International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
Surface Characterization Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
Angew Chem Int Ed Engl. 2017 Apr 3;56(15):4174-4177. doi: 10.1002/anie.201612281. Epub 2017 Mar 15.
O adsorption on Pt surfaces is of great technological importance owing to its relevance to reactions for the purification of car exhaust gas and the oxygen reduction on fuel-cell electrodes. Although the O /Pt(111) system has been investigated intensively, questions still remain concerning the origin of the low O sticking probability and its unusual energy dependence. We herein clarify the alignment dependence of the initial sticking probability (S ) using the single spin-rotational state-selected [(J,M)=(2,2)] O beam. The results indicate that, at low translational energy (E ) conditions, direct activated chemisorption occurs only when the O axis is nearly parallel to the surface. At high energy conditions (E >0.5 eV), however, S for the parallel O decreases with increasing E while that of the perpendicular O increases, accounting for the nearly energy-independent O sticking probability determined previously by a non-state-resolved experiment.
O 在 Pt 表面上的吸附具有重要的技术意义，因为它与汽车尾气净化反应和燃料电池电极上的氧还原有关。尽管 O /Pt(111) 体系已经被广泛研究，但关于低 O 附着概率的起源及其不寻常的能量依赖性问题仍存在疑问。我们在此使用单自旋旋转态选择[(J,M)=(2,2)]O 束澄清了初始附着概率(S)的取向依赖性。结果表明，在低平移能(E)条件下，只有当 O 轴几乎平行于表面时，直接活化化学吸附才会发生。然而，在高能条件下(E>0.5 eV)，平行 O 的 S 随着 E 的增加而减小，而垂直 O 的 S 则随着 E 的增加而增加，这解释了先前通过非态分辨实验确定的几乎与能量无关的 O 附着概率。
