Electrochemical behaviour of nanomaterials

This thesis reports the electrochemical modification of boron doped diamond with metal nanoparticles and investigates the resulting electrochemical behaviour for common analytes in the food industry, especially in terms of fundamental mechanistic analysis. The first chapter gives a brief introduction to boron doped diamond including its synthesis, properties, and electrochemical applications. The second chapter introduces the experimental techniques used in this thesis and the theory behind them, particularly the basic principles of electrochemistry. Chapter 3 investigates the electro-oxidation reaction mechanism of sulphite on gold macroelectrodes and on gold nanoparticle array modified boron doped diamond electrodes. A facile procedure which controls the morphology and size of gold nanoparticles is established by pulse deposition. The kinetics of sulphite oxidation on gold macroelectrodes and gold nanoparticle modified substrates are examined, and experimental voltammetry and simulation for both cases are combined to confirm the mechanism. Chapter 4 extends the electrodeposition methods for gold nanoparticles to investigate the electrocatalytic activity towards nitrite oxidation. Two electrochemical techniques including cyclic voltammetry and pulse depositions for gold deposits are used. The resulting modified electrodes are compared and optimised for electroanalytical detection of nitrite, and herein the relationship between gold particles and the analytical performance are correlated. Chapter 5 analyses the hydrogen peroxide electro-reduction mechanism on silver nanoparticle modified boron doped diamond electrodes. The disproportionation of hydrogen peroxide and the role of oxygen reduction during the process are examined, and a mechanism is proposed and confirmed by voltammetric analysis plus full mechanistic simulation. Chapter 6 further develops the previous established mechanism project to explore different effects on the electrocatalytic performance for hydrogen peroxide reduction. A number of factors including nanoparticle loading, size, and electrode decoration methods are investigated to provide implication insights for nanoparticle based electroanalysis. Finally, Chapter 7 draws overall conclusions.