摘要
通电电流密度及极化时间对Ag/AgCl电极性能影响较大,其取值争议较大。将Ag棒放入0.1 mol/L的HCl溶液中进行电解,电流密度为0.5,1.0,2.0,3.0,4.0 m A/cm^2,通电时间为0.5,1.0,1.5,2.0,2.5,3.0 h。在电极电解过程中,记录电位-时间曲线。通过SEM观察不同条件所得电极的表面形貌,并用EDS分析其元素组成。结果表明:随着极化时间的增长,Ag棒表面电解产物增多,在恒定通电电流密度条件下,电解产物的生成增大了电极的电阻,从而导致电极电位随极化时间的增长而增大;极化时间相同时,通电电流密度越大,电解产物生成速度越快,电极电位越高,多层电解产物的穿插生成导致电极表面粗糙,并伴有小坑等缺陷出现;电解产物主要由Ag和Cl组成;当电流密度小于或等于1.0 m A/cm^2时,电极电位增长缓慢,电解产物缓慢生长,电极表面较为致密,通电电流密度为0.5 m A/cm^2的电极电位在9 800 s左右出现骤降,为获得较为致密和性能稳定的Ag/AgCl电极,建议阳极极化法制备Ag/AgCl电极的通电电流密度为0.5 m A/cm^2,极化时间为2.5 h(9 000 s)。
Ag electrade was electrolyzed in 0.1 mol/L HC1 solution at 0.5,1.0,2.0,3.0,4.0 mA/cm^2 of current density,for 0.5,1.0,1.5,2.5,3.0 h of polarization time.During the electrolytic process,the potential-time curve was recorded.Subsequently,SEM was used to observe the surface morphology of different electrodes,and EDS was used to analyze the element composition.Results showed that with the increase of polarization time,the electrolytic products on the surface of Ag electrode increased,and at a constant current density,the formation of electrolytic products improved the resistance of Ag electrode,leading to the increase of potential of the electrode with polarization time extending.When the polarization time was conformed,the greater the current density,the faster the generation of electrolytic products and the higher the electrode potential.Meanwhile,the crossing formation of multilayer electrolysis products caused that the electrode surface became rougher,accompanied with some defects such as pits.The electrolysis products were composed of Ag and Cl.When the current density was lower than or equal to 1.0mA/cm^2,the electrode potential increased slowly and the formation of electrolytic products was slow,which led to that surface of electrode became much denser.With the current density of0.5 mA/cm,the electrode potential dropped suddenly when the time was 9 800 s.Therefore,in order to obtain a more compact and stable performance of Ag/AgCl electrode,the recommended conditions were 0.5 mA/cm^2 of current density and 2.5 h(9 000s) of polarization time of 2.5 h(9 000 s).
出处
《材料保护》
CAS
CSCD
北大核心
2016年第12期22-25,共4页
Materials Protection
基金
国家重点基础研究发展计划“973”项目(2015CB655100)
国家自然科学基金国际合作与交流项目(51420105015)资助
