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测定了10个含不同稀土Ln_(0.7)Sr_(0.3)MnO_3(Ln=La,Ce,Pr,Nd,Sm,Gd,Tb,Dy,Ho和Er)催化剂的TPD谱。从室温到1023K程序升温出现α,β,γ和θ四个脱附峰,从能量分析以及分别将473K、573K时的CO氧化转化率和TPD谱中α、β峰的峰温相关联,认为α峰(脱附峰温度为371K～431K)可能为O_2~-(吸),该氧物种为473K时CO氧化反应的主要活性氧物种;β峰(脱附峰温度为479～538K)可能为O~-(吸),该氧物种以α峰对应的氧物种为573K时CO氧化的主要活性氧物种;γ峰(脱附温度为921～929K)对应的氧物种可能为吸附在和锰离子连接的桥键晶格氧空位上的吸附氧物种O~(2-);而θ峰(脱附温度≥1023K)对应的氧物种为体相晶格氧,若该类O~(2-)脱附,会使结构坦塌。
The TPD spectra of 10 catalysts containing different rare earth Ln 0.7 Sr 0.3 MnO 3 (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) were determined. The four desorption peaks of α, β, γ and θ appeared from room temperature to 1023K. From the energy analysis and the correlation between CO oxidation conversion rates at 473K and 573K and the peak temperatures of α and β peaks in the TPD spectrum respectively, α peak (desorption peak temperature of 371K ~ 431K) may be O_2 ~ - (suction), the oxygen species is 473K CO oxidation reaction of the main reactive oxygen species; β peak (desorption peak temperature of 479 ~ 538K) may be The oxygen species corresponding to the α peak corresponds to the main oxygen species that is oxidized by CO at 573K. The oxygen species corresponding to the γ peak (desorption temperature of 921-929K) may be adsorbed on manganese ions O 2- (2-) is the oxygen species adsorbed on the bridging lattice oxygen vacancies, and the oxygen species corresponding to θ peak (desorption temperature ≥1023K) is the bulk phase oxygen. If the O 2- Desorption, the structure will collapse.