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合成了La_(0.8)Sr_(0.2)Co_(0.6)M_(0.4)0_3系列和Ln_(0.6)Sr_(0.4)CoO_3系列单相钙钛矿型复合氧化物。用程序升温脱附法研究了置换金属离子对氧的吸附-脱附特性的影响,并考察了置换金属离子对CH_4,n-C_4H_(10)的完全氧化催化活性的影响。对于La_(0.8)Sr_(0.2)Co_(0.6)M_(0.4)0_3系列,氧的吸附-脱附特性由置换金属离子的价态和氧化还原性所决定。容易生成非常原子价态的金属离子的置换有利于氧在晶格氧空位上的吸附,催化活性受置换金属氧化物自身活性的影响。对于Ln_(0.6)Sr_(0.4)CoO_3系列,氧的吸附-脱附特性由稀土离子半径决定,离子半径小有利于氧的吸附,催化活性与吸附(脱附)氧量的变化规律一致。
The La_ (0.8) Sr_ (0.2) Co_ (0.6) M_ (0.4) 0_3 series and Ln_ (0.6) Sr_ (0.4) CoO_3 series single phase perovskite type oxides were synthesized. The temperature-dependent desorption method was used to study the effect of metal ions on the adsorption-desorption properties of oxygen. The effects of metal ions on the complete oxidation of CH_4 and n-C_4H_ (10) were investigated. For the La_ (0.8) Sr_ (0.2) Co_ (0.6) M_ (0.4) 0_3 series, the adsorption and desorption properties of oxygen are determined by the valence and redox properties of metal ions. The substitution of metal ions which are easy to generate valence valences favors the oxygen adsorption on the oxygen vacancies in the lattice and the catalytic activity is affected by the activity of the displaced metal oxide itself. For the Ln_ (0.6) Sr_ (0.4) CoO_3 series, the adsorption and desorption properties of oxygen are determined by the radius of rare earth ions. The small ion radius is favorable for the adsorption of oxygen. The catalytic activity is consistent with that of the adsorption / desorption of oxygen.