Zou Yu, Yang Kaimeng, Chen Qirong, Wang Haitao, Meng Xiangfu
Department of Chemistry, Capital Normal University Beijing 100048 China
Beijing Center for Physical and Chemical Analysis (BCPCA) Beijing 100089 China
RSC Adv. 2018 Oct 31;8(64):36819-36825. doi: 10.1039/c8ra07543c. eCollection 2018 Oct 26.
The construction of defects on TiO surface has attracted great interest due to their prominent effect on photocatalytic activity. However, most synthesis methods often lead to unstable oxygen vacancies which limits their effect for improvement of visible light photoactivity. In this work, stable oxygen vacancies were successfully introduced in commercial TiO (P25) one-step molten salt (MS) method. Due to the incomplete combination of trifluoroacetic acid (TFA) adsorbed on TiO in MS, the lattice oxygen atoms of TiO were consumed resulting in the formation of oxygen vacancies both on the surface and in the bulk of TiO. The optical adsorption edge of oxygen defective TiO showed a substantial shift toward to visible light region combining with a color variation from white to dark blue. Meanwhile, the morphology and crystalline phase were also changed because of the presence of oxygen vacancies. As a result, the blue TiO with rich oxygen vacancies exhibited a considerably enhanced photocatalytic activity for decomposition of rhodamine B (RhB) and selective oxidation of benzyl alcohol under visible light irradiation.
TiO表面缺陷的构建因其对光催化活性的显著影响而备受关注。然而，大多数合成方法往往会导致不稳定的氧空位，这限制了它们对可见光光活性改善的作用。在这项工作中，通过一步熔盐（MS）法成功地在商用TiO（P25）中引入了稳定的氧空位。由于在熔盐中吸附在TiO上的三氟乙酸（TFA）不完全结合，TiO的晶格氧原子被消耗，导致在TiO的表面和体相中都形成了氧空位。氧缺陷TiO的光吸收边缘向可见光区域有明显的偏移，并伴随着颜色从白色变为深蓝色。同时，由于氧空位的存在，其形貌和晶相也发生了变化。结果，具有丰富氧空位的蓝色TiO在可见光照射下对罗丹明B（RhB）的分解和苯甲醇的选择性氧化表现出显著增强的光催化活性。
