Ag/La0.6Sr0.4MnO3基催化剂上CH3OH和CO的完全氧化

合成了Ａｇ／Ｌａ０．６Ｓｒ０．４ＭｎＯ３、Ａｇ／Ｌａ０．６Ｓｒ０．４ＭｎＯ３／γ－ＡＩ２Ｏ３两毓催化剂，发现钙钛矿型Ｌａ０．６Ｓｒ０．４ＭｎＯ３对低浓度ＣＨ３ＯＨ或ＣＯ的完全氧化显示出相当高的催化活性，适量Ａｇ对钙钛矿型Ｌａ０．６Ｓ５０．４ＭｎＯ３基质的修使其对ＣＨ３ＯＨ或ＣＯ完全氧化催化活性获明显提高；在６％Ａｇ／２０％Ｌａ０．６Ｓｒ０．４ＭｎＯ３／γ－ＡＩ２Ｏ３催化剂 ，ＣＨ３ＯＨ完全氧化的Ｔ

COMPLETE OXIDATION OF CH3OH AND CO AT LOW CONCENTRATIONS OVER Ag/La0.6Sr0.4MnO3-BASED CATALYSTS

The Ag/La0.6Sr0.4MnO3 and Ag/La0.6Sr0.4MnO3/γ-Al2O3 catalysts were prepared and their catalytic performance for complete oxidation of CH3OH and CO at low concentrations were evaluated. The results showed that the La0.6Sr0.4MnO3 catalyst displayed considerably high catalytic activities for complete oxidation of CH3OH and CO at low concentrations and that 6%Ag-modification to La0.6Sr0.4MnO3 host catalyst resulted in the enhancement of the activities for the catalytic complete oxidation of CH3OH and CO, decreasing the T95 (the reaction temperatures required for the conversion of 95% CH3OH or CO) to 421 and 370K from 465 and 420K for the corresponding Ag-unmodified system, respectively. Over a 6%Ag/20%La0.6Sr0.4MnO3/γ-Al2O3 catalyst, T95 temperature for the CH3OH oxidation was further lowered to 413K, and even at so low reaction temperatures the contents of HCHO and CO in the reaction-exit gas were under the GC-detectable limits, while over the 0.1%Pd/γ-Al2O3 and 0.1%Pt/γ-Al2O3 catalysts the contents of HCHO in the reaction-exit gases remained at the levels of about 200×10-6 and 630×10-6 at their T95 temperatures respectively. The nature of interaction of Ag-dopant with the surface of the La0.6Sr0.4MnO3 host catalyst with the perovskite structure was discussed together with the results of XRD, XPS and H2-TPR characterizations of the catalysts.