TiO2-ZrO2 Binary Oxides for Effective Hydrodesulfurization Catalysts

Abstract

Titania-zirconia mixed oxide was developed as support for Mo, CoMo and NiMo catalysts. Synthesis was carried out using evaporation induced self assembly and modified sol-gel templating route. The samples were calcined in a temperature range of 400 o C to 600 o C. SEM and porosity analyses were used to ensure that the mesostructure is stable after Mo and promoter incorporation. Wide-angle XRD was used to verify MoO3 (and MoS2) dispersion, which indicated crystallite size <40A up to 8wt% Mo loading. The IR spectral studies were used to determine the nature of Mo species (octahedral and tetrahedral). TPD study was used to determine the acidity of the supports. The physico-chemical properties were correlated with the catalytic hydrodesulfurization reaction. CoMo and NiMo catalysts were compared in order to gain an insight into the promoter effect on direct desulfurization pathways. A comparison with  -Al2O3, SBA-15 and KIT-6 supported catalysts shows much superior activities of mesoporous titania-zirconia supported catalysts which is attributed to favorable metal-support interactions in case of mesoporous titania-zirconia supported catalysts.