镁掺杂对LaCrO_3催化剂的结构和性能的影响

Effects of Magnesium Doped on Structure and Performance of LaCrO_3 Catalysts

以柠檬酸为络合剂采用溶胶-凝胶法制备了纯LaCrO3和镁掺杂型催化剂,以X射线衍射法分析各样品的物相,以BET法测定各样品的表面积,用TPR技术表征了各样品的还原性能,以甲烷燃烧为探针反应考察各样品的催化氧化活性。实验结果表明:未掺杂镁的样品为单一相钙钛矿LaCrO3结构。镁的掺杂即可破坏单相钙钛矿LaCrO3结构的形成,明显削弱了其衍射峰强度,同时产生了LaCrO4和La2CrO6及MgO 物相,但可以促使产物以细小晶粒相互分散,提高了催化剂的比表面积和还原能力,改善了其催化活性。当镁的加入量为10％时催化活性最好,细化功能最强,比表面积最大。

A series of chromium-containing rare earth composite oxide catalysts were synthesized by sol-gel method. The catalysts were characterized by means of XRD, TPR, BET and the activity of methane Combustion . The results of the tests reveal that the Mg doped affects the structure of the LaCrO3 catalysts and decries the diffracted intensity of the LaCrO3 catalysts so that all the complexes exist as mixture phases such as LaCrO4 La2CrO6 and MgO, but magnesium can promote the dispersion of the products as fine particles. The Mg doped can increase the reduce performance and the specific surface area of the catalysts. The activity of the catalysts is the best and specific surface area of the catalysts is the most high when the Mg doped is 10% . At the same time, the ultra-fine function of the catalysts is strengthened.