Köppen S, Langel W
Institut für Biochemie, Universität Greifswald, Greifswald, Germany.
Phys Chem Chem Phys. 2008 Apr 14;10(14):1907-15. doi: 10.1039/b719098k. Epub 2008 Feb 28.
The adsorption of several small organic molecules on rutile (110) and (100) as well as on anatase (101) surfaces was investigated by Car-Parrinello molecular dynamics in aqueous solution and a new approach to the calculation of adsorption energies is proposed, taking into account the potential energy fluctuation of larger systems. Acetylene and ethylene insert into twin oxygen vacancies in the surface and form polarized covalent Ti-C bonds. In one case spontaneous coupling of two acetylene molecules to a C(4)H(3) molecule with a structure similar to trans-butadiene was observed. Neutral catechol and the singly charged anion were not reactive on any titanium dioxide surface, but the twofold-charged anion attained stable mono- and bidentated geometries on anatase. Methanol, ethanol, formaldehyde and acetaldehyde adsorbed with their functional groups. Very stable geometries provide a Ti-O bond and have adsorption energies of 60-200 kJ/mol. The adsorbates compete with water molecules for similar adsorption sites in point defects as well as on perfect surfaces.
通过Car-Parrinello分子动力学方法，在水溶液中研究了几种小有机分子在金红石（110）和（100）以及锐钛矿（101）表面上的吸附情况，并提出了一种计算吸附能的新方法，该方法考虑了更大体系的势能波动。乙炔和乙烯插入表面的孪晶氧空位中，并形成极化的共价Ti-C键。在一种情况下，观察到两个乙炔分子自发偶联形成一个结构类似于反式丁二烯的C₄H₃分子。中性儿茶酚和单电荷阴离子在任何二氧化钛表面上都没有反应活性，但双电荷阴离子在锐钛矿上获得了稳定的单齿和双齿几何构型。甲醇、乙醇、甲醛和乙醛通过其官能团进行吸附。非常稳定的几何构型提供了一个Ti-O键，吸附能为60 - 200 kJ/mol。吸附质与水分子在点缺陷以及完美表面上争夺类似的吸附位点。
