Preparation And Investigation Of Long Life DSA For On-site Chlorine Evolution

Marine cooling water system was attacked by both corrosion and biofouling, and biofouling seems to be even more intractable. Electrochemical on-site chlorine evolution was regarded as the most effective antibiofouling way for industry cooling water system. Anode material is the core component of chlorine evolution system, and the electrochemical stability of anode directly influenced the reliability of chlorine evolution system. The stability of anode has been the biggest problem.Address these issues, thermal decomposition method was used to prepare Ti/RuO2-TiO2-SnO2 anode. SEM, EDX, EIS, XRD, chlorine evolution and oxygen evolution potential measurement, polarization curve and accelerate life time test were applied on investigate the anode coating's properties and deactivate mechanism. The enhancement of interlayer on electrochemical stability of anodes was studied, and working mechanism of interlayer was also studied. An excellent high electrochemical stability anode was prepared for chlorine evolution.Ti/RuO2-TiO2-SnO2 anode showed excellent electrochemical activity and selectivity for chlorine evolution. The chlorine evolution potential of the anode was 1.094V and the differential potential for chlorine and oxygen evolution was 337mV. While the electrochemical stability of anode was not enough, and accelerate life time was only 7.5h under 2A·cm-2. Anode deactivation mechanism indicate that, in accelerate life time test, active components of Ti/RuO2-TiO2-SnO2 anode coating was kept stable, without solution phenomenon. The main deactivate mechanism was the form of insulate TiO2 between surface coating and titanium base.Thermal decomposition temperatures influence the properties of IrO2-MnO2 interlayer. IrO2-MnO2 interlayer sintering under 450℃shows high crystallinity and compact morphology, and electrochemical porosity turned to be lowest about 38.3%. IrO2-MnO2 and IrO2-Co3O4 interlayer prepared under 450℃shows a compact structure, added to Ti/RuO2-TiO2-SnO2 anode as interlayer enhance the electrochemical stability greatly, under the condition of 2A·cm-2 current density, accelerate life time extend to 995h and 332h. While SnO2-Sb2O3 and SnO2-Sb2O3-MnO2 interlayer prepared under 500℃with a compact structure did not improved the electrochemical stability, accelerate life time were just 14.7h and 23h. Interlayer working mechanism shows:Oxygen evolution was occurred on IrO2-MnO2 and IrO2-Co3O4 coating with a very low potential, while SnO2-Sb2O3 and SnO2-Sb2O3-MnO2 coating show sluggishness for oxygen evolution. Water molecular can be adsorbed on anode surface, under the catalysis of activate site, active oxygen can be formed, and could transferred to inner of the anode, induced oxidation of titanium base. When the absorbed oxygen transferred near interlayer, active oxygen atom will be consumed oxygen evolution occurred.