Cyclic voltammetry (CV) is an electrochemical technique used to investigate the redox properties of a chemical species. It involves measuring the current response of an electrochemical cell as a function of the applied potential. The setup for cyclic voltammetry typically consists of a working electrode, a reference electrode, and a counter electrode—all immersed in an electrolyte solution. The working electrode is where the redox reaction of interest occurs, while the reference electrode provides a stable potential reference, and the counter electrode completes the circuit for the current flow.
The process begins by setting a starting potential at the working electrode, usually at the point where no electrochemical reaction occurs. The potential is then linearly ramped in one direction until it reaches a preset value. At this point, the direction of the potential sweep is reversed, moving back toward the initial potential. When the applied potential causes an electrochemical reaction (either oxidation or reduction) at the electrode surface, it results in current flow. The resulting cyclic voltammogram plots current versus applied potential, showing anodic and cathodic peaks. Anodic peaks correspond to the oxidation process, while cathodic peaks represent the reduction process.
Cyclic voltammetry investigates the redox property of a chemical system via an electrochemical cell.
This cell comprises working, reference, and counter electrodes immersed in an electrolyte containing the analyte of interest.
A triangular potential waveform is applied to the working electrode, sweeping the potential between an initial value, a vertex potential, and back to the starting value.
The potential starts at an initial value where no redox reaction occurs and then sweeps across to a value where the analyte undergoes either reduction or oxidation at the working electrode surface.
The potential is then reversed and swept back to its initial value allowing the reverse reaction to occur.
The current measured from the redox reaction plotted against the potential yields a cyclic voltammogram with two distinct peaks: an anodic peak for oxidation and a cathodic peak for reduction.
The peak positions indicate the redox potentials, while the peak currents are proportional to the concentration of the analyte.
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