论文部分内容阅读
采用柠檬酸溶胶-凝胶法制备钙钛矿型La0.6Sr0.4MnO3 氧化物, 并用Ag 对其进行修饰,制得Ag/La0.6Sr0.4MnO3 催化剂.活性评价结果显示, Ag 的修饰能显著提高原基质催化剂La0.6Sr0.4MnO3 对低浓度CH3OH和CO完全氧化的催化活性, 相应于95% CH3OH和CO转化所需反应温度T95分别可低至421 和370 K. 催化剂的XPS和LRS谱学表征结果揭示, 在6% Ag/La0.6Sr0.4MnO3上, 具高度反应活性的表面氧物种O22- (a)和O-(a)在总表面氧中所占克分子百分数(m ol% )几近未经Ag 修饰的基质体系La0.6Sr0.4MnO3 的两倍. O2-TPD测试结果证实,Ag 对La0.6Sr0.4MnO3基质的修饰、掺杂和部分取代使其对O2 的低温吸附能力大为提高,诱生出一类数量可观具有低温吸-脱附性能的吸附氧物种. 本文结果表明, Ag/La0.6Sr0.4MnO3 催化剂对CH3OH和CO完全氧化高的催化活性与Ag 的修饰提高了催化剂对氧的低温吸附活化能力, 并使催化剂上对CHX, CH3OH, HCHO和CO具高度反应活性的表面氧物种O22- (a)和O-(a)的相对含量明显增加密切相关.
The perovskite-type La0.6Sr0.4MnO3 oxide was prepared by citric acid sol-gel method and Ag was modified by Ag to obtain Ag / La0.6Sr0.4MnO3 catalyst.The activity evaluation results showed that the modification of Ag could be significantly increased The catalytic activity of La0.6Sr0.4MnO3 for the complete oxidation of low concentration CH3OH and CO, corresponding to 95% CH3OH and the reaction temperature T95 for the conversion of CO, can be as low as 421 and 370 K. The XPS and LRS spectral characteristics of the catalyst The results revealed that the percentage of moles (mol%) of the highly reactive surface oxygen species O22- (a) and O- (a) in the total surface oxygen on 6% Ag / La0.6Sr0.4MnO3 Nearly twice as much as that of La0.6Sr0.4MnO3 without Ag modification.The results of O2-TPD test showed that the modification, doping and partial substitution of Ag on La0.6Sr0.4MnO3 matrix greatly enhance the low-temperature adsorption capacity of O2 To induce a class of adsorbed oxygen species with a considerable amount of low temperature adsorption-desorption performance.The results show that the catalytic activity of Ag / La0.6Sr0.4MnO3 catalyst for the complete oxidation of CH3OH and CO and the modification of Ag improve the catalytic performance Oxygen adsorption activation ability of low temperature, and the catalyst on the CHX, CH3OH, HCHO and CO The significant increase in the relative content of the highly reactive surface oxygen species O22- (a) and O- (a) is closely related.