Chemistry Reference
In-Depth Information
Current
i
Anodic
Potential
-E
+E
i
Cathodic
1.2
Sign conventions used in this topic.
origin). Whatever convention is used, the axes should be clearly labelled so
that, in principle, it should be clear to the reader what is meant and how
the data should be converted to other conventions used in the electro-
chemical literature.
1.4
Classification of electrochemical methods
It is the aim of this chapter to explain the basic requirements for perform-
ing electrochemistry, such as equipment, electrodes, electrochemical cells
and boundary conditions to be respected. The following chapter focuses on
the basic theory of charge transfer at the electrode-electrolyte solution
interface and at transport phenomena of the analyte towards the electrode
surface. In Chapter 3, a theoretical overview of the electrochemical methods
applied in the work described in this topic is given.
Essentially, the items mentioned above will be described as a function of
the type of electrochemical method. The methods described and used in the
work of this topic can therefore be divided into three groups:
•
Potentiometric methods
: in potentiometric methods, the equilibrium
potential of the working electrode (see section 2.2) is measured against
the potential of a reference electrode. That potential results from an
equilibrium established over the electrode-electrolyte interface and
provides information about the analyte taking part in this equilibrium.
•
Voltammetric methods
: in these methods, a potential is applied to the
working electrode using a three-electrode setup (see section 1.6).
The electrical current, resulting from charge transfer over the
electrode-electrolyte interface, is measured and reveals information
about the analyte that takes part in the charge transfer reaction. The
potential applied can be constant (chronoamperometry, section 2.5),
varied linearly (cyclic voltammetry, section 2.3) or varied in other ways
(Chapter 2).
