Surface amorphization enables robust catalyst for industrial-level low-potential electrooxidation reactions.

Abstract

Electrooxidation of pollutants at potentials near or below the thermodynamic hydrogen evolution potential offers transformative opportunities for energy-efficient pollutant valorization and diverse energy devices. However, existing catalysts suffer from rapid deactivation due to the inevitable overoxidation. Herein, we present an amorphous phosphorus-doped CoFe₂O₄ catalyst that achieves industrial-level current densities (1 A cm⁻²) at ultralow potentials (0.06, 0.65, and -0.17 V vs. reversible hydrogen electrode) for hydrazine, sulfion, and borohydride electrooxidation, respectively, along with 400-hour stability at 300 mA cm⁻² in a hydrazine-assisted electrolyzer. Mechanistic studies reveal electron transfer from Co-P ligands to Co-O ligands, which enhances the involvement of Co-O ligands in low-potential electrooxidation while protecting Co-P ligands from overoxidation. Furthermore, more positive charges on Co centers lower the activation barrier for such pollutant electrooxidation. This work opens a paradigm for designing robust electrocatalysts by decoupling catalytic activity from oxidative deactivation.