Properties of Ni Supported on ZnO-based Mixed Oxides for Hydrodesulfurization of Thiophene

Three kinds of mixed oxides ZnO-Al2O3,ZnO-ZrO2 and ZnO-TiO2 were prepared by solid state combustion method.Ni catalysts supported on the mixed oxides were prepared by impregnation and hydrodesulfurization of thiophene(HDS) was selected as probe to study their catalytic property.The samples were characterized by BET,infrared after adsorpted NH3(IR),temperature programmed desorption(TPD),temperature programmed reduction(TPR) and X-ray diffraction(XRD).The results indicated that the activities of the catalysts supported on the mixed oxides were higher than that of Ni/ZnO;Ni/ZnO-ZrO2 exhibited the highest activity among the three catalysts supported on the mixed oxides,and the conversion of thiophene over it was 74% at 400 ℃.Compared with ZnO,mixed oxides had relatively high surface area,which was favored of dispersion of active component.As a result,NiO over the mixed oxides was reduced more easily,more adsorption sites existed over the surface of Ni/mixed oxides,and the acid strength of them was stronger expect Ni/ZnO-ZrO2.Although the acid strength of Ni/ZnO-ZrO2 was lower than the others,the surface area of ZnO-ZrO2 was much larger than those of the other supports,resulting that had better performance for HDS of thiophene.