Restraining deactivation of hierarchical zeolite supported NiW catalysts in the HDS of thiophene†
NiW catalysts supported on γ-Al2O3 (NiW/Al2O3), commercial Beta (NiW/HB) and hierarchical Beta prepared by base–acid treatment (NiW/HB-M) were characterized by X-ray diffraction (XRD), N2 sorption, infrared spectroscopy (IR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic performance of these catalysts was evaluated in the hydrodesulfurization (HDS) of thiophene. The results indicate that NiW/HB as well as NiW/HB-M endured important and rapid deactivation showing that the introduction of additional mesopores/macropores in the support could not prevent the deactivation tendency. Interestingly, NiW/HB or NiW/HB-M mixed with NiW/Al2O3 and the utilization of Na+-exchanged Beta as a support remarkably improved the anti-deactivation ability of the catalysts. As a result, the catalysts NiW/NaB-M (NiW catalyst supported on Na+-exchanged hierarchical Beta) and NiW/20HB-M (20% NiW/HB-M mixed with 80% NiW/Al2O3) gave superior catalytic activity than NiW/Al2O3.