Nature of visible-light responsive fluorinated titanium dioxides

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 1; no. 41; pp. 12948 - 12953
• Main Authors: Wang, Yun, Zhang, Haimin, Liu, Porun, Sun, Tao, Li, Yibing, Yang, Huagui, Yao, Xiangdong, Zhao, Huijun
• Format: Journal Article
• Language: English
• Published: 01.10.2013
• Subjects: Density functional theory; Fluorination; Nuclear power generation; Origins; Photocatalysis; Surface chemistry; Sustainability; Titanium dioxide
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c3ta12506h

The origin of the visible-light activity of fluorinated TiO sub(2) has been systematically investigated viacomprehensive theoretical studies. The 3-coordinated surface F atoms with higher 1s binding energy are identified to be the origin of the visible light activity of the fluorinated TiO sub(2) by systematically analysing 1s core-level shifts of various types of F atoms in fluorinated TiO sub(2). Further analysing the electronic structures of the fluorinated TiO sub(2) using semi-local density functional theory and non-local hybrid density functional theory calculations demonstrates that the introduction of the 3-coordinated surface F atoms leads to the formation of Ti super(3+) ions in the sub-surface, which is the cause for the bandgap shrinking, increasing the visible-light activity. The results also reveal that the presence of 3-coordinated surface F atoms strengthens the adsorption of hydroxyl groups in their vicinity to enhance the photocatalytic activity. The findings of this work address a long-standing scientific question, providing useful guidance for the design and development of high performance VL photocatalysts.