Anne asked the students in her junior/senior inorganic course to develop their own literature discussion learning objects and lead the rest of the class in a discussion of their article. Each student chose one article from a list of suggestions provided. Student Hayley Johnston chose this article describing a Mn-containing catalyst for carbon dioxide reduction (Jonathan M. Smieja, Matthew D. Sampson, Kyle A. Grice, Eric E. Benson, Jesse D. Froehlich, and Clifford P. Kubiak, “Manganese as a Substitute for Rhenium in CO2 Reduction Catalysts: The Importance of Acids” Inorganic Chemistry 2013, 52, 2484-2491. DOI: 10.1021/ic302391u). The article describes the development of a Mn-based homogeneous catalyst for electrocatalytic CO2 reduction. Hayley met with Anne for an hour to discuss the article, then generated a list of questions drawn from the article's content. Using Hayley’s original set of questions as a starting point, Anne and Kyle developed this literature discussion, which is suitable for use in inorganic chemistry courses.
After reading and discussing this paper, a student will be able to:
- Describe the value of CO2 reduction catalysts
- Outline the structure of the catalyst and identify the path electrons take throughout the catalytic cycle
- Compare and contrast the Mn-based and Re-based catalysts in terms of their CO2 reduction efficiency
The learning object we've developed contains fifteen questions that cover most of the article's content in great depth. It's likely too long for an individual assignment, depending on the students' backgrounds. We encourage instructors to pick and choose from among the questions.
Before discussing this article, students should be familiar with the concepts of renewable fuels/artificial photosynthesis and maybe also the Keeling curve demonstrating the sharp increase in atmospheric carbon dioxide over the past two hundred years.
Students may not know that CO, carbon monoxide, is very useful. They will likely be most familiar with its dangers, not its importance in industrial chemistry. Instructors could discuss the uses of CO: synthesis of methanol (nearly all industrial methanol comes from CO), synthesis of acetic acid (nearly all of the acetic acid comes from CO and methanol), hydroformylation, and Fischer-Tropsch chemistry (which could be used to make gasoline/diesel – South Africa has used this technology for some time).
A discussion of cyclic voltammetry would also be useful, including discussing the role of ferrocene as an internal reference. We have referenced the “five slides about” LO Cyclic Voltammetry created by Prof. Chip Nataro as a related activity.
In terms of placing this manuscript in context, previous studies included rhenium complexes, which work without added proton sources but are much improved in the presence of proton sources. The seminal work on rhenium complexes was performed by Jean-Marie Lehn (of supramolecular Nobel Prize fame) in the 1980s.
A comprehensive review of the history of these Re and Mn complexes from their discovery up to early 2013 can be found in “Chapter Five – Recent Studies of Rhenium and Manganese Bipyridine Carbonyl Catalysts for the Electrochemical Reduction of CO2” Kyle A. Grice and Clifford P. Kubiak Advances in Inorganic Chemistry, 2014, 66, 163-188 (see web resources below).
Several more recent papers have also been published on the Re and Mn systems from the Kubiak group and other groups since early 2013, including mechanistic studies of the Re and Mn systems using a variety of methods. A forward search of the Mn manuscript by Smieja et al. can be used to find these articles.
For more detailed information about IR-SEC, see this reference and references therein: Charles W. Machan, Matthew D. Sampson, Steven A. Chabolla, Tram Dang, and Clifford P. Kubiak Organometallics, 2014, ASAP (see web resources below).
Anne’s student led a 20-minute class discussion of this article in the spring of 2014. The other students in the class were asked to post two questions about the article to moodle before the class meeting, but they were not asked to complete the literature discussion questions due to assignment overload at the end of the semester.
Students’ questions varied from the very specific to the very general. One wanted to know what the parameter “tau” referred to, and another was confused about the concept of overpotential. Many students weren’t sure why making carbon monoxide would be a good idea, as they see it as poisonous. One student wanted to know if these catalysts could ever be used in ambient conditions. Students were curious to know more about the catalytic mechanism.