Efficient electrocatalytic H₂O₂ activation over nitrogen-doped carbon encapsulated Co₃O₄ for drinking water disinfection

Waterborne diseases claim a million lives each year in areas without adequate centralized water treatment. Electrocatalytic •OH production presents a promising avenue for decentralized water disinfection. However, existing catalysts are limited by low activity at neutral pH and the risk of metal leaching. We have developed a chainmail catalyst, N-doped carbon (NC) encapsulated Co₃O₄ (NC@Co₃O₄), for efficient electrocatalytic H₂O₂ activation. Co₃O₄ extracts electrons from NC, thus enhancing the affinity of O atom of H₂O₂ at the electron deficient carbon sites in NC and promoting the cleavage of O−O bonds. Consequently, the •OH generation rate catalyzed by NC@Co₃O₄ was 6.5 times of that by NC. Integrating the NC@Co₃O₄ into a flow-through electrochemical reactor as cathode, a voltage of only 2 V drove the device to achieve more than 6.8 logs (99.99998 %) of Escherichia coli inactivation in tap water. This work provides an energy-efficient, green, and safe solution for decentralized water disinfection.