ZnO基复合载体负载Ni催化剂催化噻吩加氢脱硫

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

用固相燃烧法制备了ZnO-A l2O3、ZnO-ZrO2、ZnO-TiO2三种复合氧化物载体,采用浸渍法制备了复合氧化物负载的镍催化剂,并考察其对噻吩加氢脱硫反应的催化性能。采用BET、NH3吸附红外光谱(IR)、程序升温脱附(TPD)、程序升温还原(TPR)、X射线衍射(XRD)等技术对催化剂进行表征。研究结果表明,复合氧化物载体负载的镍催化剂的催化活性明显高于ZnO单载体负载的催化剂;在三种复合氧化物负载的催化剂中,ZnO-ZrO2复合氧化物负载的催化剂活性最好,反应温度为400℃时噻吩转化率可达74%。与单载体相比,复合氧化物载体具有更大的比表面积,有利于活性组分的分散,其所负载的体相N iO更容易被还原,催化剂表面具有更多的吸附中心;除了N i/ZnO-ZrO2外,复合氧化物负载的催化剂具有更高的酸强度,从而有利于反应进行。尽管N i/ZnO-ZrO2催化剂的酸强度小于其他催化剂,但是ZnO-ZrO2载体的比表面积远大于其他复合氧化物载体,因而活性较好。

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.