Adsorption of C2H4 on Stepped Cu(410) Surface: A Combined TPD, FTIR, and DFT Study
Adsorption of C2H4 on Stepped Cu(410) Surface: A Combined TPD, FTIR, and DFT Study
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DOI：
10.1021/jp509228v
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发表时间：
2014-11-27
影响因子：
3.7
通讯作者：
Kokalj, Anton
中科院分区：
文献类型：
--
作者：
Makino, Takamasa;Okada, Michio;Kokalj, Anton
采用红外反射吸收光谱、程序升温脱附和密度泛函理论计算研究了乙烯（C2H4）在阶梯状Cu（410）表面上的吸附。在 93 K 时，乙烯以分子方式吸附在 Cu(410) 上并形成三种不同的 p 键物种，所有这些物种均在 230 K 以下解吸。尽管这一发现直接表明这三种物种对应于吸附在阶梯边缘和两个不同阶梯原子处的乙烯，但更详细的分析表明情况并非如此。相反，这三个物种的起源源于（i）乙烯在阶梯边缘吸附的强烈偏好，（ii）相邻阶梯边缘位点吸附的乙烯之间显着的分子间排斥力，以及（iii）阶梯位点上的随机吸附之间的相互作用。最近的实验研究表明，由于开放的阶梯边缘，乙烯在 Cu(410) 上脱氢（Kravchuk 等人 J. Phys. Chem. C 2009, 113, 20881）。目前的数据证实了脱氢的发生，但没有形成双键乙烯。
Adsorption of ethylene (C2H4) on stepped Cu(410) surface was investigated with infrared reflectionabsorption spectroscopy, temperature-programmed desorption, and density functional theory calculations. At 93 K, ethylene adsorbs molecularly on Cu(410) and forms three different p-bonded species, all of which desorb below 230 K. Even though this finding straightforwardly suggests that the three species correspond to ethylene adsorbed at the step-edge and at the two different terrace atoms, a more detailed analysis reveals this is not the case. Instead, the origin of the three species stems from the interplay between (i) strong preference of ethylene to adsorb at the step-edge, (ii) significant intermolecular repulsion between the ethylene adsorbed at the adjacent step-edge sites, and (iii) the random adsorption on the terrace sites. Recent experimental studies have suggested that ethylene is dehydrogenated on Cu(410) due to the open step-edges (Kravchuk et al. J. Phys. Chem. C 2009, 113, 20881). The present data confirm the occurrence of dehydrogenation but not the formation of a di-s-bonded ethylene.