Interfacial electrochemical kinetics

The first two chapters in this thesis introduce the fundamental knowledge underpinning electrochemistry and numerical simulation. The rest of the thesis comprises three parts: investigation of charge transfer at the electrode-electrolyte interface; a kinetic study of electrocatalytic reactions at micro- and nano-electrodes; and the evaluation of electrochemical detection of single enzymes. In the first part the inner-sphere electron transfer is discussed under different situations where the breakage or formation of the chemical bond, the reorganization of the solvent and the influence of the electrical double layer are taken into consideration. Two important half-cell reactions in the field of fuel cells, the hydrogen oxidation reaction and the oxygen reduction reaction, are taken as examples and discussed in Chapter 3 and Chapter 4. The second part focuses primarily on the influence of the electrode size and geometry on electrocatalytic reactions. The kinetics reflecting both the mass transport of the reacting species and the electrocatalytic reaction are investigated. The application of simulation enables the measurement of the kinetic parameters and the determination of rate-determining factors in different experimental situations. The hydrogen oxidation reaction on nanoparticles is investigated in Chapter 5. Homogeneous and heterogeneous ECâ (E: electrochemical step; Câ: catalytic step) reactions are discussed in Chapter 6, respectively. In the last section, the possible detection of single enzymes via the nano-impact electrochemical technique is explored in Chapter 7. The kinetics of the electrode system containing a freely-diffusing enzyme and a microelectrode is investigated and the experimental conditions required for the measurement of enzyme activity predicted.