Raman Abhinav S, Selloni Annabella
Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA.
Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
Angew Chem Int Ed Engl. 2025 Aug 11;64(33):e202507721. doi: 10.1002/anie.202507721. Epub 2025 Jun 30.
A molecular-level understanding of the effects of ambient organic compounds on the wettability of titanium dioxide ( ) surfaces is relevant to many of its energy-related and environmental applications. Herein, we focus on two common atmospheric carboxylic acids, formic and acetic acid, and characterize their adsorption/ desorption at the aqueous interfaces of anatase and rutile using molecular dynamics with an ab initio deep neural network potential. Our simulations show that these acids prefer to be localized in the interfacial water layers close to the surface where they are stabilized by the interaction/exchange of their acid proton with a surface oxygen, rather than chemisorb at the surface Ti sites by displacing the adsorbed water. Notably, these acids make the surface of anatase hydrophobic, whereas the larger fraction of adsorbed water dissociation can offset their effect on rutile. These results provide a picture where carboxylic acids control the wettability of largely through acid-base chemistry at the interface rather than chemisorption on the oxide surface, a finding that can help improve the design of self-cleaning surfaces and photocatalytic devices.
从分子层面理解环境有机化合物对二氧化钛（TiO₂）表面润湿性的影响，与其许多能源相关和环境应用密切相关。在此，我们聚焦于两种常见的大气羧酸——甲酸和乙酸，并使用具有从头算深度神经网络势的分子动力学方法，表征它们在锐钛矿型和金红石型TiO₂水界面处的吸附/解吸情况。我们的模拟结果表明，这些酸更倾向于定位在靠近TiO₂表面的界面水层中，在那里它们通过酸质子与表面氧的相互作用/交换而得以稳定，而不是通过取代吸附水在表面Ti位点上进行化学吸附。值得注意的是，这些酸使锐钛矿型表面疏水，而较大比例的吸附水解离可以抵消它们对金红石型的影响。这些结果呈现出一幅图景：羧酸主要通过界面处的酸碱化学作用而非在氧化物表面的化学吸附来控制TiO₂的润湿性，这一发现有助于改进自清洁表面和光催化器件的设计。
