Co(0001)表面氧物种及其与CO的作用

Surface Oxygen Species and the Interaction with CO on Co(0001)

通过高分辨电子能量损失谱(HREELS)、俄歇电子能谱(AES)、低能电子衍射(LEED)等表征手段,考察室温条件下Co(0001)表面O_2的吸附、活化及其与CO的相互作用.室温下少量O_2的吸附出现位于69.9meV的能量损失峰,可归属为表面化学吸附氧物种,随着O_2暴露量的增加,出现位于56.6meV的能量损失峰对应于近表面区域氧物种.通过升温闪退及与CO相互作用的考察,表明近表面区域氧物种较不稳定.室温下,表面吸附的CO可以被表面吸附氧氧化,而表面氧物种则需要在较高温度下才能被CO还原除去.

The adsorption,activation of O2 molecule, as well as, the interaction with CO on the Co（0001） surface have been investi- gated with high-resolution electron energy loss spectroscopy （HREELS）, low-electron energy diffraction （LEED）, and Auger electron energy spectroscopy （AES）.The results show that chemisorbed oxygen species and CoO are stable at room temperature （RT） ,with an energy peak loss at 69.9 meV.At higher O2 exposure,another energy peak loss at 56.6 meV emerges, which can be ascribed to subsurface oxygen species.The results turn out to be that this oxygen species is less stable towards annealing in vacuum and interacting with CO.The CO on surface could be replaced by oxygen at RT,on the contrary,the surface oxygen species removed by CO requires a higher temperature.