The Study Of Pd-Fe Bimetallic Catalysts For CO Oxidation

The Pd-M/Fe(OH)x (M=Ce, La, Cu, Mn, Sn) catalysts were prepared by co-precipitation menthod. The results reveal that the catalytic activity of Pd/Fe(OH)x catalyst is the best. Then Pd-Fe-Ox/Al2O3 catalysts were prepared by co-impregnation (co-Pd-Fe-Ox/Al2O3) and sol-gel method (sol-gel-Pd-Fe-Ox/Al2O3), and characterized by BET, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The temperatures of 100% conversion for CO oxidation (T100) over reduced co-Pd-Fe-Ox/Al2O3 and sol-gel-Pd-Fe-Ox/Al2O3 are 90 and 25℃for 1% CO/Air, respectively. XRD results indicate that the sol-gel method is favorable for the more highly dispersion of PdO particles compared with simultaneous wet impregnation method. H2-TPR results suggest that the interaction between Pd and Fe is existent over both sol-gel-Pd-Fe-Ox/Al2O3 and co-Pd-Fe-Ox/Al2O3 catalysts, and the interaction over former catalyst is stronger than that over latter catalyst. The XPS results show that the surface Pd species are the mixture of oxide and metal state for reduced sol-gel-Pd-Fe-Ox/Al2O3 and reduced co-Pd-Fe-Ox/Al2O3 catalysts, leading to the high activity for CO oxidation. Furthermore, the different Pd2+/Pd0 value accounts for the different activity of reduced and reduced co-Pd-Fe-Ox/Al2O3 catalysts.The influce of Fe content over sol-gel-Pd-Fe-Ox/Al2O3 catalysts for CO oxidation was also investigated in this paper. T100 over sol-gel-Pd-Fe-Ox/Al2O3 (Pd wt.%=1%, Fe wt.%=13.86%)catalyst is 25℃for 1% CO/Air. The characterized results indicate the introducing Fe would increase the interaction between Pd and Fe, and stabilize PdO species.