大比表面积La_(0.8)Sr_(0.2)CoO_3的制备及甲烷催化燃烧性能研究

Synthesis of La_(0.8)Sr_(0.2)CoO_3 with Large Surface Area and Its Application in Methane Combustion

采用丙氨酸溶液燃烧法、丙烯酰胺-丙氨酸法、丙烯酰胺-氨基乙酸法和环氧丙烷法制备了大比表面积钙钛矿型La0.8Sr0.2CoO3复合氧化物,研究了制备方法对复合氧化物结构和性能的影响,考察了其CH4催化燃烧活性,并运用XRD,FI-TR,BET,TPR等进行了表征。结果表明,制备方法对复合氧化物的性能有较大的影响,其中以丙氨酸溶液燃烧法制备的复合氧化物的比表面积较大(20.31 m2.g-1)和催化燃烧活性较好(T50和T100分别为470和550℃)。表征结果表明,该法所制复合氧化物的平均晶粒度较小,表面和氧空穴处的化学吸附氧更容易移动,表观活化能较低,这均有利于催化活性的提高。

A series of La0.8Sr0.2C0O3 catalysts with large surface area were prepared by different synthesis methods and tested for the catalysis of methane combustion. The selected techniques included the alanine solution combustion method, the polyacrylamide-alanine gel method, the polyacrylamide-glycine gel method and the epoxide gel method. The samples were characterized by means of XRD, FI-IR, BET and H2- TPR. The effects of preparation methods on structureand performance of La0.8Sr0.2C0O3 catalysts were studied. The results indicated that La0.8Sr0.2C0O3 catalyst prepared by alanine solution combustion method had higher catalytic activity for methane combustion, whose T50 and T100 were 470 and 550 ℃ respectively, which could be explained in terms of smaller average crystal size, higher specific surface are （20. 31 m^2·g^-1）, lower activation energy and easier mobile of chemical-adsorped oxygen in the surface and vacancy.