ti species increased the amount of acid sites and promoted well distribution of the active metals. The hydrodenitrogenation performances of the NiMo/Ti-KT-x catalysts were evaluated under the reaction conditions of a H₂ pressure of 4 MPa, a WHSV of 10 h^–1, and different temperatures ranging from 340 to 400 °C. The modified NiMo/Ti-KIT-5 catalysts showed the higher catalytic activities than NiMo/KIT-5 catalyst, which was attributed to the larger pore size, more acid sites, and sulfide active metal species. Moreover, the NiMo/Ti-KT-20 catalyst showed the highest hydrodenitrogenation efficiencies (81.56%).