| 吴凯,王德峥,魏绪明,曹玉明,刘宪春,郭燮贤.Cl/Ag(111)体系研究——Ⅲ.Cl吸附对O_2吸附的影响[J].分子催化(中英文),1993,(4): |
| Cl/Ag(111)体系研究——Ⅲ.Cl吸附对O_2吸附的影响 |
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| DOI： |
| 中文关键词: 银单晶,氯吸附,氧吸附,暴露量,氧物种 |
| 英文关键词:Silver single-crystal, Chlorine adsorption, Oxygen adsorption, Exposure, Oxygen species. |
| 基金项目:国家自然科学基金资助课题 |
| 吴凯 王德峥 魏绪明 曹玉明 刘宪春 郭燮贤 |
中国科学院大连化学物理研究所催化基础国家重点实验室 大连116023
(吴凯，王德峥，魏绪明，曹玉明，刘宪春)
，中国科学院大连化学物理研究所催化基础国家重点实验室 大连116023(郭燮贤)
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| 中文摘要: |
| 考察了Ag(111)表面和吸氯的Ag(111)表面上氧的吸附行为.结果表明在Ag(111)及低暴露量氯吸附的Ag(111)上氧吸附时,表面上均存在弱的分子氧和原子氧物种.但在高暴露量氯吸附的Ag(111)表面上氧吸附时则选择性地只产生表面分子氧物种,这种选择性只与氯的吸附程度有关,而与氯的存在与否无关.结合以前的实验结果,对氯吸附至(c)阶段时的Ag(111)表面上氧的选择性吸附行为的本质作了详细讨论. |
| 英文摘要: |
| The adsorption of oxygen on Ag (111) and Ag (111) previously exposed to Cl was studied. Oxygen adsorption at 170 K on both Ag(111) and Ag(111) previously exposed to a low exposure of Cl(Ag (111)/C1- {a}) produced two surface oxygen species, namely, weakly adsorbed molecular oxygen (vo-o, 600-620 cm-1) and atomic oxygen(vAg-o, 340-380 cm-1). Oxygen adsorption on the surfaces of Ag(111) and Ag(111)/Cl-{a} at room temperature produced primarily atomic oxygen with a slight amount of molecular oxygen species adsorbed on the residual defect sites. The desorption temperature of atomic oxygen was about 520 K. However, oxygen adsorption on Ag(111) previously exposed to a high exposure of Cl (Ag (111 )/Cl- {c}) predominantly produced a molecular oxygne species which was stable to room temperature and desorbed at 380 K. The same altered behavior of oxygen adsorption was also seen on a surface which had undergone a treatment of Cl adsorption to stage (c) and later desorption of Cl at 673 K, but without any annealing of the surface. It is clearly shown that the presence of Cl is not necessary for the altered oxygen adsorption behavior. It appears that the action of Cl is via structural changes rather than an electronic ligand effect, although the presence of Cl does inhibit the total amount of oxygen adsorption to a certain extent. It is the defects produced by Cl adsorption that change the behavior of oxygen adsorption on Ag (111). The surface defects can accelerate the adsorption rate of oxygen and produce selectively surface molecular oxygen species. The defects can also promote surface atomic oxygen to diffuse into the bulk to become subsurface oxygen. |
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