cyclic voltammetry

1. CYCLIC VOLTAMMETRY
By: Halavath Ramesh
Department of Chemistry
Loyola College, Chennai
UNIVERSITY OF MADRAS

2. Cyclic voltammetry
• 1.cyclic voltammetry(cv) is an Eletrochemical
technique which measures the current that
develops in an electro chemical cell under
conditions where voltage is in excess of that
predicted by the nerst equation.cv is
performed by cycling the potential of a
working electrode and measuring the
resulting current.

3. Main points
• 1.A scar in the direction of more negative
potential is teruned a forward scan and oppositie
direction is called reverse scan.
• 2.General cyclic time range 1ms or less to 100s or
more.
• 3.The potential of the working electrode is
measured against a references electrode which
maintain a constant potential and the resulting
applied potential produces an excitation signal
such as that of figure1.

4. Introduction
• Cyclic voltammetry(cv) is an important and widely
used electro analytical technique.
• Although cv is infrequently used for quantitative
analysis , it finds wide applicability in the study of
oxidation/ reduction reaction.
• A cv experiment may use one full cycle, a partial cycle
or several cycles.
• During the cv experiment ,the current response of a
small stationary electrode in an unstirred solution is
excited by a triangular potential wave form.
• The triangular wave form produces the forward and
then the reverse scan.

5. Switching potential
• The potential is first varied linearly from +0.8v
to -0.15v versus a saturated calomel electrode
, at which point the scan direction is reversed
and the potential is returned to its original
value of +0.8v.
• The potential at which reversal takes place (
in this case -0.15v and +o.8v) are called
switching potentials.

6. 5
• 4.In the forward scan of figure1,the potential
first scans negatively, starting from a greater
potential(a) ending at a lower potential(d).
• 5.The potential extrem(d) is call the switching
potential.and is the point where the voltage is
sufficient enough to have caused an oxidation
or reduction of an analyte.
• 6.The reverse scan occurs from(d) to (g).

7. 6

8. 7
• 7.where the potential scans positively figur1
shows a typical reduction occuring from (A)
to(d) and an oxidation occuring from (d) to
(g).
• 8.A cyclic voltamgram is obtained by
measuring the current at the working
electrode during the potential scan.figur2 ,
shows a cyclic voltammogram resulting from a
single electron reduction and oxidation.

10. 8

11. Examples
• Another example experiment was performed on
copper sulfate
• using the CyclicVoltammetry test script. In this
example,
• cyclic voltammetry was used to plate copper on a
graphite
• working electrode and then strip it back again. This
chemical
• reaction was:
• (reduction) Cu2+ + 2e– ––> Cu (metallic)
• (oxidation) Cu ––> Cu2+ + 2e–

15. Triangular form
On x-axis potential.y.time

17. Instrumentation
1.A cv system consists of an
electrolysis cell,working
electrode,counter
electrode,reference electrode,and
electrolytic solution.

19. mm

20. 1. CYCLIC VOLTAMMETRY HAS BECOME
AN IMPORTANT AND WIDELY USED
ELECTRO ANALYTICAL TECHNIQUES IN
MANY AREAS OF CHEMISTRY.
10. Applications.
*It is used for identical
tools.
*.It is also used in cellular
biology.

21. RESEARCH AREA IS IN
ELECTROCHEMISTRY MODIFIED THE
ELECTRODES

22. References
• 1.Instrumental methods of chemical
analysis.(Analytical chemistry)
• Author.DR.B.K.SHARMA
• Skoog, D.; Holler, F.; Crouch, S. Principles of
Instrumental Analysis 2007
• Kissinger, P. T., Heineman, W. R., “Cyclic
Voltammetry,” Journal of Chemical Education, 60,
702 (1983).

23. ANY QUESTIONS
AND
SUGGESTIONS

24. “GOOD SCIENCE IS GOOD
PLANNING”