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Theoretical Insight into the Role of Defects and Facets in the Selectivity of Products in Water Oxidation over Bismuth Vanadate (BiVO4)
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2020-01-21 , DOI: 10.1021/acssuschemeng.9b06404
Taifeng Liu 1 , Ruyue Liu 1 , Qiuye Li 1 , Jianjun Yang 1
Affiliation  

Bismuth vanadate (BiVO4) is an efficient photocatalyst or photoanode in water oxidation. However, the product selectivity in water oxidation over the most exposed clean and defective (001) and (101) facets is not clear. In this work, we investigated the water oxidation reaction on clean and oxygen deficient (001) and (101) facets and on Mo/W-doped facets using density functional theory. The pure (001) facet, we found, promotes OH radical formation. In the presence of oxygen vacancies, the O2 evolution is preferred on the (101) facet with an overpotential of 0.52 V. On doping with Mo/W, the H2O2 evolution is preferred on the (101) facet with the overpotential of about 0.40 V; while on the (001) facet, the O2 evolution is preferred with the overpotential of about 0.5 V. We also found that, on the (101) facet, there is a strong charge transfer from Bi atoms to the intermediates of water oxidation; but on the (001) facet, there is not. Our calculations could guide the design of the photocatalyst toward specific products of the water oxidation reaction, such as an OH radical, H2O2, or O2. Moreover, the results show that the preferred sorption on the (101) facet may be a reason for the photoinduced charge separation between (101) and (001) facets of BiVO4.

中文翻译:

理论上的缺陷和方面在钒酸铋(BiVO 4)的水氧化产物选择性中的作用

钒酸铋(BiVO 4)是水氧化中的有效光催化剂或光阳极。但是,在暴露最干净和有缺陷的(001)和(101)面上,水氧化产物的选择性尚不清楚。在这项工作中,我们使用密度泛函理论研究了清洁和缺氧的(001)和(101)刻面以及Mo / W掺杂的刻面上的水氧化反应。我们发现,纯的(001)刻面可促进OH自由基的形成。在存在氧空位的情况下,在(101)面上的过电势优选为0.52 V的O 2析出。在掺杂Mo / W时,在(101)面上的过电势的H 2 O 2析出是优选的约为0.40 V; 而在(001)面上,O 2最好使用约0.5 V的过电势进行演化。我们还发现,在(101)面上,有很强的电荷从Bi原子转移到水氧化的中间体;但是(001)面上没有。我们的计算可以将光催化剂的设计引向水氧化反应的特定产物,例如OH自由基,H 2 O 2或O 2。而且,结果表明,在(101)小面上的优选吸附可能是BiVO 4在(101)和(001)小面上之间光诱导的电荷分离的原因。
更新日期:2020-01-22
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