Alida Elizabeth Cruz-Perez, Alfredo Guevara -Lara, Judith Pilar Morales-Ceron, Alejandro Alvarez-Hernandez, José Antonio de los Reyes, Laurence Massin, Christophe Geantet and Michel Vrinat, Catalysis Today, (2011), en prensa. doi:10.1016/j.physletb.2003.10.071, ISSN: 0920-5861, Factor de Impacto (2010): 3.526
In order to determine the species distribution at different steps of catalyst preparation, NiW/TiO2Al2O3 catalysts were prepared by aqueous impregnation with solutions at pH = 4 and 9, respectively. Raman and UVVis diffuse reflectance spectroscopies for NiW/TiO2Al2O3 precursors showed that during impregnation step Ni2+OhW12O4110? entities were formed for pH = 4 and 9. After calcination, Ni2+Oh/WO42? and Ni2+OhW12O4110? 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 NiW interaction, forming Ni2+OhW12O4110? precursor and consequently, an inefficient sulfidation. Besides, for catalyst impregnated at pH 4, Ni2+Oh/WO42? precursor underwent a more complete transformation to NiWS phase and led to a higher DBT HDS activity.