氧化铈对氧化锰表面氧脱附与恢复性能的影响

采用TPD-MS技术研究了Mn-Ce-O体系催化剂的表面氧脱附(供出)和恢复性能,并以甲醇氧化反应为探针考察了催化剂在不同气氛下的氧化活性。结果表明,氧化铈的存在并不影响氧化锰O₂-TPD特征峰的位置,但氧化锰表面的吸附氧数量明显增加,氧化锰表面吸附氧的恢复能力随氧化铈含量的增加而增大。催化剂对甲醇的氧化活性与其表面吸附氧数量有很好的对应关系。催化剂表面氧恢复能力越大,对甲醇的氧化活性受气相氧影响越小。

^^Effect of CeO_2 on Surface Oxygen Desorption and Reproduction of Mn_2O_3

In this paper,the desorption properties of surface oxygen over Mn-Ce-O and its reproduction were investigated by means of TPD-MS. The oxidation activity of methanol on these catalysts was studied under different concentrations of oxygen. There are three peaks in the TPD-MS spectra of Mn-O and Mn-Ce-O catalysts, the first two are attributed to the absorbed oxygen and the last one is ascribed to the lattice.oxygen. CeO2 can not change the position of the O2-TPD feature peaks of Mn2O3, but evidently increases the amount of surface absorbed oxygen.The addition of CeO2 increases the capacity of surface oxygen reproduction of Mn2O3.The oxidation activity of methanol on these catalysts is relative to the absolute amount of surface desorption oxygen of each catalyst.The stronger the reproduction of the surface absorbed oxygen of the catalysts,the less the catalytic oxidation activity is affected by the vapor phase oxygen.