|Title||Structures of defects on anatase TiO2(001) surfaces|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Shi, YL, Sun, HJ, Nguyen, MC, Wang, CZ, Ho, KM, Saidi, WA, Zhao, J|
|Type of Article||Article|
|Keywords||001 facets, chemistry, effective potentials, initio molecular-dynamics, Materials Science, metals, methanol, o-2 adsorption, oxidation, physics, Technology - Other Topics, tio2 photocatalysis, tio2(110)|
Defects on oxide surfaces play a crucial role in surface reactivity and thus it is crucial to understand their atomic and electronic structures. The defects on anatase TiO2(001)-(1 x 4) surfaces are found to be highly reactive; however, due to the surface reconstruction, the defects exhibit a complicated character in different experiments that make it very challenging to determine their atomic structures. Here we present a systematic first-principles investigation of the defects on anatase TiO2(001)-(1 x 4) surfaces based on a global-search adaptive genetic algorithm (AGA) and density functional theory (DFT). For different Ti-O ratios, we identify the low energy defect structures, investigate their electronic structure using a hybrid functional, and map their regions of stability under realistic conditions. We successfully find novel oxygen vacancy (O-V) and Ti interstitial (Ti-ini) structures that are different from the conventional ones in terms of their charge localization, magnetic state, and their scanning-tunneling-microscopy bright-dark image signature. This provides an insight into the complex geometric and electronic structure of the surface defects, and resolves several experimental discrepancies.
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