摘要
用TPR法研究了Cu-O/γ-Al_2O_3(Ⅰ)和Ce-O/γ-Al_2O_3(Ⅱ)体系中的氧和氢反应。结果表明可以区别试样中的表层氧和体相氧。(Ⅰ)的TPR峰温在240～320℃,(Ⅱ)的TPR峰温>450℃。在Cu-Ce-O/γ-Al_2O_3(Ⅲ)的TPR谱上,(Ⅱ)的特征峰消失,而(Ⅰ)的三个特征峰有融合的趋势,表明铈的加入提高了晶格氧的迁移速度。当CuO/CeO_2的重量比为1时,(Ⅱ)可在更低的温度下被氢还原。用氢氧滴定技术考察了(Ⅰ)～(Ⅲ),证明在CU-O加入Ce可明显地提高试样的贮氧能力和还原态样品的再氧化速度。
The reaction between H2 and oxygen of Cu-O/γ-Al2O3 (I), Ce-O/ γ-Al2O3(Ⅱ) was studied by TPR method. The results indicate that the surface capping oxygen and the bulk oxygen anions can be distinguished. The TPR spectra of (I) show the peaks at 240-320℃ and that of (Ⅱ) show the peaks at >450℃. In the TPR spectra of Cu-Ce-O/γ-Al2O3(Ⅲ), the feature peaks of(Ⅱ) are not seen and there is tendency of mixing the three feature peaks of (I) together, which shows that the removal of the lattice oxygen can be accelerated by the addition of CeO2 to (I). As the weight ratio of CuO to CeO2 is 1, (Ⅲ) is reduced by H2 more easily. The H2-O2 titration shows that the addition of Ce to CuO can enhance the oxygen storage capacities obviously and raise the re-oxidation speed of the reduced state catalysts.
