Surfactant-tolerant cathodes for electrochemical generation of hydrogen peroxide for wastewater treatment

Cathode materials based on carbon substrates are of high interest for the electrochemical generation of hydrogen peroxide (H₂O₂) for wastewater treatment because of their low cost, chemical stability and high selectivity. However, the H₂O₂ selectivity of carbon materials can be significantly reduced in presence of surfactants, which are frequent contaminants in wastewater. Therefore, the development of surfactant-tolerant cathode materials is highly important. In this paper, composite electrodes comprising of polytetrafluoroethylene and carbon black on a carbon felt substrate were prepared. The effect of sodium dodecyl sulphate on the electrode activity was investigated. It was found that the electrodes prepared with high bulk density carbon black featured a high H₂O₂ Faradaic efficiency of 95% in surfactant-free solutions. These electrodes also showed significant surfactant tolerance having a 70% Faradaic efficiency in the presence of 1 mM sodium dodecyl sulphate. The enhanced surfactant tolerance is attributed to the hydrophobic properties of the electrode surface.