Reconfiguring interfacial hydrogen-bond networks to enhance anodic oxidation for efficient wastewater treatment

Anodic oxidation is a pivotally electrochemical technology for wastewater treatment containing emerging contaminants such as isothiazolinone antimicrobials, but sluggish interfacial water-splitting kinetics for hydroxyl radical (•OH) formation and a limited oxidation range, constrain its industrial scalability. This study leverages Fe³⁺ to strengthen interfacial water hydrogen bond, accelerating •OH formation and high-valent iron production, thus enhancing oxidation kinetics and scope. [Fe(OH)(H₂O)₅]²⁺ enhances the hydrogen-bond (H-bond) population at the electrode surface-particularly 4-HB-H₂O motifs increase from 21% to 37% and weakens O-H bonds, due to its strong hydration and polarization ability. This reconfigured interfacial water H-bond structure markedly enhances water dissociation, leading to a 7-fold increase in the •OH concentration. Ultimately, Fe³⁺-mediated precise tuning of the H-bond network of water molecules enables non-selective degradation of diverse emerging contaminants, delivering stable long-term flow operation of 500 hours with ~95% removal efficiency maintained for contaminant. The system achieves a 44.3% cost reduction relative to conventional boron-doped diamond electrodes, establishing a convenient approach for industrial-scale electrochemical water treatment.