Synthesis,Characterization And Catalytic Performance Of CuO-CeO₂/?-Al₂O₃ Catalysts

A serious of CuO-CeO₂/?-Al₂O₃ catalysts with different Cu/Ce ratio were synthesized by an improved amorphous citric precursor meththod,and investigated its catalytic performance of the catalyst at different temperature and ambient condition of the pyrolysis.The CuO-CeO₂/?-Al₂O₃ catalysts were characterized by XRD,XPS,H₂-TPR,BET and SEM techniques.The CO oxidation and oxygen storage capacity of the samples were evaluated in a continuous fixed bed reactor.The XRD patterns of the CuO-CeO₂/?-Al₂O₃ catalysts indicate that besides the diffraction peaks of crystalline?-Al₂O₃,the diffraction peaks appear at 28.555°and 56.335°corresponding to?111?and?311?planes of cubic ceria,respectively.No diffraction peaks of crystalline CuO are observed in the CuO-CeO₂/?-Al₂O₃ catalysts.Because of intergrowth and interaction between CuO and CeO₂,the Cu⁺species appear on the surface of CuO-CeO₂/?-Al₂O₃ catalyst and the Cu 2p_3/2 peaks shift to lower binding energy compared with that of the CuO/?-Al₂O₃ catalyst.H₂-TPR temperature of the samples pyrolysised in less oxygen atmosphere is lower than that in rich oxygen.The lowest H₂-TPR temperature is observed when the sample is synthesized under the Cu/Ce ratio being 7:3,the pyrolysis temperature being 230?and pyrolysis atmosphere being30%Air with 70%N₂.Compared with?-Al₂O₃ supporter,the CuO-CeO₂/?-Al₂O₃ catalyst shows a reduced BET surface area.The CuO-CeO₂/?-Al₂O₃ catalyst pyrolysised at 230?in less oxygen atomosphere with Cu/Ce ratio of 7:3 exhibits the preferable activity of catalytic CO oxidation and an excellent synergistic effect,which is consistent with the characterization results of the catalyst in microstructure and surface properties.