Influence of titanium oxide on the performance of molybdenum catalysts loaded on zeolite toward hydrodesulfurization reactions

Abstract

In this work, molybdenum, cobalt, and vanadium (MCV) based catalysts were loaded on zeolite Y (Z) and modified with different ratios of titanium oxide (0, 5 and 10%) as co-support (ZT). The catalysts were characterized using a scanning electron microscope (SEM), x-ray photoelectron spectroscopy (XPS), electron dispersive x-ray spectroscopy (EDX), powder x-ray diffraction (XRD), N2 adsorption-desorption isotherm, Fourier-transform infrared spectroscopy (FTIR), and temperature-programmed desorption (TPD). The prepared catalysts were evaluated for the hydrodesulfurization (HDS) reactions of dibenzothiophene (DBT). The incorporation of titania within the Z support was used to enhance the interaction between the active phases and the support surface through better distribution of the catalyst nanoparticles on the composite support. From the BET measurements, all of the catalysts exhibited the type IV isotherm with micro/mesoporous contributions. TPD was applied to illustrate the calcined catalyst acidity, which confirmed the positive role of titania in increasing the acidic strength of the catalyst. The XRD demonstrated the introduction of titania to the support which is clear from the characteristic peaks of titania. The elemental compositions of the catalyst and dispersion on the support surface were confirmed by EDX and x-ray mapping. The catalytic performance of 5% and 10% titania (ZT5-MCV and ZT5-MCV) showed higher activity compared to the control catalyst without titania (Z-MCV). A comparison of this catalyst with those reported in the literature points out that it is a promising candidate for fuel HDS.