### TiO2表面吸附三氟乙酸的密度泛函理论研究

1. a 内蒙古自治区绿色催化重点实验室 化学与环境科学学院 内蒙古师范大学 呼和浩特 010022;
b 理论与计算化学国家重点实验室 吉林大学 长春 130023
• 投稿日期:2012-03-18 发布日期:2012-08-03
• 通讯作者: 刘子忠 E-mail:zizhliu@yahoo.com.cn
• 基金资助:

项目受国家自然科学基金(No. 21063009);内蒙古自然科学基金(2012MS0218)和内蒙古人才基金资助.

### Study on Trifluoroacetic Acid Adsorbed on TiO2 Surface with Density Functional Theory

Cui Wenyinga, Liu Zizhonga, Jiang Yajuna, Wang Naa, Feng Jikangb

1. a Inner Mongolia Key Laboratory of Green Catalysis, College of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot 010022;
b State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, China
• Received:2012-03-18 Published:2012-08-03
• Supported by:

Project supported by the National Natural Science Foundation of China (No. 21063009), the Natural Science Foundation of Inner Mongolia (No. 2012MS0218) and the Talent Development Foundation of Inner Mongolia.

The method and mechanism on the perfluorinated carboxylic acids (PFCAs) degradation is a hot issue. The crystal lattice structures of the anatase TiO2(101), (001), (110), (210), the rutile TiO2(110), (001), (101), (210) and the brookite TiO2 (210), (101), (001), (110) were optimized with the CASTEP program in Materials Studio package based the density functional theory (DFT). It is found that the energies of the anatase (101), rutile (110) and brookite (210) are the lowest, and the most stable adsorption surfaces, respectively. The adsorption energies of the 18 kinds of the optimized modes on the most stable TiO2 surfaces adsorbed by trifluoroacetic acid (TFA) were calculated. It is indicated that the absorption energy of the mode which the TFA is perpendicular to the brookite (210) surface and the carboxyl group of H adsorbed by Ti atom on the brookite (210) is the biggest, and the adsorption structure is the most stable, and the adsorption mode is the best. The partial state densities for the three kinds of the most stable absorption modes were calculated. It is revealed that the covalent interaction of the TFA on bookite (210) surface is weak, resulted from the narrowing of the band gap that the 2p orbital of O, F of TFA inserts into between the valence band (VB) and conduction band for TiO2. In the best adsorption mode, before and after adsorption the band gap goes down from 3.06 eV to 2.80 eV, i.e., photocatalytic wavelength increases from 385 nm to 443 nm, so that the visible light absorption efficiency is increased.