Initial oxidation of a Rh(110) surface using atomic or molecular oxygen and reduction of the surface oxide by hydrogen
Initial oxidation of a Rh(110) surface using atomic or molecular oxygen and reduction of the surface oxide by hydrogen
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DOI：
10.1021/jp0508002
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发表时间：
2005-07-21
影响因子：
3.3
通讯作者：
Comelli, G
中科院分区：
文献类型：
--
作者：
Dudin, P;Barinov, A;Comelli, G
本文用横向分辨芯能级谱、扫描隧道显微镜和低能电子衍射研究了Rh（110）表面在原子氧或分子氧气氛中生长的氧化物薄膜的形成条件、形貌和反应性。Rh（110）暴露于原子氧导致即使在室温下也能在表面下掺入氧，并且在类似于520 K的温度下容易形成有序的、横向均匀的表面氧化物，其具有准六方结构和接近于RhO 2的化学计量。在中间氧化阶段，表面氧化物与高覆盖吸附相的区域共存。经过一个长的诱导期，还原的Rh氧化物膜与H-2是非常迅速的，独立的共存的吸附相。通过将Rh（110）表面暴露于分子氧来生长氧化物膜需要更高的压力和温度。在氧化过程中的O-2解离步骤的重要作用是反映了在O-2环境中生长的氧化膜的复杂形态，由不同的Rh和氧原子密度的微观补丁。
The formation conditions, morphology, and reactivity of thin oxide films, grown on a Rh(110) surface in the ambient of atomic or molecular oxygen, have been studied by means of laterally resolved core level spectroscopy, scanning tunneling microscopy and low energy electron diffraction. Exposures of Rh(110) to atomic oxygen lead to subsurface incorporation of oxygen even at room temperature and facile formation of an ordered, laterally uniform surface oxide at similar to 520 K, with a quasi-hexagonal structure and stoichiometry close to that of RhO2. In the intermediate oxidation stages, the surface oxide coexists with areas of high coverage adsorption phases. After a long induction period, the reduction of the Rh oxide film with H-2 is very rapid and independent of the coexisting adsorption phases. The growth of the oxide film by exposure of a Rh(110) surface to molecular oxygen requires higher pressures and temperatures. The important role of the O-2 dissociation step in the oxidation process is reflected by the complex morphology of the oxide films grown in O-2 ambient, consisting of microscopic patches of different Rh and oxygen atomic density.