Effect of TiO2 on the hydrodesulfurization performance of bulk Ni2P

The bulk Ni2P and TiO2-doped bulk Ni2P (Ti-Ni2P(x), x represents the Ti/Ni atomic ratio) were prepared by a co-precipitation method followed by an in-situ H-2 temperature-programmed reduction procedure. The passivated catalysts were characterized by N-2 adsorption-desorption method and X-ray absorption spectroscopy (XAS). Their hydrodesulfurization (HDS) performances were studied using dibenzothiophene (DBT) as the model molecule. The XAS results indicated that Ti-Ni2P(0.01) and Ti-Ni2P(0.03) were more oxidized than the other samples during passivation. The EXAFS analysis showed that Ni was formed in the presence of TiO2. The coordination number of Ni-Ni shell of Ni in Ti-Ni2P(x) reached its maximum at a Ti/Ni atomic ratio = 0.05. The HDS activity of Ni2P was substantially improved by the introduction of TiO2. TiO2 had different promoting effects on the direct desulfurization pathway and the hydrogenation pathway activities of Ni2P. The promoting effect of TiO2 is discussed by considering the electronic interactions between surface TiO2 and Ni2P species and the variations in the active site distributions. (C) 2011 Elsevier B.V. All rights reserved.