Experimental and theoretical investigation of the enhancement of the photo-oxidation of Hg0 by CeO2-modified morphology-controlled anatase TiO2

Huazhen Shen; Mengjia Lin; Lidong Wang; Zhiwei Huang; Xiaomin Wu; Xiaoqi Jiang; Qing Li; Cheng-Lung Chen; Jingxiang Zhao; Guohua Jing; Chung-Shin Yuan

doi:10.1016/j.jhazmat.2020.124535

Experimental and theoretical investigation of the enhancement of the photo-oxidation of Hg⁰ by CeO₂-modified morphology-controlled anatase TiO₂

J Hazard Mater. 2021 Mar 15:406:124535. doi: 10.1016/j.jhazmat.2020.124535. Epub 2020 Dec 2.

Authors

Affiliations

¹ College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, China.
² North China Electrical Power University, Department Environment Science & Engineering, Hebei Key Lab Power Plant Flue Gas Multipollutant, Baoding, 071003 Hebei, China.
³ Department of Chemistry, National Sun Yat-Sen University, No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan.
⁴ College of Chemistry and Chemical Engineering, and Key Laboratory of Photonic and Electronic Bandgap Materials, Ministry of Education, Harbin Normal University, Harbin 150025, China.
⁵ College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, China. Electronic address: zhoujing@hqu.edu.cn.
⁶ Institute of Environmental Engineering, National Sun Yat-Sen University, No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan. Electronic address: ycsngi@mail.nsysu.edu.tw.

PMID: 33302186
DOI: 10.1016/j.jhazmat.2020.124535

Abstract

This study aims to investigate the coeffects of predominantly exposed anatase TiO₂{001} and {101} and CeO₂ loading on the photo-oxidation of Hg⁰ to relieve the adverse effects caused by higher temperatures of 50-250 °C. The effect of loading CeO₂ on the photocatalytic activity of morphology-controlled TiO₂ was not only investigated using DFT with U correction but also experimentally analyzed by characterizing the electrochemical properties and the formation of free radicals. The theoretical calculation showed that CeO₂ loading on TiO₂{101} was more stable than that on TiO₂{001}. Accordingly, a larger portion of CeO₂ was observed to anchor to the (101) plane than to the (001) plane. CeO₂ loading is more beneficial for increasing the distribution of photo-induced electrons and holes on the surface of 7%CeTi than on the surface of TiO₂ and increases the energy difference between the conduction band edge of 7%CeTi and the standard redox potential of O₂/·O₂^-. Correspondingly, the photocatalytic removal efficiencies (PREs) of Hg⁰ by 7%CeTi were significantly enhanced compared with those of pristine TiO₂. The effect of CeO₂ was highly morphologically dependent on the photocatalytic activity. This study provides valuable insight into surface engineering strategies for morphology-controlled photocatalysts for air pollution control technology.

Keywords: DFT; Free radicals; Hg(0); Morphology control; Photo-oxidation; TiO(2).