During cyclic voltammetry, what effect does increasing the scan rate have on the peak current?

During cyclic voltammetry, increasing the scan rate results in an increase in the peak current. This phenomenon can be understood in terms of the relation between scan rate and mass transport dynamics.

As the scan rate is increased, the time available for the diffusion of reactants to the electrode surface is reduced. This means that more reactants are available for oxidation or reduction at the surface of the electrode during a given time period. The peak current (i) is proportional to the scan rate (ν) according to the Randles-Sevcik equation for a reversible redox reaction, which can be expressed as:

[ i = nFAD^{1/2}C\nu^{1/2} ]

In this equation, n is the number of electrons transferred, F is Faraday's constant, A is the area of the electrode, D is the diffusion coefficient, C is the concentration of the reactant, and ν is the scan rate.

Thus, an increase in scan rate leads to a greater peak current due to the enhanced transport of the reactant to the electrode surface, allowing for a more significant charge transfer process within the time frame of the voltammetric scan. This increased current reflects the faster dynamics of the electron transfer and mass