稀土A-Ce-O催化剂的合成及性能研究

Synthesis and Catalytic Performance of Rare-Earth Composite Oxide Catalysts

采用改进的溶胶-凝胶法合成出了几种含铈稀土复合氧化物催化剂,运用XRD,IR等不同测试手段对复合氧化物催化剂进行了表征,测试了甲烷催化燃烧活性。XRD分析结果表明:经1200℃焙烧3 h后4种催化剂中Ba-Ce-O,Sr-Ce-O主要以单一相钙钛矿结构BaCeO3和SrCeO3的形式存在,La-Ce-O体系催化剂呈现面心立方晶体结构特征衍射峰,与立方结构CeO2的衍射峰相似,只是峰的位置偏向低角度;Mg-Ce-O主要以简单氧化物CeO2的相存在,在甲烷催化燃烧反应中La-Ce-O显示出了良好的催化活性,T10为510℃,T90为670℃;主相为SrCeO3的Sr-Ce-O体系催化剂的甲烷催化活性最差,T10为570℃,T90为743℃。

Rare-earth composite oxide catalysts were prepared by the sol-gel method with circumfluence using glucose as a complex agent.The structure and catalytic properties were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR) and catalytic activities for the combustion of methane.It is shown that the single phase perovskite BaCeO_3 and SrCeO_3 obtained for two catalysts Ba-Ce-O and Sr-Ce-O system respectively after calcined at 1200 ℃ for 3 h.La-Ce-O system catalyst shows cubic structure CeO_2,but there diffraction peak is near low angle,which shows higher catalytic activity for methane combustion(Temperature of methane conversion 10% is 510 ℃,temperature of methane conversion 90% is 670 ℃) than three other systems.Major CeO_2 phase and minor MgO phase exist in Mg-Ce-O system catalyst,which show secondary catalytic activities,however,the single phase SrCeO_3 exists in Sr-Ce-O system catalyst shows lowest catalytic activity(Temperature of methane conversion 10% is 570 ℃,temperature of methane conversion 90% is 743 ℃) in methane catalytic combustion.