Highly efficient electro-Fenton process on hollow porous carbon spheres enabled by enhanced H2O2 production and Fe2+ regeneration

• Published in: Journal of hazardous materials 2023-03, Vol.446, p.130664-130664, Article 130664
• Main Authors: Qin, Xin, Wang, Kaixuan, Cao, Peike, Su, Yan, Chen, Shuo, Yu, Hongtao, Quan, Xie
• Format: Article
• Language: English
• Subjects: Electro-Fenton oxidation; Electrogenerated-hydrogen peroxide; Fe3+/Fe2+ cycle; Surface curvature regulation
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130664

Electro-Fenton (e-Fenton) is a promising method for wastewater treatment that relies on powerful ·OH generated via the decomposition of electro-generated H2O2 catalyzed by Fe2+. In this regard, developing a catalyst capable of simultaneously producing H2O2 and accelerating Fe2+ regeneration is of considerable importance; however, this remains a challenge because of the difficulty in modulating the electronic microenvironment. Herein, a hollow porous carbon sphere catalyst (HPCS) is developed to synchronously enhance H2O2 generation and accelerate Fe3+/Fe2+ cycling by constructing an electron-rich microenvironment via surface curvature regulation. The Fe2+ regeneration efficiency reaches 35.5% on HPCS featuring a larger curvature structure (HPCS-TPOS), which is 1.6 times higher than the smaller curvature HPCS-S catalyst (22.8%). Density functional theory reveals that the electron-rich microenvironment on the outer surface of high curvature structure promotes Fe2+ regeneration. The H2O2 production rate on HPCS-TPOS is 47.2 mmol L−1 h−1, exceeding the state-of-the-art e-Fenton catalysts reported. Benefiting from the concurrent high-efficiency of H2O2 production and Fe2+ regeneration, HPCS-TPOS e-Fenton is demonstrated to be efficient for sulfamethoxazole removal with the kinetic rate of 0.30–0.72 min−1 at pH 3–7. This work offers new insight into the design of efficient catalysts by rationally regulating curvature structures for wastewater treatment. [Display omitted] •Enhanced e-Fenton performance on HPCS by rational curvature regulation.•Simultaneously enhanced H2O2 production and accelerated Fe2+ regeneration on HPCS.•High-efficiency and long-term stability of HPCS e-Fenton for pollutant removal.•Capable of actual coking wastewater treatment.