| Electrolyzed oxidizing water(EOW),as an innovative disinfectant characterized by its high efficiency,broad antimicrobial spectrum,and non-toxic residues,has been broadly used such as in health care,food safety,and agricultural production. However,current research on electrolyzed oxidizing water preparation is less and most simple process parameters for the study,which is the lack of key technology research and development.And we believe that the study of electrochemical properties of electro-catalytic material itself is the most important.,In addition to chlorine evolution reaction,there are a large number of oxygen evolution reaction occurs in the preparation of the electrolyzed water oxidation process. Moreover,how to deploy speed of the reaction between them and to improve the efficiency of the electrolysis to obtain optimal bactericidal efficiency of electrolyzed oxidizing water depend on study on the electrode material. In addition,besides improving the efficiency of the anodic reaction,the activity of cathodic hydrogen evolution reaction should also be enhanced. To solve the above problem,in this paper,we carry out the following studies.1. RuO2-SnO2 anode was prepared by thermal decomposition method. It could be seen that the crystal type of RuO2-SnO2 is the typical rutile structure by X-ray diffraction(XRD). The electrode surface exhibited the electrochemical characteristics of RuO2 through cyclic voltammetry(CV) without the characteristics of SnO2. The polarization curve of chloride evolution and oxygen evolution were further studied by Linear sweep voltammetry(LSV). With the current density of 70mA/cm2, the potential difference between chloride evolution and oxygen evolution was 368 mV for RuO2-SnO2 electrode,but 278 m V for RuO2 electrode. It suggests that the selectivity of chlorine evolution reaction of RuO2-SnO2 electrode is higher than that of RuO2 electrode. On this basis,electrolysis efficiency, available chlorine content, hypochlorous acid content and the acceleration life test of RuO2-SnO2 electrode were all studied in the actual preparation process of electrolyzed oxidizing water. The results showed that compared with RuO2,the electrolysis efficiency of RuO2-SnO2 electrode increased by 11.34% available chlorine content increased by 35.57% and hypochlorous acid content increased by 33.62%. And,what’s more,the acceleration life is increased 14 fold. Finally,by SEM characterization and electrochemical porosity calculations of RuO2-SnO2 electrode,it had suggested that the electrode surface is smooth and the internal porosity is large. So it can hinder theelectrolyte penetration into the inner of electrode, enhance the electrode corrosion resistance,and improve the service life.2. IrO2-TiO2 electrode was prepared by thermal decomposition in different proportions and different temperatures. It could be seen that the crystal type of IrO2-TiO2 is the typical rutile structure by X-ray diffraction(XRD). SEM characterization shows that with the Ir content increasing and the temperature rising, tablets diameter decreases gradually and degree of agglomeration reduces. By cyclic voltammetry characterization it shows that, compared with the IrO2 surface charge, TiO2 was added to make cyclic voltammetry electricity increase significantly, and there is the largest electricity cyclic voltammetry electricity in TiO2 molar fraction of 12.5%. Hydrogen evolution activity of different proportions material increases first and decreases with increasing TiO2 content as the optimal ratio of 14% and the apparent hydrogen evolution current of 43.38 m A / cm2.In addition,with increasing temperature,cyclic voltammetry power decreases,this is because as increasing of the preparation temperature,the surface of the grain electrode reunion grew constantly,resulting in the active sites of the electrode surface declining. But the temperature is conducive to better alloying between the two components. Research shows that when the preparation temperature is 550 ℃,there are the best activity of the hydrogen evolution,and the apparent hydrogen evolution current of 43.38 mA / cm2. In addition, by cyclic voltammetry around 1000 segments hydrogen evolution current contrast,hydrogen evolution proves Ir O2-Ti O2 good stability.3. Ir O2-FexOy binary oxides are prepared by thermal decomposition of in different proportions. It shows that they are mainly IrO2 rutile structure,and do not exhibit the characteristics of Fe oxide through XRD analysis,which indicate that Fe oxide described more uniformly dispersed in IrO2, and the degree of crystallinity is poor. SEM characterization shows that seeing from the figure,there is less difference in the different proportions IrO2-FexOy particle size,basically at 200-500 nm. But in high FexOy content,particle agglomeration between become serious; when FexOy content is reduced to10-20%, the reunion phenomenon is significantly improved. Through its hydrogen evolution activity study,results showed that in the Ir-Fe molar ratio of 9: 1,there is the maximum current of hydrogen evolution,reaching 70.71 mA / cm2,which is 11.2 times IrO2,and has a high hydrogen evolution stability. Through its analysis of chlorine and oxygen evolution activity study,they show that Ir O2- FexOy binary oxides,at pH = 1 of4 mol / NaCl solution,current of chlorine evolution is 233 mA / cm2 in a Ir-Fe molar ratio of9: 1, which is higher 14.6% on oxygen evolving current than IrO2 under the sameconditions, but also a corresponding increase in the current is 1.6 times Ir O2. So it is not obvious to improve the selectivity of the reaction of the chlorine evolution. However,we also note that the kind of electrode material deposited increases the activity of oxygen evolution,helps to make it a good oxygen evolution electrode material. |
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