Preparation of Acidic Electrolyzed Water by a RuO2@TiO2 Electrode with High Selectivity for Chlorine Evolution and Its Sterilization Effect

The food hygiene problems caused by bacterial biofilms in food processing equipment are directly related to human life safety and health. Therefore, it is of great strategic significance to study new food sterilization technology. An acidic electrolyzed water (AEW) disinfectant is an electrochemical sterilization technology which has the characteristics of wide adaptability, high efficiency, and environmental friendliness. However, since the sterilization efficiency of AEW for biofilrns is not ideal, it is necessary to increase the available chlorine content (ACC) in AEW. A feasible method to increase the ACC is by increasing the chlorine evolution reaction (CER) selectivity of the electrode for AEW preparation. In this paper, the RuO2@TiO2 electrode was prepared by thermal decomposition combined with high-vacuum magnetron sputtering. Compared with the oxygen evolution reaction (OER) activity of an ordinary RuO2 electrode, the OER activity of the RuO2@TiO(2 )electrode is significantly reduced. However, the CER activity of the RuO2@TiO2 electrode is close to the OER activity of RuO2. The CER mechanism of the RuO2@TiO2 electrode is the second electron transfer, and the OER mechanism is the formation and transformation of OHads. The potential difference between the CER and OER of the RuO2@TiO2 electrode is 174 mV, which is 65 mV higher than that of the RuO(2 )electrode, so the selectivity of the CER of the RuO2@TiO2 electrode is remarkably improved. During the preparation of AEW, the ACC obtained with the RuO2@TiO2 electrode is 1.7 times that obtained with the RuO2 electrode. In the sterilization experiments on Escherichia coli and Bacillus subtilis biofilms, the logarithmic killing values of AEW prepared the by RuO2@TiO2 electrode are higher than those of AEW prepared by the RuO2 electrode.