An Electrochemical System for Gaseous ClO2 Generation Using TiO2 Nanorod Array Cathodes Toward Fruit Preservation

The efficient on-demand generation of ClO2 is critical for disinfection and food preservation. However, the development of safe and efficient strategies for gaseous ClO2 production remains challenging. Herein, we report a stable and efficient electrochemical system for ClO2 production based on rutile TiO2 nanorod arrays (TiO2 NAs). Electrochemical optimization suggests that a cathodic potential of −0.10 V (vs. Ag/AgCl) in an electrolyte solution of 1 M NaClO3 with 5 M H2SO4 achieves the highest ClO2 production efficiency. Mechanistic studies reveal that ClO2 generation proceeds via an O2-induced pathway, in which electrochemically generated H2O2 from 2-e− O2 reduction reacts in situ with ClO3− to form ClO2, eliminating the need for external H2O2 storage and significantly improving operational safety. Furthermore, when decorated with RuOx nanoparticles, TiO2 NA cathodes achieve enhanced catalytic performance and excellent stability. In addition, the generated ClO2 in the electrolyte solution can be delivered via gas pumping. This ClO2 atmosphere exhibits antibacterial efficiencies exceeding 99% against Escherichia coli and Staphylococcus aureus, and significantly reduced weight loss and preserved fruit hardness in longan samples during 8 days of storage. Overall, this work presents a safe, efficient approach for ClO2 generation with strong potential for practical disinfection in the food preservation field.