La_(0.8)K_(0.2)Mn_(0.95)Cu_(0.05)O_3在含SO_2气氛下氧化模拟炭烟的性能

Performance of La_(0.8)K_(0.2)Mn_(0.95)Cu_(0.05)O_3 in oxidizing model soot in atmosphere mixed with SO_2

采用柠檬酸络合法合成La0.8K0.2Mn0.95Cu0.05O3钙钛矿型催化剂,并用浸渍法、络合法、混合法制备了系列担载型催化剂La0.8K0.2Mn0.95Cu0.05O3/γ-Al2O3。运用程序升温氧化(TPO)对未担载及不同担载量下的催化剂进行了活性评价,并考察了在不同浓度的SO2气氛下催化剂氧化模拟炭烟的性能,采用XRD、BET和FT-IR对催化剂进行了表征。XRD和BET测试结果显示,担载前催化剂具有良好的钙钛矿结构,担载后催化剂的比表面积增大;TPO测试表明浸渍法制备担载量为20%的催化剂表现了更好的催化活性。未担载的催化剂活性较高,但催化剂担载后耐硫性能得到提高。FT-IR证实了随着SO2浓度的升高催化剂表面产生的硫酸盐物种逐渐积累从而抑制了催化剂的活性。

La0.8K0.2Mn0.95Cu0.05O3 perovskite-type oxide was synthesized by the complex method of citric acid,then was supported on γ-Al2O3 to obtain a series of loadings by using the impregnation method,complexing method and mixing method.Temperature programmed oxidation （TPO） was used to investigate their catalytic behavior of model soot oxidation in a feed gas containing various concentrations of SO2.The catalysts were characterized with XRD,BET,and FT-IR.XRD and BET results showed that the catalysts exhibited good structure of perovskite-type before being supported,and the specific surface area increased after being supported.TPO tests revealed that the activity of La0.8K0.2Mn0.95Cu0.05O3/γ-Al2O3 prepared by the impregnation method with 20%（mass） loading was better.La0.8K0.2 Mn0.95Cu0.05O3 catalyst presented higher catalytic activity than those supported ones,i.e.La0.8K0.2Mn0.95Cu0.05O3/γ-Al2O3,however,sulfur-resistance of catalysts was improved when supported on γ-Al2O3.FT-IR spectrum confirmed that with increasing concentration of SO2,the SO2-4 species formed and accumulated on the catalyst surface would inhibit the catalytic activity.