NiW Catalysts Supported Ti-Modified KIT-6 for the Hydrodesulfurization of Dibenzothiophene

Abstract NiW catalysts supported on KIT-6 and Ti-modified KIT-6 mesoporous silicas were synthesized and evaluated for the hydrodesulfurization (HDS) of dibenzothiophene to investigate the effect of titanium incorporation on the catalyst’s structure and performance. Titanium was introduced into the KIT-6 support using Si/Ti molar ratios of 60 and 40, leading to the formation of predominantly framework Ti–O–Si species at lower Ti content and additional extra-framework TiOx species at higher Ti loading. X-ray diffraction, FTIR-ATR, and N₂ physisorption analyses confirmed that the ordered cubic mesoporous structure of KIT-6 was preserved after Ti incorporation and metal impregnation. However, significant changes in surface area and pore diameter were observed. Transmission electron microscopy revealed that Ti addition reduced the slab length and stacking number of WS₂ crystallites, thereby improving the dispersion of the active phase. Catalytic evaluation showed that the unmodified NiW/KIT-6 catalyst exhibited the highest HDS activity. In contrast, Ti-modified catalysts displayed slightly lower reaction rates despite enhanced dispersion, which is attributed to changes in pore accessibility and metal–support interactions. All catalysts predominantly followed the direct desulfurization pathway, with Ti incorporation promoting a moderate increase in the hydrogenation route. These results demonstrate that Ti-modified KIT-6 influences the balance between dispersion, accessibility, and selectivity in NiW catalysts for dibenzothiophene hydrodesulfurization. Graphical Abstract Titanium modification of KIT-6 supports alters WS 2 dispersion, pore accessibility, and the balance between direct desulfurization and hydrogenation pathways in NiW catalysts for dibenzothiophene hydrodesulfurization.