低浓度甲醇完全氧化钙钛矿型La1-xSrxMnO3催化剂研究

采用溶胶－凝胶法制备钙钛矿型复合氧化物Ｌａ１－ｘＳｒｘＭｎＯ３，研究其对低浓度甲醇完全氧化催化性能．实验结果表明：Ｓｒ２＋取代量和样品焙烧温度对催化剂活性均有显著影响，以８７３Ｋ焙烧的Ｌａ０．６Ｓｒ０．４ＭｎＯ３的催化活性为佳；催化剂的ＢＥＴ，ＸＰＳ，Ｏ２－ＴＰＤ，Ｈ２－ＴＰＲ表征研究结果证实，较大的比表面，较高的表面Ｍｎ浓度和氧吸附量都有利于催化剂活性的提高．

Study on Perovskite-Type La1-xSrxMnO3 Catalysts for Complete Oxidation of Low-Concentration Methanol

The perovskite type La 1-x Sr xMnO 3 catalysts were prepared by using sol gel method, and the catalytic activity for complete oxidation of methanol in low concentration was evaluated. The results showed that the partial substitution of Sr 2 for La 3 and the calcination temperature had pronounced effect on the performance of the catalyst for complete oxidation of methanol, with the activity of La 0.6 Sr 0.4 MnO 3 calcined at 873 K highest. XPS measurement demonstrated that enrichment of the A site metal elements at the surface occurred for all four La 0.6 Sr 0.4 MnO 3 samples calcined at temperatures of 873 1173 K, whereas the concentration of Mn 3 at the surface decreased with elevating calcination temperature. H 2 TPR testing indicated that the doping of Sr 2 brought about an increase in the amount of reducible Mn 3 . O 2 TPD measurement revealed that high calcination temperature would lead to decreasing in amounts of oxygen species adsorbed at the surface and descending in content of non stoichiometric oxygen in the bulk phase. The results in the present work indicated that the catalyst activity was closely related with the surface area of the catalyst and the concentration of Mn 3 at the surface, as well as the property of the surface oxygen species.