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

Abstract

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.