Study on TiO_2-Modified Pd/Al_2O_3 Catalyst for Selective Hydrogenation of Pyrolysis Gasoline

The TiO_2-modified Pd/Al_2O_3 (Pd/Al_2O_3-TiO_2) catalyst was prepared by impregnation and characterized by N_2 adsorption, XRD, SEM, FT-IR, TPD and TPR. The catalytic performance of the catalyst for selective hydrogenation of pyrolysis gasoline was studied. All the catalyst samples showed better performance compared with the reference catalyst used in industry. Taking account of convenience and flexibility of preparing Pd/Al_2O_3-TiO_2 catalyst, the suitable modification process should be done just only one time. The Pd/Al_2O_3-TiO_2 catalyst exhibited smaller surface area and lower surface acidity. The titania on alumina was extremely dispersed and concentrated in certain depth in the direction of cross section. The reduction of palladium oxide was more easily with the presence of titania in the Al_2O_3. The catalytic activity and selectivity of Pd/Al_2O_3-TiO_2 catalyst with composite oxide as a support were higher than Pd/Al_2O_3 catalyst with alumina alone as a support.