Pd-CeO2/Al2O3结构对其催化加氢脱硫反应性能的影响

Pd-CeO2/Al2O3 catalysts with different Pd contents were prepared by stageimpregnation; their performances in hydrodesulfurization (HDS) of thiophene were investigated. XRD, H2-TPR, NH3-TPD, hydrogen and CO chemisorption were used to characterize the catalyst structure. The results show that Pd precursor is deposited favorably on CeO2 surface; new acid sites are produced due to the interface effect from the PdCe interaction. The highest promoting effect of Pd-Ce interaction is observed on the Pd-CeO2/Al2O3 catalyst with a Pd content of 2%, which exhibits highest interface acidic amounts per unit Pd. Pd(111) face is the predominant face, which brings on the strong PdCe interaction and interface effect. As to PdCeO2/Al2O3 catalysts with 1% and 4% Pd content, the space structure of Pd-Ce interaction inhibited the interface effect; hence the promoting effect was not so distinct.