Electrochemistry

9 Oct 2019

2019 Nobel Prize - Li-ion battery LOs

Submitted by Barbara Reisner, James Madison University

Congratulations to the 2019 recipients of the Nobel Prize - John B. Goodenough, M. Stan Whittingham and Akira Yoshino. It's a well deserved honor!

There are several LOs on VIPEr that talk about lithium ion batteries and related systems. The 2019 Nobel is a great opportunity to include something about these batteries in your class.

I hope to see more LOs in the coming weeks so we can bring this chemistry into our classrooms!

Prerequisites: 
Corequisites: 
25 Jul 2019

1FLO: One Figure Learning Objects

Submitted by Chip Nataro, Lafayette College
Corequisites: 
9 Jun 2019

1FLO: PCET and Pourbaix

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

I graded each student’s problems as I would any other homework assignment, and they averaged about 80% on that part of the assignment. The other half of the total points for the assignment came from in-class participation.

Evaluation Results: 

We had a rich conversation about this article in class; it was probably one of the most interesting literature discussion conversations I’ve had. Although this was the only introduction to Pourbaix diagrams in the course, 12 of 15 students correctly interpreted a “standard” Pourbaix diagram on a course assessment.

 

Description: 

This set of questions is based on a single figure from Rountree et al. Inorg. Chem. 2019, 58, 6647. In this article (“Decoding Proton-Coupled Electron Transfer with Potential-pKa Diagrams”), Jillian Dempsey’s group from the University of North Carolina examined the mechanism by which a nickel-containing catalyst brings about the reduction of H+ to form H2 in non-aqueous solvent. Figure 3 in the article presents an excellent introduction to the use of Pourbaix diagrams and cyclic voltammetry to determine the mechanism of a proton-coupled electron transfer reaction central to the production of hydrogen by a nickel-containing catalyst.

Corequisites: 
Course Level: 
Learning Goals: 

Students should be able to:

-  identify atoms in a multidentate ligand that can coordinate to a metal as a Lewis base

-  outline the difference between hydride addition to a metal and protonation of a ligand in terms of changes to the overall charge of the complex

-  analyze a Pourbaix diagram to predict the redox potential and pKa of a species

Subdiscipline: 
Implementation Notes: 

I have discussed the challenge of integrating literature discussions into my inorganic course in a BITeS post and the VIPEr forums. Each spring I try something a little different. This year I used three articles from the literature to frame our review of course material at the end of the semester, with each literature discussion occupying a one-hour class meeting.

In each case, the students completed problems before coming to class. While these problems were based on the journal articles, they did not require the students to read / consult the journal articles in order to complete the assignment. The students brought an electronic or paper copy of the article to class. I usually put students in groups (approximately 3 per group) and gave each group new questions to work on, which did draw from the article. After some time working in groups, each group presented their material to the rest of the class.

In implementing this particular literature discussion, I didn’t have any further questions for them.  I walked through some of the other figures from the article (especially Figure 1).  We discussed the authors’ use of color in creating Figure 3. We also reviewed the significance of horizontal vs vertical vs diagonal lines. Because I had not covered Pourbaix diagrams in the course, the activity was a good introduction to the concept.

Because these problems don’t require consultation with the article, they are suitable to use on an exam.

Time Required: 
varies
8 Jun 2019

VIPEr Fellows 2019 Workshop Favorites

Submitted by Barbara Reisner, James Madison University

During our first fellows workshop, the first cohort of VIPEr fellows pulled together learning objects that they've used and liked or want to try the next time they teach their inorganic courses.

6 Jun 2019
Evaluation Methods: 

The guided reading questions may be graded using the answer key. 

Evaluation Results: 

These questions have not yet been assigned to students.

Description: 

Guided reading and in-class discussion questions for "High-Spin Square-Planar Co(II) and Fe(II) Complexes and Reasons for Their Electronic Structure."

Course Level: 
Learning Goals: 

1.  Bring together ligand field theory and symmetry.

  1. Students should be able to identify symmetry of novel molecules in the literature.

  2. Students should be able to explain d-orbital ordering in a coordination complex using ligand field theory.

  3. Students should be able to identify donor/acceptor properties of previously unseen ligands.

  4. Students should be able to apply your knowledge of electronic transitions to the primary literature.

  5. Students should be able to become more familiar with 4-coordinate geometries.

  6. Students should be able to predict magnetic moments of high-spin and low-spin square-planar complexes.

  7. Students should be able to identify properties of ligands that favor formation of the highly unusual high-spin square planar complexes.

2.  Students should comfortable with reading and understanding primary literature.


 

Related activities: 
Implementation Notes: 

You do not have to assign all of the guided reading questions at once.  You may consider assigning questions as they pertain to where you are in your inorganic chemistry class.

Time Required: 
this has not been used yet for in-class discussion.
7 Aug 2017

Redox Chemistry of a Potential Solid State Battery Cathode – Discuss!

Submitted by Sabrina G. Sobel, Hofstra University
Evaluation Methods: 

Different models for class implementation:

1. Professor-led student discussion; monitor quantity and quality of individual student input.

2. Student-led presentation and discussion (pairs work well); grading of presentation and quality of question answers.

3. Student written report answering Literature Discussion questions.

Evaluation Results: 

We have not implemented this Literature Discussion in class yet.

Description: 

Lithium battery technology is an evolving field as commercial requirements for storage and use of energy demand smaller, safer, more efficient and longer-lasting batteries. Copper ferrite, CuFe2O4, is a promising candidate for application as a high energy electrode material in lithium based batteries. Mechanistic insight on the electrochemical reduction and oxidation processes was gained through the first X-ray absorption spectroscopic study of lithiation and delithiation of CuFe2O4. The results provide new mechanistic insight regarding the evolution of the local coordination environments at the iron and copper centers upon discharging and charging. Students learn about normal and inverse spinel structures, solid cathode electrochemical processes and the use of X-ray absorption spectroscopy to figure out local structure, oxidation state and coordination environment.

Corequisites: 
Course Level: 
Learning Goals: 

1. Students should become familiar with the parts and charging/discharging of a solid-state lithium battery, and relate to introductory discussions of redox chemistry.

2. Student should learn about spinel and inverse spinel structures, and be able to relate to cubic unit cell types presented in General Chemistry.

3. Students should learn how X-ray absorption spectroscopy can be used to evaluate oxidation state and local coordination environment in a solid.

Implementation Notes: 

The powerpoint presentation about X-ray absorption spectroscopy can be used to provide background for the analytical techniques used in this research. The classic spinel structure should be discussed in class. Otherwise, this can be implemented like any other Literature Discussion.

Time Required: 
two half-class periods; one for background, and one for discussion
5 May 2017

SOP4CV - A Web Resource for Cyclic Voltammetry Information

Submitted by Gerard Rowe, University of South Carolina Aiken
Description: 

http://sop4cv.com/

This is a great website created by Dr. Daniel Graham (who has the distinction of publishing a paper featured on TOC ROFL) to give anyone a working understanding of cyclic voltammetry techniques, their physical background, and the interpretation of their results.  

Prerequisites: 
Corequisites: 
Subdiscipline: 
Learning Goals: 

Students will gain experience interpreting the basic features of cyclic voltammograms, including: half-potential, electrochemical reversibility, chemical reversibility, and scan rate dependence

Students will learn the physical origins of the "duck" shape of a reversible CV using the Nernst equation and diffusion concepts

Students will learn what analytical methods are available using CV

Implementation Notes: 

None yet.  I'm considering creating an activity using the information in this website, but for now I just wanted to share this resource.

10 Apr 2017

Redox Chemistry and Modern Battery Technology

Submitted by Zachary Tonzetich, University of Texas at San Antonio
Evaluation Methods: 

I do not grade this activity, but if I did, I would look for class participation in the discussion or assign several of the questions to be turned in at a later date.

Evaluation Results: 

My impression of this activity is that it really helps students see the value of redox chemistry. In my experience, the aspects of redox chemistry we teach students (balancing equations, calculating cell potentials, etc.) seem both difficult and esoteric. This activity reinforces these concepts while demonstrating their importance to modern life. One of the biggest realizations the students come to is the relationship between cell voltage and the mass of the materials involved in the redox reaction.

Description: 

This In-Class Activity is a series of instructor-guided discussion questions that explore lithium-ion batteries through the lens of simple redox chemistry. I use this exercise as a review activity in my Descriptive Inorganic Chemistry course to help prepare for examinations. However, my primary purpose with this exercise is to impress upon students how basic concepts in redox chemistry and solid-state structure are directly relevant to technologies they use everyday. I do not focus too heavily on the design or operation of the batteries themselves, as other exercises published on VIPEr already do a very good job of that. My intention is to demonstrate how a basic knowledge of redox chemistry is the first step in understanding seemingly complex technologies.

Learning Goals: 

The primary goal of this In-Class Activity is for students to solidify their understanding of redox reactions, cell voltages and the relationship between electrical energy and potential. The exercise is also designed to show students how these considerations are part of the design of modern batteries. A secondary aspect of the activity explores the solid-state structure of metal-oxides and how these materials are important to the operation of the battery. At the conclusion of the activity, the student should be familiar enough with calculaing cell voltages and free energy changes that they can critically evaluate the components of a standard battery.

Equipment needs: 

None.

Course Level: 
Prerequisites: 
Corequisites: 
Implementation Notes: 

I display the pdf file on screen and use the white board to work out simple arithmetic aspects of the exercise, while soliciting responses from the class.

Time Required: 
45 minutes
27 Mar 2017

Nanomaterials for Carbon Dioxide Reduction

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

The problems presented here represented half the points on the final exam – I have included point totals to give an idea of the weight assigned to each problem.

Evaluation Results: 

Twelve students were enrolled in my course in the fall 2016. The average overall score for these problems was 78%.

For problem 1b, I calculated the oxidation numbers using the familiar general chemistry method of assigning oxygen as –2 and hydrogen as +1. Students recently coming through organic may have some other way to do it, and you may need to provide directions for your students about your preferred method.  I think I could have worded part (c) better to try to emphasize the redox processes involved. I wanted them to think of combustion, but I think they needed to be specifically prompted, such as "Give an example of the combustion processes that generate CO2 and trace the oxidation state of carbon through the reaction." Overall my students scored 86% on problem 1.

The second problem (about another method that could be used to measure d-spacing) was fairly hit or miss.  Five students got full credit, six students got 3 points, and one got zero. Eleven out of twelve did answer part (a) correctly.  I realized as I made this LO that the article says the carbon-based material doesn’t diffract X-rays, but doesn’t actually directly explain whether or not the Cu nanoparticles diffracted X-rays, so you may need to adjust the question to be technically accurate.

Question three (re: surfactants in nanoparticle synthesis) referred back to knowledge from earlier in the course. The overall score was 61%.

Question 4 (define and describe electrodes) was fairly straightforward, and students scored 85%.

Question 5 caused some confusion, as some students missed that I was looking for “carbon-containing” products only. I didn’t count off for that mistake, but it made the problem harder for students who included hydrogen in each box.  Overall, students did very well on this problem (89% correct).

Question 6 – again, not too much trouble here (84% correct).

Question 7 – I was surprised that students didn’t do better on this question, as I thought that water reduction was mentioned often in the article.  Only three (of 12) students scored 5 points on this problem, and the average score was 53%.  This was probably my favorite question, as it foreshadows electrochemistry topics I cover in my inorganic course.

Description: 

This literature discussion is based on an article describing the use of copper nanoparticles on an N-doped textured graphene material to carry out the highly selective reduction of CO2 to ethanol (Yang Song et al., “High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle / N-Doped Graphene Electrode” ChemistrySelect 2016, 1, 6055-6061.  DOI: 10.1002/slct.201601169). The article provides a good introduction to the concepts of electrochemical reduction, selectivity and recycling of fossil fuels. The literature discussion assignment shared here was used as half of the final exam in a half-credit nanomaterials chemistry course, but could be adapted for use as a take-home or in-class assignment.

Corequisites: 
Course Level: 
Learning Goals: 

After reading this paper and working through the problems, a student will be able to:

  • assign oxidation states to carbon and trace the oxidation and reduction of carbon through fossil fuel combustion and CO2 conversion
  • describe the role of control experiments in studying the CO2 conversion presented in the article
  • define the word “selective” in the context of this research
  • use the proposed mechanism to explain why the electrode studied produces ethanol in such a high proportion
  • identify the primary reaction competing with CO2 reduction for available electrons
Implementation Notes: 

These questions comprised half of the final exam for my half-credit nanomaterials chemistry course in the fall of 2016.  I gave the article to the students one week ahead of time. They were encouraged to read the article, make any small notes they liked, and meet with me in office hours with questions. At the final exam they were allowed to use their copy of the article, but they were also required to hand in their copy with their exam so that I could make sure they hadn't written lots of extraneous information on the exam copy.

The nanomaterials course features near-weekly homework assignments centered around articles from the literature. Because I used this article at the end of the course, students were already familiar with nanomaterials synthesis and characterization techniques. Thus, some of the questions I asked relied on previous knowledge. 

Please feel free to adapt these questions and add some of your own. Leave comments describing any new questions you’ve added.

Time Required: 
one hour
3 Mar 2017

In-class peer review

Submitted by S. Chantal E. Stieber, Cal Poly Pomona
Evaluation Methods: 

Student participation was evaluated during the in-class portion based on the questions students asked. 

The formal peer review homework was evaluated based on completion, level of thought and thoroughness.

Evaluation Results: 

Overall, students were very interested in this topic and had not formally learned about the process before. There was a very lively discussion and a lot of questions were asked. All students received full credit for participation. 

Similarly, once students received their classmate's paper for peer review, they took the process very seriously and carefully went through the paper and answered the worksheet questions. 

I was very impressed by the high quality of the formal peer reviews that were turned in as homework. Students clearly spent a lot of time to carefully think about the paper and craft a reasonable response. Most students received full-credit. 

Description: 

This activity includes questions for students to answer to help guide them through the process of peer review. It was designed to assist students in writing peer reviews for research reports written by their classmates, but could be applied to literature articles as well.

Corequisites: 
Prerequisites: 
Learning Goals: 

A student will be able to:

-Explain how the peer-review process works

-Critically read through a research article

-Carefully review a research article

-Write a professional peer review

Implementation Notes: 

An overview of peer review was given with three powerpoint slides. Students then worked through a modified Q&A of the peer review module "Peer Review - How does it work?" posted by Michael Norris on VIPEr. This provided students with an example of real reviews, along with the resulting article revisions. 

The current worksheet was then passed out to students along with a research report written by one of their classmates (I assigned these and removed names). In class, students answered the questions on the worksheet and were able to ask questions of the editor (the instructor in this case). Following the in-class peer review, students had to write a formal peer review, which was turned in as homework. 

The peer review was a final component of a research report that students had been working on throughout the course. The final report was turned in after students had received the review comments back from their peers. The grade of the final report took into consideration whether or not students had made modifications based on comments by their peer reviewer.

 
Time Required: 
60 min

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