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 RuO_x 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.