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The effects of ceria and zirconium oxides additions to alumina-supported palladium catalysts on methane combustion behavior were investigated. The structure and TPR/TPO properties were studied by XRD, TPR, TPO techniques. The results show that the addition of Ce-Zr oxides improves the thermal stability of alumina and PdO. The Pd/Ce_ 0.2Zr_ 0.8/Al_2O_3 exhibits the highest activity and thermal stability for methane combustion. The addition of Ce-Zr oxides improves the thermal stability of the catalysts in line with its effects of preventing γ→α-Al_2O_3 phase transition and improving the temperature of the PdO decomposition. For the catalysts calcined at 1100 ℃, the presence of Ce-Zr oxides is of great benefit to the reduction of PdO and increases the catalytic activity of the catalysts (Decreases T_ 20% and T_ 90%). Pd/Ce_ 0.2Zr_ 0.8/Al_2O_3 exhibits the highest activity and thermal stability for methane oxidation. The temperatures for the 90% methane conversion are 448 and 455 ℃ for the Pd/Ce_ 0.2Zr_ 0.8/Al_2O_3 catalysts calcined at 500 and 1100 ℃, respectively.
The results of ceria and zirconium oxides additions to alumina-supported palladium catalysts on methane combustion behavior were investigated. The structure and TPR / TPO properties were studied by XRD, TPR, TPO techniques. the thermal stability of alumina and PdO. The Pd / Ce 0.2Zr 0.8 / Al 2 O 3 exhibits the highest activity and thermal stability for methane combustion. The addition of Ce-Zr oxides improves the thermal stability of the catalysts in line with its effects of preventing γ → α-Al_2O_3 phase transition and improving the temperature of the PdO decomposition. For the catalysts calcined at 1100 ° C, the presence of Ce-Zr oxides is of great benefit to the reduction of PdO and increases the catalytic activity of the catalysts (Decreases T_ 20% and T_90%). Pd / Ce 0.2Zr 0.8 / Al 2 O 3 exhibits the highest activity and thermal stability for methane oxidation. The temperatures for the 90% methane conversion are 448 and 455 for the Pd / Ce_ 0.2Zr_ 0.8 / Al_2O_3 catalysts calcined at 500 and 1100 ℃, respectively.