Grote Fredrik, Lyubartsev Alexander
Deparment of Chemistry, Stockholm University, Svante Arrhenius väg 16 C, 10691 Stockholm, Sweden.
Nanomaterials (Basel). 2025 Feb 27;15(5):364. doi: 10.3390/nano15050364.
Hydrated anatase (101) titanium dioxide surfaces with oxygen vacancies have been studied using a combination of classical and ab initio molecular dynamics simulations. The reactivity of surface oxygen vacancies was investigated using ab initio calculations, showing that water molecules quickly adsorb to oxygen vacancy sites upon hydration. The oxygen vacancy then quickly reacts with the adsorbed water, forming a protonated bridging oxygen atom at the vacancy site and at a neighboring oxygen bridge. Ab initio simulations also revealed that this occurs via a short-lived hydronium ion intermediate. It was investigated how this reaction affects the structure and dynamics of water near the anatase surface. Classical molecular dynamics simulations of surfaces with and without oxygen vacancies showed that vacancies disrupt the second solvation shell, consisting of water molecules hydrogen bonded to the surface, thereby changing the local water density and diffusion as well as the binding modes for hydrogen bonding. Our findings support the hydroxylation of oxygen vacancies on anatase (101) surfaces, rather than stabilization by molecular adsorption or subsurface diffusion. The work gives new atomistic insight into water structure and surface chemistry on the catalytically relevant anatase (101) titanium dioxide surface.
采用经典分子动力学模拟和从头算分子动力学模拟相结合的方法，对具有氧空位的水合锐钛矿（101）二氧化钛表面进行了研究。利用从头算计算研究了表面氧空位的反应活性，结果表明，水合后水分子会迅速吸附到氧空位处。然后，氧空位迅速与吸附的水发生反应，在空位处和相邻的氧桥上形成一个质子化的桥连氧原子。从头算模拟还表明，这一过程是通过一个短寿命的水合氢离子中间体发生的。研究了该反应如何影响锐钛矿表面附近水的结构和动力学。对有氧空位和无氧空位的表面进行经典分子动力学模拟，结果表明，空位会破坏由与表面形成氢键的水分子组成的第二溶剂化层，从而改变局部水密度、扩散以及氢键的结合模式。我们的研究结果支持锐钛矿（101）表面氧空位的羟基化，而不是通过分子吸附或次表面扩散实现稳定化。这项工作为催化相关的锐钛矿（101）二氧化钛表面的水结构和表面化学提供了新的原子层面的见解。
