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

NiS2//MoS2 catalysts with different Ni/Mo molar ratios were prepared by two-step hydrothermal method, i.e., MoS2 was firstly synthesized and then NiS2 was prepared and deposited on the surface of MoS2. 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 NiS2 and MoS2 phases rather than Ni-Mo-S phase existed in NiS2//MoS2 catalysts. In the HDO of p-cresol, NiS2 acted as a donor phase to provide spillover hydrogen, which migrated to MoS2 for reaction. Because of the particular synthesis procedure, NiS2//MoS2 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 degrees C for 4 h, respectively. The hydrogenation activity was enhanced in the presence of NiS2, leading to the increases on both methylcyclohexane selectivity and deoxygenation degree. NiS2//MoS2 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. (C) 2016 Elsevier Ltd. All rights reserved.