Ni and W interactions in the oxide and sulfide states on an Al2O3-TiO2 support and their effects on dibenzothiophene hydrodesulfurization

作者：Elizabeth Cruz Perez Alida; Guevara Lara Alfredo^*; Pilar Morales Ceron Judith; Alvarez Hernandez Alejandro; Antonio de los Reyes Jose; Massin Laurence; Geantet Christophe; Vrinat Michel

来源：Catalysis Today, 2011, 172(1): 203-208.

DOI：10.1016/j.cattod.2011.03.027

• DBT HDS
• Ni-W catalysts
• Ni2+-W12O4110- heteropolyoxometalate
• TiO2-Al2O3

In order to determine the species distribution at different steps of catalyst preparation, NiW/TiO2-Al2O3 catalysts were prepared by aqueous impregnation with solutions at pH = 4 and 9, respectively. Raman and UV-Vis diffuse reflectance spectroscopies for Ni-W/TiO2-Al2O3 precursors showed that during impregnation step Ni-Oh(2+)-W12O4110- entities were formed for pH = 4 and 9. After calcination, Ni-Oh(2+)/WO42- and Ni-Oh(2+)-W12O4110- species were identified for solids synthesized at pH = 4 and at pH = 9, respectively. Calcined catalyst impregnated at pH 4 displayed the highest Dibenzothiophene (DBT) hydrodesulfurization (HDS) activity for this series. This high activity was related to a higher concentration for the NiWS phase for the catalyst prepared at pH = 4 than that at pH = 9, as evidenced by X-ray photoelectron spectroscopy (XPS). It could be suggested that impregnation at pH = 9 allowed a high Ni-W interaction, forming Ni-Oh(2+)-W12O4110- precursor and consequently, an inefficient sulfidation. Besides, for catalyst impregnated at pH 4, Ni-Oh(2+)/WO42- precursor underwent a more complete transformation to NiWS phase and led to a higher DBT HDS activity.

• 出版日期2011-8-25