Targeted Coupling of Electrogenerated Reactive Oxygen Species for Deep Pollutant Mineralization

Abstract

Electrochemical oxidation technology holds great promise for wastewater treatment. However, the inherent limitations of single-component reactive oxygen species (ROS) and their low yield impede thorough mineralization of organic pollutants and elevate energy consumption. Herein, we develop a directed ROS coupling oxidation (DRCO) system, which employs a Ni–Sb–SnO2 anode that leverages Ni(III)/Ni(II) redox cycling for highly selective OH generation, coupled with a CrMn@C anode for 1O2 production, significantly enhancing the coexisting ROS yield. By leveraging the electron-withdrawing and donating synergistic effect of •OH and 1O2, the DRCO system removes 61.2–78.5% total organic carbon (TOC) for diverse organics within 20 min. The observed kinetic constants are 1.4–52.6 times higher than those of systems that use •OH or 1O2 alone. Furthermore, the DRCO system achieves 85.4% TOC removal for actual pharmaceutical wastewater and sustains operational stability over a 120 h continuous flow period. Compared to commercial anodes, the DRCO system reduces energy consumption by 72% (to 12.02 kW·h·kgTOC–1) while effectively suppressing the accumulation of toxic intermediate products. This work demonstrates that high-selectivity •OH generation and the elucidated dual-ROS synergistic mechanism jointly offer a viable strategy toward efficient and energy-conscious electrochemical water purification.