甲烷催化燃烧用LaMn/Al_2O_3催化剂研究

为获得具有优良低温活性的甲烷燃烧用催化剂,采用稀土La作为助剂制备了系列Mn基催化剂,借助X射线衍射(XRD)、X射线光电子能谱(XPS)和程序升温还原(TPR)技术对催化剂的结构进行了表征,并评价了其对甲烷燃烧的低温催化性能。结果表明,La助剂的添加显著促进了活性组分MnO2的分散,使其更易于还原,且使Mn4+和晶格氧富集于催化剂表面,因而显著提高了催化剂对甲烷催化燃烧的低温活性。当La质量分数为5%时,催化活性最高,甲烷50%转化率对应的温度较未加助剂时降低了70℃,且完全转化的温度低至480℃。

Study on catalytic combustion of methane over LaMn/Al 2O 3catalyst

In order to obtain more active catalysts for low-temperature methane combustion,the novel manganese-based catalysts promoted by lanthanum were prepared. The characteristics of the samples were investigated through X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) techniques. The low-temperature catalytic performances of these samples for methane combustion were studied. The results show that,with the addition of La promoter,the dispersion and reducibility of MnO2 are enhanced remarkably,Mn4+ and lattice oxygen are enriched on the catalyst surface. The low-temperature activities are improved significantly by the addition of lanthanum. The catalyst with La mass fraction of 5% exhibits the better activity,over which the temperature responding to 50% methane conversion is decreased by 70℃ than that of the MnO2/Al2O3 catalyst,and the methane conversion reaches 100% at 480 ℃ over this novel catalyst.