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Controlled Formation of Defective Shell on TiO2 (001) Facets for Enhanced Photocatalytic CO2 Reduction
ChemCatChem ( IF 3.8 ) Pub Date : 2019-04-08 , DOI: 10.1002/cctc.201900061
Rui Shi 1 , Yong Chen 1
Affiliation  

Defective black TiO2 has attracted considerable attention as photocatalyst for highly efficient solar energy conversion. However, it still remains a challenge to understand the basic role of defective shell on the basis of crystal facet engineering, due to the difficulty in generating defects merely on a specific facet. Herein, we develop a novel strategy to precisely control the formation of defective shell only on {001} facets of TiO2 nanocrystals due to the anisotropic effect of the crystal facets, which enables the investigation of defective shell on a specific facet to be achieved. It is found that the defective shell, middle interface layer and crystalline core together constitute a homojunction (TiO2‐homojunction). The defective shell of TiO2‐homojunction realizes the effective spatial separation of photogenerated electrons and holes. Moreover, the presence of Ti3+ ion and oxygen vacancies in defective shell can induce high free electron concentration and serve as active sites to promote the adsorption and activation of CO2 molecules. As a result, the TiO2‐homojunction exhibits significant photocatalytic behavior for CO2 reduction in a gas‐solid system. More interestingly, the position of redox reaction is reversed due to the controlled formation of defective shell, where {001} facets act as reduction sites and {101} facets as oxidation sites during photocatalytic process.

中文翻译:

控制在TiO2(001)面上形成缺陷的壳层以增强光催化还原CO2的能力

有缺陷的黑色TiO 2作为用于高效太阳能转换的光催化剂已引起了广泛的关注。然而,由于难以仅在特定刻面上产生缺陷,因此基于晶体刻面工程来理解缺陷壳的基本作用仍然是一个挑战。在本文中,我们开发了一种新颖的策略来精确控制由于TiO 2纳米晶面的各向异性效应而仅在TiO 2纳米晶体的{001}面上形成缺陷壳的情况,从而能够研究特定面上的缺陷壳。发现有缺陷的壳,中间界面层和结晶核共同构成了同质结(TiO 2-同质结)。TiO的缺陷外壳2同质结实现了光生电子和空穴的有效空间分离。此外,有缺陷的壳中存在Ti 3+离子和氧空位可诱导高自由电子浓度,并充当促进CO 2分子吸附和活化的活性位点。结果,在气固体系中,TiO 2-同质结对CO 2还原表现出显着的光催化性能。更有趣的是,由于有缺陷的壳的受控形成,氧化还原反应的位置相反,其中在光催化过程中,{001}刻面充当还原位点,{101}刻面充当氧化位点。
更新日期:2019-04-08
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