Electro-driven cycling Fenton catalysis through two-dimensional electroresponsive metal–organic frameworks for water purification

Abstract

The electro-Fenton process is a promising technology for eliminating emerging organic pollutants from water. However, its potential is hindered by the lack of cathode materials with the essential cycling catalytic functionality for sustained Fenton reactions. In this study, we developed an innovative catalytic cathode comprising a two-dimensional electroresponsive ferrocene metal–organic framework (ER-Fc-MOF) for effective H2O2 activation in a reagent-free dual-cathode electro-Fenton process. The ER-Fc-MOF cathode also enables the electro-driven regeneration of the Fe(II) sites through direct electron transfer within the ferrocene sandwich structure, achieving continuous cycling of the Fc+-Fe(III)/Fc-Fe(II) species for Fenton reactions. Electron paramagnetic resonance and quenching tests confirmed that the ER-Fc-MOF catalytic cathode generates both radical (HO·) and non-radical (1O2) species for highly efficient degradation of organic pollutants across a broad pH range in diverse water matrices. This novel electroresponsive cycling catalyst for the electro-Fenton process presents a promising route towards the development of green and sustainable oxidation technologies for water purification and wastewater treatment. Electro-Fenton treatment holds great promise as an advanced oxidation process for removing emerging organic pollutants, but achieving sustained Fenton reactions remains a challenge. An electroresponsive ferrocene metal–organic framework cathode now enables continuous cycling of the catalytic species for Fenton reactions and achieves efficient water purification.