Efficient charge separation in sulfur doped AgFeO2 photocatalyst for enhanced photocatalytic U(VI) reduction: The role of doping and mechanism insights

Yadan Guo; Shuaihang Li; Fan Yang; Chenxi Li; Yaoping Guo; Keng Xuan; Guanghui Wang; Yunhai Liu; Jun Li

doi:10.1016/j.jhazmat.2022.129734

Efficient charge separation in sulfur doped AgFeO₂ photocatalyst for enhanced photocatalytic U(VI) reduction: The role of doping and mechanism insights

J Hazard Mater. 2022 Oct 15:440:129734. doi: 10.1016/j.jhazmat.2022.129734. Epub 2022 Aug 8.

Authors

Yadan Guo¹, Shuaihang Li¹, Fan Yang², Chenxi Li², Yaoping Guo², Keng Xuan², Guanghui Wang¹, Yunhai Liu³, Jun Li⁴

Affiliations

¹ State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China; School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang 330013, China.
² School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang 330013, China.
³ State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China. Electronic address: yhliu@ecut.edu.cn.
⁴ Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450052, China. Electronic address: junli2019@zzu.edu.cn.

PMID: 35988487
DOI: 10.1016/j.jhazmat.2022.129734

Abstract

Photocatalytic reduction of U(VI) in aqueous solutions has been considered as an efficient and promising technology to solve radioactive U pollution. In this work, density functional theory (DFT) calculations were firstly employed to optimize and compare the adsorption configurations combined uranium with four given photocatalysts, then their adsorption energies were - 0.97 eV for AgFeO₂, - 1.15 eV for Zn doped AgFeO₂, - 1.73 eV for Cu doped AgFeO₂ and - 2.66 eV for S doped AgFeO₂, respectively, indicating the sulfur doping plays a major role in U(VI) photoreduction. Herein, a visible light responsive efficient sulfur doped AgFeO₂ photocatalyst (S doped AgFeO₂) was synthesized and utilized to photocatalytic reduction of U(VI) in aqueous solutions. According to XRD, XPS and TEM analysis, the sulfur was successfully doped in AgFeO₂ via the hydrothermal method. The batch experimental showed that S doping enhanced the U(VI) photoreduction activity of AgFeO₂, and the S-AFO-3 photocatalyst exhibited the highest photocatalytic activity (92.57%), which was 1.5 times than that of pure AgFeO₂. ESR, PL and DFT results demonstrated that the enhancement of adsorbed U(VI) photoreduction was attributed to the own unique effect of oxygen vacancy defects and efficient charge separation of S doped AgFeO₂ photocatalyst. Due to its higher adsorption energies, fast-U(VI) photoreduction rate and superior chemical stability, the sulfur doped AgFeO₂ photocatalyst is hoped for water remediation containing U(VI) wastewater.

Keywords: AgFeO(2); DFT calculation; Oxygen vacancies; S doping; U(VI) photoreduction.