Preparation of NiS2//MoS2 catalysts by two-step hydrothermal method and their enhanced activity for hydrodeoxygenation of p-cresol.

NiS 2 //MoS 2 catalysts with different Ni/Mo molar ratios were prepared by two-step hydrothermal method, i.e., MoS 2 was firstly synthesized and then NiS 2 was prepared and deposited on the surface of MoS 2 . The resultant catalysts were characterized by XRD, XPS, TEM, SEM, N 2 physisorption and their activities were tested using the hydrodeoxygenation of p -cresol as a probe. The results showed that separated NiS 2 and MoS 2 phases rather than Ni–Mo–S phase existed in NiS 2 //MoS 2 catalysts. In the HDO of p -cresol, NiS 2 acted as a donor phase to provide spillover hydrogen, which migrated to MoS 2 for reaction. Because of the particular synthesis procedure, NiS 2 //MoS 2 had higher surface area to expose more active sites. When Ni/Mo molar ratio was adjusted to 0.3, p -cresol conversion and the deoxygenation degree reached to 98.5% and 95.4% at 275 °C for 4 h, respectively. The hydrogenation activity was enhanced in the presence of NiS 2 , leading to the increases on both methylcyclohexane selectivity and deoxygenation degree. NiS 2 //MoS 2 catalysts prepared by this two-step synthesis method exhibited higher hydrodeoxygenation activity than that by other methods, presenting a good potential of this method for the synthesis of other bi-component sulfides with high catalytic activity. [ABSTRACT FROM AUTHOR]