A Dual‐Cathode System with a Naturally Aspirated Cathode and a Bimetallic Quasi‐MOF Derived Electrode for Efficient Heterogeneous Fenton over a Wide pH Range

Abstract The heterogeneous electro‐Fenton (HEF) process exhibits substantial potential for environmental remediation but suffers from slow Fe(II) regeneration kinetics, catalyst instability, and poor recovery efficiency. Herein, a novel dual‐cathode system is introduced based on electrocatalytic membranes, consisting of a naturally aspirated cathode (NAC) and a bimetallic quasi‐MOF derived electrode (MNAC@Cu‐MIL‐88B(Fe)), decoupling hydrogen peroxide (H ₂ O ₂ ) generation and activation. Compared to traditional HEF, H ₂ O ₂ is spontaneously produced on NAC via oxygen reduction reaction (ORR), eliminating aeration energy consumption. MNAC@Cu‐MIL‐88B(Fe) is synthesized through in situ growth on modified NAC (MNAC) and controlled thermal conversion, with copper (Cu) acting as an electron shuttle mediator, accelerating Fe(III)/Fe(II) cycling. Consequently, the system achieves 99.4% removal of 2,4‐dichlorophenoxyacetic acid (2,4‐D) in 90 min with minimal energy consumption (0.09 kWh(g TOC) ⁻¹ ). Endowed with stable PTFE membranes as the substrate, the dual‐cathodes enable facile recycling and maintenance. Mechanism studies reveal that the doped‐Cu shifts the d‐band center of MNAC@Cu‐MIL‐88B(Fe) closer to the Fermi energy level, enhancing d‐electron hybridization with H ₂ O ₂ and •OH generation. Furthermore, the Cu‐mediated electron shuttle process achieves a 93% Fe(II) regeneration rate through bimetallic synergy, ultimately improving HEF efficiency. This work offers a viable strategy for designing multimetallic quasi‐MOF derivatives and dual‐cathode systems, enhancing the potential for environmental remediation.