Surface Chemistry of Alanine on Ni{111}
Surface Chemistry of Alanine on Ni{111}
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DOI：
10.1021/acs.jpcc.5b08814
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发表时间：
2015-11
影响因子：
3.7
通讯作者：
R. Nicklin;A. Cornish;A. Shavorskiy;Silvia Baldanza;K. Schulte;Zhi Liu;R. Bennett;G. Held
中科院分区：
文献类型：
--
作者：
R. Nicklin;A. Cornish;A. Shavorskiy;Silvia Baldanza;K. Schulte;Zhi Liu;R. Bennett;G. Held
以L-丙氨酸在Ni{111}上的吸附为对映选择性非均相催化剂模型进行了研究。基于同步加速器的X射线光电子能谱和近边X射线吸收精细结构（NEXAFS）光谱被用来确定的化学状态，键配位，和表面上的分子的面外取向。丙氨酸在250 ~ 320 K之间以阴离子和两性离子形式吸附。NEXAFS光谱表现出与羧酸基团相关的π* 共振的强角度依赖性，这与相对于对应于双齿和三齿结合模式的表面的两个不同取向是相容的。脱附和分解开始在10300 K，与分解发生在一个多步骤的过程高达10450 K。与以前在金属表面上吸附氨基酸的研究相比，这是迄今为止发现的最低分解温度之一，并且低于用于氢化反应的典型温度。
The adsorption of l-alanine on Ni{111} has been studied as a model of enantioselective heterogeneous catalysts. Synchrotron-based X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy were used to determine the chemical state, bond coordination, and out-of-plane orientation of the molecule on the surface. Alanine adsorbs in anionic and zwitterionic forms between 250 and ≈320 K. NEXAFS spectra exhibit a strong angular dependence of the π* resonance associated with the carboxylate group, which is compatible with two distinct orientations with respect to the surface corresponding to the bidentate and tridentate binding modes. Desorption and decomposition begin together at ≈300 K, with decomposition occurring in a multistep process up to ≈450 K. Comparison with previous studies of amino acid adsorption on metal surfaces shows that this is among the lowest decomposition temperatures found so far and lower than typical temperatures used for hydrogenation reactions ...