Redox‑Gated Molecular Switching of CO ₂ Self‑Poisoning on Quinone Electrocatalysts Enables In Situ Self‑Regeneration

ABSTRACT

Quinone‐based metal‐free electrocatalysts offer a sustainable route for oxygen activation and water purification, yet their persistent activity decay has remained poorly understood. Here, we identify mineralization‐derived CO ₂ as the major cause of a previously overlooked self‐poisoning pathway in quinone‑based electrocatalysts: CO ₂ accumulates at the electrode–electrolyte interface and forms stable carbonate adducts with reduced quinone moieties, blocking the active sites for two‐electron oxygen reduction to H ₂ O ₂ and consequently suppressing ·OH generation through the cascade oxygen‐reduction pathway. Electrochemical analysis further reveals that CO ₂ adduction reorganizes the native quinone redox transitions into potential‐dependent carbonate‐bound states, allowing the occupied quinone centers to be reversibly regenerated by oxidative pulses. Leveraging this principle, we developed a pulsed electrocatalytic strategy that periodically reoxidizes the quinone catalyst in situ, dynamically reversing CO ₂ poisoning without requiring chemical regenerants or thermal treatment. Across structurally diverse pollutants at neutral pH, this strategy accelerates degradation kinetics by up to 725.3% and retains up to 93.6% of its 2 h diclofenac removal efficiency after 12 h of continuous operation. More broadly, the redox‐gated CO ₂ switching mechanism provides a generalizable design paradigm for mitigating CO ₂ ‐induced deactivation in electrocatalytic systems prone to local CO ₂ buildup, including CO ₂ electrolysis, electrosynthetic biomass conversion, and electrochemical nitrogen fixation.