Günther Sebastian, Esch Friedrich, del Turco Marco, Africh Cristina, Comelli Govanni, Kiskinova Maya
Department Chemie, Ludwig-Maximilians Universtät München, Butenandtstrasse 11 Haus E, 81377 München, Germany.
J Phys Chem B. 2005 Jun 23;109(24):11980-5. doi: 10.1021/jp050988p.
Using scanning tunneling microscopy, low-energy electron diffraction, and X-ray photoelectron spectroscopy, we studied the evolution of the structure and chemical state of a Rh(110) surface, modified by K adlayers and exposed to high O2 doses at elevated temperatures. We find that oxygen coadsorption on the K-covered Rh(110) leads to massive reconstruction of the Rh(110) surface. Stable reconstructed (10 x 2) and (8 x 2) segmented phases with a local coverage of more than two oxygen atoms per surface Rh atom were observed. Formation of surface oxide, which coexists with the (10 x 2) and (8 x 2) segmented adsorption phases, is evidenced at the highest O2 doses. The development of strongly reconstructed adsorption phases with oxide-like stoichiometry and surface oxide under UHV conditions is explained in terms of the stabilization of the (1 x 2) reconstruction and promotion of O2 dissociation by the K adatoms.
我们使用扫描隧道显微镜、低能电子衍射和X射线光电子能谱，研究了由钾吸附层修饰并在高温下暴露于高剂量氧气的Rh(110)表面的结构和化学状态的演变。我们发现，在覆盖钾的Rh(110)表面上共吸附氧气会导致Rh(110)表面发生大规模重构。观察到稳定的重构(10×2)和(8×2)分段相，每个表面Rh原子的局部覆盖率超过两个氧原子。在最高氧气剂量下，有证据表明形成了与(10×2)和(8×2)分段吸附相共存的表面氧化物。在超高真空条件下，具有类似氧化物化学计量比的强重构吸附相和表面氧化物的形成，是根据(1×2)重构的稳定性以及钾吸附原子对氧气解离的促进作用来解释的。
