8: Hydrodynamic Electrodes

So far in this book we have considered the voltammetric response of stationary electrodes in a stationary solution in which transport to the electrode surface occurs solely by diffusion and in accordance with Fick’s Laws (Chapter 3). In this chapter, we explore voltammetry in which defined diffusion is augmented by convection. There are two main reasons why convection is introduced. First, the additional means of transport gives higher current densities, especially where macroelectrodes are concerned. Indeed, we show later in this chapter that insonation of a macroelectrode can confer it with the mass transport properties of a micron-sized electrode with the benefits for the study of fast processes established in Chapter 5 for microelectrodes. Second, the presence of significant convection changes the voltammetric response from the characteristic peak shaped current–voltage curves typical of voltammetry under planar diffusion conditions into the steady-state response typical of a hydrodynamic electrode shown in Fig. 8.1.