Comparison of four different synthetic routes of Ni2P/TiO2–Al2O3 catalysts for hydrodesulfurization of dibenzothiophene

Abstract

Ni₂P/TiO₂–Al₂O₃ is a very promising hydrodesulfurization catalyst, however the catalysts reported so far all use the temperature-programmed reduction (H₂-TPR) method and the reduction temperature can be as high as 973 K. It is important to develop more feasible methods to prepare this material. Herein, Ni₂P/TiO₂–Al₂O₃ catalysts were successfully synthesized at a low reduction temperature (573 K) based on NiCl₂·6H₂O and NH₄H₂PO₂ (method I). Three other methods were also used to prepare the Ni–P/TiO₂–Al₂O₃ catalysts in this work. The catalysts were characterized using XRD, TEM, FT-IR, XPS, CO uptake, and N₂ sorption measurements. Experimental results indicate that the preparation method had a major influence on the physicochemical properties of the catalysts and the HDS activity. Among the four methods examined, method I could more effectively suppress the formation of AlPO₄ and favor the formation of Ni₂P, which can be attributed to the relatively low reduction temperature and the flowing hydrogen used in this method. The hydrodesulfurization activity results indicate that the Ni₂P/TiO₂–Al₂O₃ catalyst prepared by method I gave a high HDS conversion of 100.0% at a reaction temperature of 583 K. The results suggest that method I provides a simple and energy-efficient route for the preparation of the Ni₂P/TiO₂–Al₂O₃ catalyst with excellent catalytic performance for the HDS of dibenzothiophene.