CHEM 555, Electroanalytical chemistry

Fall 1998

Class syllabus Fall 1998
DigiSim® suggested topics
DigiSim® dates
Topics for in-class presentations
Time line of events
Term paper

Time line of events

The following are the events scheduled for the class. Some require time to prepare. Plan accordingly, so that you are ready.

CHEM 555, Electroanalytical chemistry Fall 1998   

Class schedule: Tuesday and Thursday, 9:30-10:45, FR 205

Dr. Petr Vanýsek, Instructor, FW 418, e-mail: pvanysek¤niu.edu, ph.: 815-753-6876

Office hours: Tuesday 15:00-17:00 or by appointment

Textbooks:    A. J. Bard and L. R. Faulkner: Electrochemical methods, Fundamentals and applications, Wiley, New York 1980.

Recommended book: (Note, the bookstore failed to order this text.) P. A. Christensen, Techniques and mechanisms in electrochemistry. Chapman and Hall, 1994

Supplementary material: Oldham and Myland, Fundamentals of Electrochemical Science, Academic press 1994; Bockris and Khan: Surface Electrochemistry, Plenum 1993. , W. Schmickler, Interfacial Electrochemistry, Oxford University Press 1996.

1. Place of electrochemistry in modern science, history of electrochemistry
2. Concepts of electricity, electronics, equilibria in solutions
3. Thermodynamics in electrochemistry, kinetics
4. Mass transfer by diffusion and migration
5. Potential step methods
6. Potential sweep method
7. Cyclic voltammetry
8. Controlled current and hydrodynamic techniques
9. Impedance measurements
10. Bulk electrolysis
11. Kinetics of electrode processes
12. Structure of the double-layer
13. Electrochemical instrumentation
14. Spectrometric and photochemical experiments
15. Recent developments in electroanalytical chemistry

Grading:

DigiSim project 10 %

Class presentation 10 %

Mid-term examination (October 6) 25 %

Term paper 25 %  (due December 1)

Final examination (December 7, 10:00-11:50) 30 %

100-85 % - A, 85 - 75 % - B, 75 -65 % - C, 65 - 55 % - D, less than 55% - F

The class presentation will be a topic of modern electrochemistry (we will teach each other, active class participation will be encouraged), selected within the first three weeks of the course. The DigiSim project is essentially an experiment done using a Windows based computer program. You can copy the program on your own machine, but to run it, you will need a hardware key (dongle). We have only one available, so some advance scheduling will be required.

Chemistry 555

Topics for projects with DigiSim program

1. Chemical reaction preceding electrochemical (electrode) reaction. Investigate the conditions under which the effect of the chemical reaction will be apparent. I. e., there will be some conditions, when the system will look as diffusion controlled, but eventually, a deviation from this behavior will be seen.

2. Chemical reaction following electrochemical (electrode) reaction. Investigate the conditions under which the effect of the chemical reaction will be apparent. I. e., there will be some conditions, when the system will look as diffusion controlled, but eventually, a deviation from this behavior will be seen.

3. Voltammetry of two reversible species. Under ideal conditions a number of species can be simultaneously observed. However, concentrate on the less favorable conditions. Find the smallest difference in standard potentials when two separate peaks can still be distinguished. How is this smallest value related to the relative concentration of the two species? Determine the smallest value of standard potential difference as a function of concentration ratio - perhaps present a 3-dimensional plot.

4. Geometry and response. The program allows to consider several geometries of electrodes. Compare the performance (an a reversible system) for a planar electrode and a wire electrode (with the same geometrical are). Find conditions under which the response of the two geometries becomes different.

5. Geometry and response. The program allows to consider several geometries of electrodes. Compare the performance (an a reversible system) for a planar electrode and a hemispheric electrode (with the same geometrical are). Find conditions under which the response of the two geometries becomes different.

6. Microelectrode vs. macroelectrode. Compare the response of microelectrode (ca. 10 µm dia) with a 1-square cm electrode. You will need to scale the currents, obviously, But once you do so, find conditions under which the behavior of the small electrode starts to deviate form the large electrode. What are the conditions?

7. Effect of kinetically slow electrochemical process. Investigate a redox reaction for several different (over a number of orders of magnitude) rate constants, from fast to slow. (Decide what is fast and slow). Find the general trends and response.

8. Prepare an interesting set of results demonstrating the effect of charging current on ideally polarizable electrode. Note: The program does not allow explicitly to do this modeling. However, there is quite an easy way how to do this. So this is a problem in tricking the program to do something new.

9. Use the program to calculate potential of an electrochemical cell that contains a mixture of redox species. Choose at least 2 different pairs and different concentrations. Again, this is not the purpose of the program, but it will do it for you.

10. Using the movie feature, determine the different parameters that influence the thickness of the diffusion layer. Again, use several different conditions, unusual situations, etc.

11. Semilinear vs. finite open boundary and finite block boundary diffusion. Investigate this feature in the options menu. Explain the effects, document in words and using graphs.

12. Investigate the effect of a, the symmetry coefficient, on the voltammetric response.

13. Investigate the effect of return sweep potential (how close after the voltammetric peak the scan is reversed) on the readability. What is a safe value of potential reversal.

14. Demonstrate the effect of a real solvent/supporting electrolyte on voltammetric response. Again, a trick has to be done here, but it is possible.

15. Nondiffusion controlled process. For example evolution of oxygen on platinum (oxide formation ignored) is a process, that follows the Butler-Volmer equation and is not reversible in nature. Find a way how to use the program to give a good representation of the behavior.

CV  COMPUTER  SIMULATION SCHEDULE

8 students in this class, all have to pick a week when they will have exclusive use of the hardware key. (Since this page is accessible to the whole word, I am not listing the names.)

16 November Computer assignment is due

Possible topics for in-class presentation

16. Electrochemistry and environment

17. Micromachining and microfabrication (must have electrochemical aspects)

18. Electrochemical detection in HPLC

19. Spectroelectrochemistry

xx. Any other topic you wish to do.