Catalyst-free activation of peroxides under visible LED light irradiation through photoexcitation pathway

Yaowen Gao; Yixi Li; Linyu Yao; Simiao Li; Jin Liu; Hui Zhang

doi:10.1016/j.jhazmat.2017.01.046

Catalyst-free activation of peroxides under visible LED light irradiation through photoexcitation pathway

J Hazard Mater. 2017 May 5:329:272-279. doi: 10.1016/j.jhazmat.2017.01.046. Epub 2017 Jan 25.

Authors

Yaowen Gao¹, Yixi Li², Linyu Yao², Simiao Li², Jin Liu², Hui Zhang³

Affiliations

¹ Department of Environmental Engineering, Wuhan University, Wuhan, 430079, China; Shenzhen Research Institute of Wuhan University, Shenzhen, 518057, China.
² Department of Environmental Engineering, Wuhan University, Wuhan, 430079, China.
³ Department of Environmental Engineering, Wuhan University, Wuhan, 430079, China; Shenzhen Research Institute of Wuhan University, Shenzhen, 518057, China. Electronic address: eeng@whu.edu.cn.

PMID: 28183016
DOI: 10.1016/j.jhazmat.2017.01.046

Abstract

Catalysts are known to activate peroxides to generate active radicals (i.e., hydroxyl radical (OH) and sulfate radical (SO₄^-)) under certain conditions, but the activation of peroxides in the absence of catalysts under visible light irradiation has been rarely reported. This work demonstrates a catalyst-free activation of peroxides for the generation of OH and/or SO₄^- through photoexcited electron transfer from organic dyes to peroxides under visible LED light irradiation, where Rhodamine B (RhB) and Eosin Y (EY) were selected as model dyes. The formation of OH and/or SO₄^- in the reactions and the electron transfer from the excited dyes to peroxides were validated via electron paramagnetic resonance (EPR), photoluminescence (PL) spectra and cyclic voltammetry (CV). The performance of the peroxide/dye/Vis process was demonstrated to be altered depending on the target substrate. Meanwhile, the peroxide/dye/Vis process was effective for simultaneous decolorization of dyes and production of active radicals under neutral even or basic conditions. The findings of this study clarified a novel photoexcitation pathway for catalyst-free activation of peroxides under visible light irradiation, which could avoid the secondary metal ion (dissolved or leached) pollution from the metal-based catalysts and expand the application range of the peroxide-based catalytic process.

Keywords: Active radicals; Dyes; Electron transfer; Peroxides; Photoexcitation.