arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2303.07433cond-mat.mtrl-sciphysics.chem-ph
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原始低指数TiO2表面上的水解离

Water dissociation on pristine low-index TiO2 surfaces

Zezhu Zeng, Felix Wodaczek, Keyang Liu, Frederick Stein, Jürg Hutter, Ji Chen, Bingqing Cheng

摘要:

原始低折射率TiO $_2$界面上的水吸收和解离过程很重要,但除了研究充分的金红石(101)和金红石(110)之外,人们对其了解甚少。为了理解这些,我们构建了三套机器学习的潜力,同时适用于各种TiO $_2$表面,基于三个密度泛函理论近似。我们计算了七种TiO $_2$表面的水解离自由能,预测了TiO(100)、TiO(110)、TiO(001)和TiO(011)表面有利于水解离,TiO(101)和TiO(100)表面主要是分子吸附,而计算的金红石(110)表面上的解离分数可能取决于假定的密度泛函。此外,使用自动化算法,我们发现,这些表面遵循不同类型的质子转移和水解离的原子机制:一步,两步,或两者兼而有之。因此,我们的发现表明,不同的原始TiO $_2$表面以不同的方式与水反应,并且不能仅用低能的金红石(101)和金红石(110)表面来表示。

英文摘要:

Water absorption and dissociation processes on pristine low-index TiO$_2$ interfaces are important but poorly understood outside the well-studied anatase (101) and rutile (110). To understand these, we construct three sets of machine learning potentials that are simultaneously applicable to various TiO$_2$ surfaces, based on three density-functional-theory approximations. We compute the water dissociation free energies on seven pristine TiO$_2$ surfaces, and predict that anatase (100), anatase (110), rutile (001), and rutile (011) surfaces favor water dissociation, anatase (101) and rutile (100) surfaces have mostly molecular absorption, while the calculated dissociation fraction on rutile (110) surface may depend on the density functional assumed. Moreover, using an automated algorithm, we reveal that these surfaces follow different types of atomistic mechanisms for proton transfer and water dissociation: one-step, two-step, or both. Our finding thus demonstrates that the different pristine TiO$_2$ surfaces react with water in distinct ways, and cannot be represented using just the low-energy anatase (101) and rutile (110) surfaces.

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