X射线光电子能谱
吸附
镝
氮化物
俄歇电子能谱
化学
氮气
分析化学(期刊)
氨
微晶
螺旋钻
无机化学
结晶学
物理化学
原子物理学
核磁共振
图层(电子)
有机化学
核物理学
物理
作者
John A. Schreifels,J.E. Deffeyes,Laurence D. Neff,John White
标识
DOI:10.1016/0368-2048(82)85017-2
摘要
The adsorption of N2, NH3, NO, and N2O onto clean polycrystalline dysprosium at 300 and 115 K and the changes undergone by the adsorbed species upon heating from 115 K have been investigated using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). At 115 K, N2 adsorbs dissociatively, vielding two peaks in the N 1s region at 396.2 and 398.2 eV corresponding respectively to a nitride and to chemisorbed nitrogen N(a). No peaks corresponding to molecularly adsorbed N2 (BE 400.2 eV [10]) were observed. Upon heating the sample the N(a) is converted into the nitride species, as evidenced by a decrease in the 398.2 eV peak and a corresponding increase in the 396.2 eV peak. At a warm-up temperature of 300 K, the N(a) species accounts for only ∼10% of the total nitrogen on the surface. Ammonia adsorbed at 115 K shows three distinct peaks, at 401.7, 399.3 and 396.2 eV, corresponding to molecular, partly dissociated, and completely dissociated (nitride) ammonia. Upon heating multilayer ammonia to 175 K, it desorbs to leave predominantly the peak corresponding to the partly dissociated species. Upon further heating the molecular and partly dissociated ammonia is converted into the nitride species. At 400 K only nitride-type nitrogen remains on the surface. The adsorption of NO and N2O at 115 K is predominantly dissociative. NO has N 1s peaks at 403.1 and 396.3 eV corresponding possibly to molecularly adsorbed NO, and to nitride species. After N2O adsorption there is very little nitrogen on the surface. Adsorption of N2 and NO at 300 K yields only the peak at 396.2 eV, whereas NH3 yields, in addition to this peak, a small intensity (∼20%) of the peak at 398.2 eV (partly dissociated ammonia).
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