XPS and TPD study of NO interaction with Cu(111): Role of different oxygen species

The adsorption and reaction of NO on clean and O-precovered Cu(111) has been studied using X-ray photoelectron spectroscopy and temperature-programmed desorption spectroscopy. By varying NO exposure and annealing temperature, two different types of chemisorbed oxygen species, with O 1s binding energies (BE) of 531.0 (O531) and 529.7 eV (O529), were prepared on Cu(111). In the presence of O531 species, the relative occupation of different NO adsorption states was largely affected, and most of the adsorbed NO(a) underwent dissociative desorption, releasing N2O and N2 upon heating. In contrast, in the presence of O529 species, the dissociative desorption of NO(a) was largely suppressed. Furthermore, the O529 species show a more significant blocking effect on NO adsorption than the chemisorbed O531 species. Our results reveal that the effect of precovered oxygen species on the adsorption and reaction of NO on Cu(111) is closely related to the type of oxygen species and oxygen coverage.

摘要利用X射线光电子能谱和程序升温脱附谱研究了NO在清洁和预吸附氧的Cu(111)表面上的吸附和反应. 通过改变NO的暴露量和退火温度, 在Cu(111)表面可以制备出不同种类的化学吸附氧物种, 其O 1s的结合能分别位于531.0 eV (O531)和529.7 eV (O529). 表面O531物种的存在对NO的不同吸附状态有着显著影响, 同时使得大部分NO吸附分子(NO(a))在加热过程中发生分解并以N2O和N2形式脱附; 而表面O529物种对NO(a)的解离脱附有着明显的抑制作用. 相对于O531物种来说, O529物种对NO吸附表现出更强的位阻效应. 上述结果表明, NO在Cu(111) 表面的吸附和分解行为与预吸附氧物种的种类和覆盖度密切相关.

Graphical AbstractThe adsorption and reaction behavior of NO on Cu(111) largely depends on the type of precovered oxygen species, which were prepared by varying NO exposure and annealing temperature.Figure optionsDownload as PowerPoint slide