Plane-recessed disk electrodes and their arrays in transient generator–collector mode: The measurement of the rate of the chemical reaction of electrochemically generated species

A novel electrode geometry is proposed in which a disk microelectrode is recessed below a second electrode which covers an entire plane. Potential step experiments on such plane-recessed disk electrodes and arrays of these electrodes are considered. The recessed disks act as a generator and a plane electrode above acts as a collector. Electrochemical reactions at the generator electrode are assumed to be followed by chemical reaction. Both first order (EC1) and second order (EC2) mechanisms are considered. Current transients are found to be sensitive to the diffusion coefficient of both the reduced and oxidised species as well as to the rate of the chemical reaction and its mechanism. The rate constant of the chemical reaction can be measured over a range of six orders of magnitude. The rate of the second order chemical reaction can be measured up to the limit of diffusion controlled reaction.