A facile solution to mature cathode modified by hydrophobic dimethyl silicon oil (DMS) layer for electro-Fenton processes: Water proof and enhanced oxygen transport

Water flooding in the microporous cathode is poisonous but inevitable for oxygen reduction reaction (ORR) in electro-Fenton (EF) processes. To meet this challenge, a facile modification was reported to stabilize performance of cathode through the infiltration process, which selecting superior CB-PTFE electrode as backbone and dimethyl silicon oil (DMS) as maturation layer. Characterized by FE-SEM, EDS, BET, XRD, the matured cathode was proved to be wrapped uniformly by DMS. Electrochemical performances of cathodes were evaluated by CA , CV , EIS and CP measurements in oxygen “starvation” condition. These results proved that the maturation layer improved the electrocatalysis on 2 e − ORR, the service lifetime from 1.68 h to 18.34 h, the working range of current density from 70 to 110 A m −2 and reduced the oxygen diffusion resistance from 74.23 to 8.07 Ω. Besides, H 2 O 2 generation and oxygen utilization of 2%DMS cathode respectively reached 126.7 mg L −1 and 83.49% in 60 min, which were rarely influenced by pH and aeration rate even after water flooding process. 2%DMS layer served as the accelerated oxygen transport channel can explain the enhanced oxygen transport. The simulated contaminated solution containing a fungicide-flutriafol (FTF) was obtained 100% removal in about 40 min and 48.88% TOC removal in 2 h. The lifetime tests revealed much more stable decay of FTF under the broader operational condition.