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首页> 美国卫生研究院文献>Frontiers in Chemistry >First Principles Calculations on the Stoichiometric and Defective (101) Anatase Surface and Upon Hydrogen and H2Pc Adsorption: The Influence of Electronic Exchange and Correlation and of Basis Set Approximations
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First Principles Calculations on the Stoichiometric and Defective (101) Anatase Surface and Upon Hydrogen and H2Pc Adsorption: The Influence of Electronic Exchange and Correlation and of Basis Set Approximations

机译：化学计量和有缺陷的（101）锐钛矿表面以及氢和H2Pc吸附时的第一原理计算：电子交换和相关性以及基组近似的影响

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Anatase TiO2 provides photoactivity with high chemical stability at a reasonable cost. Different methods have been used to enhance its photocatalytic activity by creating band gap states through the introduction of oxygen vacancies, hydrogen impurities, or the adorption of phthalocyanines, which are usually employed as organic dyes in dye-sensitized solar cells. Predicting how these interactions affect the electronic structure of anatase requires an efficient and robust theory. In order to document the efficiency and accuracy of commonly used approaches we have considered two widely used implementations of density functional theory (DFT), namely the all-electron linear combination of atomic orbitals (AE–LCAO) and the pseudo-potential plane waves (PP–PW) approaches, to calculate the properties of the stoichiometric and defective anatase TiO2 (101) surface. Hybrid functionals, and in particular HSE, lead to a computed band gap in agreement with that measured by using UV adsorption spectroscopy. When using PBE+U, the gap is underestimated by 20 % but the computed position of defect induced gap states relative to the conduction band minimum (CBM) are found to be in good agreement with those calculated using hybrid functionals. These results allow us to conclude that hybrid functionals based on the use of AE–LCAO provide an efficient and robust approach for predicting trends in the band gap and the position of gap states in large model systems. We extend this analysis to surface adsorption and use the AE–LCAO approach with the hybrid functional HSED3 to study the adsorption of the phthalocyanine H2Pc on anatase (101). Our results suggest that H2Pc prefers to be adsorbed on the surface Ti5c rows of anatase (101), in agreement with that seen in recent STM experiments on rutile (110).
机译：锐钛矿型TiO2以合理的成本提供具有高化学稳定性的光活性。通过引入氧空位，氢杂质或酞菁的引入来产生带隙状态，已采用了不同的方法来增强其光催化活性，这些方法通常用作染料敏化太阳能电池中的有机染料。预测这些相互作用如何影响锐钛矿的电子结构需要一种有效而稳健的理论。为了证明常用方法的效率和准确性，我们考虑了密度泛函理论（DFT）的两种广泛使用的实现方式，即原子轨道的全电子线性组合（AE-LCAO）和伪势平面波（ PP–PW）方法，以计算化学计量和有缺陷的锐钛矿型TiO2（101）表面的特性。混合功能，尤其是HSE，导致计算出的带隙与使用UV吸收光谱法测得的带隙一致。当使用PBE + U时，间隙被低估了20％，但发现缺陷引起的间隙状态相对于导带最小值（CBM）的计算位置与使用混合功能计算的位置非常一致。这些结果使我们得出结论，基于AE–LCAO的混合功能为大型模型系统中的带隙趋势和带隙状态的位置预测提供了一种有效而强大的方法。我们将此分析扩展到表面吸附，并使用AE–LCAO方法与杂合功能HSED3来研究酞菁H2Pc在锐钛矿上的吸附（101）。我们的结果表明，H2Pc倾向于吸附在锐钛矿（101）的表面Ti5c行上，这与最近在STM上对金红石（110）进行的STM实验一致。

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