What is diffusion current and migration current?
These two processes are inexorably intertwined in the flow of current. There are three basic mechanisms of mass transport: Diffusion – defined as the spontaneous movement of any material from where it is to where it is not. Migration – the movement of charged particles in an electric field.
What is diffusion current in voltammetry?
In pulse voltammetry, the applied potential consists of a linear ramp with superimposed voltage pulses and the current is measured before and at the end of each pulse. Diffusion current is the difference between the limiting current and the residual current.
What is difference between diffusion current and drift current?
Hint: Drift current is the electric current due to the movement of charge carriers under the impact of an outer electric field, while diffusion current is the electric current due to the distribution of carriers, pointing to a change in carrier collection.
What is difference between drift current and diffusion current?
How does diffusion current work?
The process by which, charge carriers (electrons or holes) in a semiconductor moves from a region of higher concentration to a region of lower concentration is called diffusion.
What do you mean by diffusion current?
This is the current which is due to the transport of charges occurring because of non-uniform concentration of charged particles in a semiconductor. The drift current, by contrast, is due to the motion of charge carriers due to the force exerted on them by an electric field.
What is the current when diffusion is fast?
When the diffusion is very fast, the current depends only on the kinetics. Because of the fast diffusion, the concentration at the surface of the electrode is equal to the concentration in the bulk solution: . The reaction rates of the oxidation direction depend on the applied potential at the electrode:
How does diffusion affect the kinetics?
When the kinetics are extremely fast, the phenomenon is controlled by the diffusion (mass transport) of the species that enters or leaves the electrode surface. This Demonstration shows the current on the left (blue) when controlled by kinetics and on the right (red) when controlled by diffusion.
What are the limiting mechanisms for electrochemical reactions on electrodes?
An electrochemical reaction on the surface of an electrode can occur by two limiting mechanisms: the reaction is controlled by kinetics and the reaction is controlled by the diffusion of the electroactive species.
How does current pass through an electrochemical cell?
Current through an electrochemical cell passes as a result of motion of ionic (electrically charged) species that are contained in the electrolyte (ionic conductor). This motion of ions (current) occurs under the influence of different forces (potential gradients).