Efficient chlorine evolution of CuO modified RuO2 electrode and its application in preparation of electrochemical disinfectant

Abstract

Electrochemical chlorine evolution reaction (CER) is one of the most important practical applications of electrochemical reaction, which can be used for electrochemical disinfection. The electrochemical disinfectant of acidic electrolyzed water (AEW) is obtained by electrolyzing extremely dilute chlorine-containing solution in ion-exchange membrane electrolyzer. In the anode area, HClO is produced by CER, which has a strong bactericidal effect. Due to the low concentration of chloride ion, it is necessary to improve the CER selectivity of the electrode in order to improve the efficiency of chlorine electrolysis. In this paper, CuO/RuO2 electrode was prepared by the two-step thermal decomposition method, and the surface morphology and electronic structure of RuO2 electrode were modified. Compared with the ordinary RuO2 electrode, the CER activity of CuO/RuO2 electrode is improved. For the oxygen evolution reaction (OER), the activity of CuO/RuO2 electrode is significantly lower than that of RuO2 electrode. The CER mechanism of CuO/RuO2 electrode is the second electron transfer, and the OER mechanism is the formation and transformation of OHads. The potential difference between CER and OER of CuO/RuO2-3 electrode is 105 mV, which is 52 mV higher than that of RuO2 electrode, so the selectivity of CER of CuO/RuO2 electrode is remarkably improved. During the preparation of AEW, the HClO of AEW2 (prepared by CuO/RuO2-3 electrode) is 0.72 mmol/L, which is 2.5 times that of AEW1 (prepared by RuO2 electrode). In the sterilization experiments on E. coli and B. subtilis, the germicidal efficacy of AEW2 (3.71 and 2.99 log10 CFU/mL) is obviously superior to that of AEW1 (0.76 and 0.61 log10 CFU/mL).