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Water-Hydrogen-Polaron Coupling at Anatase TiO2(101) Surfaces: A Hybrid Density Functional Theory Study.
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2020-04-30 , DOI: 10.1021/acs.jpclett.0c00917
Ya-Nan Zhu 1, 2 , Gilberto Teobaldi 3, 4, 5 , Li-Min Liu 2
Affiliation  

Defects and water generally coexist on the surfaces of reducible metal oxides for heterogeneous photocatalysis in aqueous environments, which makes quantification and understanding of their coupling essential for development of practical solutions. Here we explore and quantify the coupling between water (H2O)- and hydrogen (H)-induced electron–polarons on the TiO2 anatase (101) surface by means of first-principles simulations. Without H2O, the hydrogen-induced electron–polaron localizes preferentially around the energetically favored subsurface H site. Its hopping barrier to neighboring sites in the subsurface is about 0.29 eV. Conversely, following H2O adsorption, surface trapping of the electron–polaron becomes energetically favored, and the diffusion barrier from subsurface to surface decreases by 0.15 eV. H2O adsorption is shown to be effective in decreasing the proton diffusion energy barrier within the same layer by reducing the polaron–proton coupling and promoting diffusion toward the subsurface in line with a recent experimental observation on water-dispersed anatase TiO2 nanoparticles.

中文翻译:

锐钛矿型TiO2(101)表面的水-氢-极化子偶联:混合密度泛函理论研究。

缺陷和水通常共存于可还原金属氧化物的表面上,以在水性环境中进行多相光催化,这使得对它们的耦合进行定量和理解对于开发实际解决方案至关重要。在这里,我们通过第一性原理模拟探索和量化TiO 2锐钛矿(101)表面上水(H 2 O)-和氢(H)诱导的电子-极化子之间的耦合。如果没有H 2 O,则氢诱导的电子极化子会优先定位在受能量支持的地下H位置周围。它对地下相邻位置的跳跃势垒约为0.29 eV。相反,跟随H 2在O吸附作用下,电子极化子的表面俘获变得更加有力,并且从次表面到表面的扩散势垒降低了0.15 eV。根据最近对水分散的锐钛矿型TiO 2纳米粒子的实验观察,H 2 O吸附可通过减少极化子-质子耦合并促进向地下扩散来减少同一层中的质子扩散能垒,这一作用是有效的。
更新日期:2020-04-30
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