Electrocatalytic Generation of Singlet Oxygen via ROS-Mediated Redox Chain Reaction for Efficient Disinfection

The risk of harmful microorganisms to ecosystems and human health has stimulated exploration of singlet oxygen (O-1(2))-based disinfection. It can be potentially generated via an electrocatalytic process, but is limited by the low production yield and unclear intermediate-mediated mechanism. Herein, we designed a two-site catalyst (Fe/Mo-N/C) for the selective O-1(2) generation. The Mo sites enhance the generation of O-1(2) precursors (H2O2), accompanied by the generation of intermediate (HO2)-H-center dot/O-center dot(2)-. The Fe site facilitates activation of H2O2 into (OH)-O-center dot, which accelerates the (HO2)-H-center dot/O-center dot(2)- into O-1(2). A possible mechanism for promoting O-1(2) production through the ROS-mediated chain reaction is reported. The as-developed electrochemical disinfection system can kill 1 x 10(7) CFU mL(-1) of E. coli within 8 min, leading to cell membrane damage and DNA degradation. It can be effectively applied for the disinfection of medical wastewater. This work provides a general strategy for promoting the production of O-1(2) through electrocatalysis and for efficient electrochemical disinfection.