A Quantitative Measurement Technique for Anodic Corrosion of BDD Advanced Oxidation Electrodes

Electrochemical advanced oxidation (EAO) systems are of significant interest due to their ability to treat a wide range of organic contaminants in water. Despite their popularity, all studies to date that examine anodic corrosion of BDD electrodes are qualitative, using techniques such as scanning electron microscopy, electrochemistry, and spectroscopy. In this work we present a new method to quantify anodic corrosion and determine average corrosion rates as a function of solution composition, current density and BDD material. The method uses white light interferometry (WLI), in conjunction with BDD electrodes integrated into 3D-printed flow cells, to measure three-dimensional changes in surface structure pre- and post-anodic corrosion over a 72-hr period. It is equally applicable to both thin film BDD and much thicker, freestanding BDD. As WLI lends itself to large area measurements, data are collected over geometric areas of 0.5 cm2. In particular it is shown that the addition of 1 M acetic acid to a 0.5 M potassium sulfate solution results in an increase in the average corrosion rate of ~×60 (for freestanding polished BDD). In the same solution, thin film BDD is found to corrode ~×2 faster than freestanding polished BDD. This methodology also represents an important step forward for the prediction of BDD electrode lifetimes in a laboratory setting for a wide range of EAO applications.