Novel Fe7S8/C nanocomposites with accelerating iron cycle for enhanced heterogeneous electro-Fenton degradation of dyes. (20th December 2022)

• Record Type: Journal Article
• Authors: Zhao, Fengyue; Xiao, Juan; Geng, Shipeng; Wang, Yi; Tsiakaras, Panagiotis; Song, Shuqin
• Is Part Of: Electrochimica acta. Volume 436(2022)
• Publication Date: 2022-12-20
• Subjects: Fe7S8/C nanocomposites -- Metal-organic frameworks -- Organic pollutants degradation -- Rhodamine B (RhB) -- Heterogeneous electro-Fenton; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.141381
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Fe7 S8 /C-1-600/GF cathode shows outstanding RhB degradation at wide pH (3.0–11.0). Radicals of ·OH and SO4 · − are responsible for the RhB degradation. Diverse valences of iron and sulfur species facilitates Fe 3+ /Fe 2+ cycling. Both iron cycling acceleration and H2 O2 activation enhance the RhB degradation. Abstract: Fe 3+ /Fe 2+ interconversion is one of the key factors for heterogeneous electro-Fenton degradation of organic pollutants. In this study, MIL-101Fe-derived carbon wrapping Fe7 S8 nanocomposite (Fe7 S8 /C-1-600) exhibits outstanding rhodamine B (RhB) degradation ability with extremely low iron leaching and high recyclable degradability within 60 min in a wide pH range. Moreover, Fe7 S8 /C-1-600 presents a much higher activity for RhB degradation than Fe3 O4 counterpart without sulfidation, which could be mainly attributed to the accelerated Fe 3+ /Fe 2+ cycling by iron with both multiple valences (Fe 0, Fe 2+, and Fe 3+ ) and sulfur species (S 2− and S2 2− ) of the catalyst. The enhancement of H2 O2 adsorption and activation into OH on Fe7 S8 surface is confirmed by density functional theory calculations with respect to that on Fe3 O4 . Interestingly, SO4 · − can be generated by reacting S2 2− with dissolved O2 and subsequently converted into ·OH, which further facilitates RhB degradation. These findings may shed a new insight into the potential application of metal sulfides for wastewater treatment. Graphical abstract: Image, graphical abstract