Quantitative Determination of H2Se at Model Metal fcc(111) Selenide Surface: DEMS, STM, and AFM Studies
Quantitative Determination of H2Se at Model Metal fcc(111) Selenide Surface: DEMS, STM, and AFM Studies
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模型金属 fcc(111) 硒化物表面 H2Se 的定量测定：DEMS、STM 和 AFM 研究
DOI：
10.1021/acs.jpcc.5b06635
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发表时间：
2015
影响因子：
3.7
通讯作者：
Helmut Baltruschat
中科院分区：
文献类型：
--
作者：
Shahid Iqbal;Christoph Bondü;Helmut Baltruschat
在循环伏安法中，硒在Rh（111）、Pt（111）和Au（111）表面上的电化学沉积仅可能达到约2个单层。在不含Se的溶液中，如通过差示电化学质谱法所证明的，这种硒可以在氢化下作为H2Se大部分解吸，但是大约半个单层停留在表面上并且只能氧化解吸。相应地，还观察到高达单层厚度的一半的沉积物不能在低电位下解吸，而只能氧化解吸;这也通过STM可视化。在低电位下形成的H2Se与H2SeO 3反应，从而产生Se颗粒，如AFM所观察到的。当硒覆盖超过Rh（111）上的半个单层时，由于硒和Rh原子之间的位置交换而发生粗糙化转变。硒的亚单层的氧化剥离后，Rh（111）的单一结晶度在很大程度上被保留，而在沉积2个单层后，接着阳极剥离，Rh表面被粗糙化，如通过循环伏安法所判断的。
Electrochemical deposition of selenium on Rh(111), Pt(111), and Au(111) surfaces in cyclic voltammetry is only possible up to about 2 monolayers. In Se-free solutions, this selenium can be largely desorbed under hydrogenation as H2Se as demonstrated by differential electrochemical mass spectrometry, but about half a monolayer stays on the surface and can only be oxidatively desorbed. Correspondingly, it was also observed that deposits of up to half a monolayer thickness cannot be desorbed at low potentials, but only oxidatively; this was also visualized by STM. H2Se formed at low potentials reacts with H2SeO3and thus generates Se particles as observed by AFM. When the selenium coverage exceeds half a monolayer on Rh(111), a roughening transition due to a place exchange between selenium and Rh atoms occurs. After oxidative stripping of submonolayers of selenium, the single crystallinity of Rh(111) is largely preserved, whereas after deposition of 2 monolayers followed by anodic stripping, the Rh surface is roughened as judged by cyclic voltammetry.