Metal modified boron doped diamond electrodes and their use in electroanalysis

Abstract

The experimental work discussed in this thesis explores the effects of metal modification on the electroanalytical ability of boron doped diamond electrodes. Boron doped diamond (BDD) electrodes have found increased application to electroanalysis in the past two decades, yet relatively little of the literature is focused on metal, nano and microparticle modification of the substrate. In this thesis three metals have been used to modify the BDD electrode; bismuth, antimony and nickel.Bismuth and antimony nanoparticle modified BDD electrodes were directly compared to unmodified BDD and a bulk bismuth electrodes in the determination of trace levels of cadmium and lead using anodic stripping voltammetry. In both instances, the modified electrode allowed for the simultaneous determination of each analyte that was otherwise unattainable at the unmodified BDD electrode.The nickel modified BDD (Ni-BDD) electrode was used in the determination of organic analytes, namely glucose, methanol, ethanol and glycerol. The nickel nano and microparticle electrodes gave the characteristic Ni(OH)₂/NiOOH redox couple in alkali pH, the oxidised form of which (NiOOH) catalysed the oxidation of the organic analytes. The chapter on glucose sensing with the Ni-BDD electrode is preceded by an extensive literature review on the advances of non-enzymatic glucose sensing, and the application of catalytic metals and nanomaterials in this field.Throughout the course of this DPhil, there has been a collaborative project between Asylum Research and myself within the Compton group to develop a commercial electrochemical atomic force microscope (EC-AFM) cell. The aim was to produce an adaptable EC-AFM cell capable of dynamic electrochemical experiments whilst simultaneously or instantaneously acquiring an AFM image of the modified surface, in-situ. This project was successful, and the EC-AFM cell has contributed to a number of chapters in this thesis, and has now been commercialised.