通电电流密度对氧化铱pH电极性能的影响

Effect of current density on the performance of iridium oxide pH electrode

在一般大气环境、带有酸性气体和酸性液体的工业环境中,混凝土中性化是引起混凝土内部钢筋锈蚀破坏的主要因素。为了能够及时、准确地监测钢筋混凝土内部的pH值,用恒电流沉积法制备了氧化铱pH电极,研究了不同电流密度下pH电极的微观形貌、响应时间、稳定性和能斯特响应。结果表明,随着沉积电流密度增加,氧化铱pH电极表面更加粗糙,并且沉积层表面的白色K_(2)CO_(3)颗粒变多。沉积电流密度为1 mA/cm^(2)时,制备的电极响应时间最短为67 s,电极电位迅速达到稳定并且电位波动不超过20 mV。此外,1 mA/cm^(2)电流密度制备的电极能斯特响应曲线的斜率(74.91 mV/pH)也优于其他电流密度下制备的电极。

In general atmospheric environment and industrial environment with acidic gas and acidic liquid,the neutralization of concrete is the main factor that causes corrosion and damage of steel bars in concrete.In order to be able to timely and accurately monitor the internal pH value of reinforced concrete,galvanostatic deposition method was used to prepare an iridium oxide pH electrode,and the microscopic morphology,response time,stability and Nernst response of the pH electrode under different current densities were studied.Results show that as the deposition current density increases,the surface of the iridium oxide pH electrode becomes rougher and the white K_(2)CO_(3) particles on the surface of the deposition layer increase.When the deposition current density is 1 mA/cm^(2),the shortest response time of the prepared electrode is 67 s,the electrode quickly stabilizes and the potential fluctuation does not exceed 20 mV.In addition,the Nernst response slope(74.91 mV/pH)of the electrode prepared at a current density of 1 mA/cm^(2) is also better than that of electrodes prepared at other current densities.