Structured and graphitized boron doped diamond electrodes: Impact on electrochemical detection of Cd2+ and Pb2+ ions

Abstract

Here we introduce the structuring of boron doped diamond (BDD) electrodes using a self-organised mask and reactive ion etching (RIE) in oxygen plasma for electrochemical measurements of selected metal ions. The samples were analysed by SEM, Raman and X-ray photoelectron spectroscopy. The electrochemical performance of structured BDD was compared to as-grown BDD and standard glassy carbon (GC) electrodes employing standard cyclic voltammetry and differential pulse anodic stripping voltammetry. Separate and simultaneous detection of Cd2+ and Pb2+ ions is discussed in relation to the electrode morphology and content of graphitic phase. To determine trace amounts of metal ions we evaluated the repeatability of measurements, which is statistically expressed as the relative standard deviation (RSD) of consecutive determinations. Based on RSD data, the most suitable candidate for the separate detection of Cd2+ and Pb2+ ions was found the structured BDD electrode consisting of nanotips and small nanorods, respectively. Two times better RSD was found for the structured BDD than for the as-grown BDD electrode. Electrochemical measurements provided in the complex mixture consisting both of Cd2+ and Pb2+ ions revealed the small BDD nanorods as the most suitable surface morphology to separate recognition of Cd2+ and Pb2+ ions.