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在不同温度的CO2气氛中对Pd膜进行了毒化,将毒化后的Pd膜与氢气反应并测试其氢同位素渗透性能。采用XPS、SEM等检测了CO2在不同温度下对Pd膜毒化后的表面成分与形貌,并对比分析了吸氢前、后的Pd膜表面状态的变化,得出了CO2对Pd膜表面状态的影响规律,探讨了CO2气体的毒化机理。结果表明,CO2分子在Pd表面会解离成为C=O,C-O与O原子,随着温度升高,C=O减少,而C-O与O原子含量增加。当CO2毒化温度达到500℃时,Pd表面会生成PdO并伴有微孔出现,而C-O随温度升高能够稳定吸附于Pd表面。毒化后的试样在常温下进行吸氢反应后表面PdO消失,吸附O含量减少,多孔形貌得到改变。CO2毒化后,由于C-O与O原子在Pd表面吸附并占据了Pd膜表面的氢解离位,从而导致Pd膜透氘能力下降。
The Pd film was poisoned in a CO2 atmosphere at different temperatures, and the poisoned Pd film was reacted with hydrogen to test its hydrogen isotope permeability. The surface composition and morphology of Pd membrane poisoned by CO2 at different temperatures were examined by XPS and SEM. The changes of the surface state of Pd membrane before and after hydrogen absorption were analyzed. The influence of CO2 gas poisoning mechanism was discussed. The results show that CO2 molecules will dissociate into C = O, C-O and O atoms on the surface of Pd. As the temperature increases, C = O decreases and the content of C-O and O atoms increases. When CO2 poisoning temperature reaches 500 ℃, PdO will be formed on the Pd surface accompanied with micropores, while C-O will be stably adsorbed on the Pd surface with increasing temperature. After the poisoned sample was hydrogenated at room temperature, the surface PdO disappeared, the content of adsorbed O decreased, and the porous morphology was changed. After CO2 poisoning, due to the adsorption of C-O and O atoms on the Pd surface and occupying the hydrogen dissociation sites on the surface of the Pd film, the deuterium-removing capability of the Pd film is decreased.