Surface Chemistry of Alanine on Ni{111}
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- 作者：Richard E. J. Nicklin ; Alix Cornish ; Andrey Shavorskiy ; Silvia Baldanza ; Karina Schulte ; Zhi Liu ; Roger A. Bennett ; Georg Held
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：November 25, 2015
- 年：2015
- 卷：119
- 期：47
- 页码：26566-26574
- 全文大小：638K
- ISSN：1932-7455
文摘
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 鈮?20 K. NEXAFS spectra exhibit a strong angular dependence of the 蟺* 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 鈮?00 K, with decomposition occurring in a multistep process up to 鈮?50 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 where modified Ni catalysts are used.