In the two years since this article was published, it has jump-started a large amount of research in the area of cobalt-based catalysts for solar water splitting. The paper describes the electrochemical synthesis and oxygen-evolution capabilities of a Co-phosphate catalyst under very mild conditions. The paper can stimulate discussion of many topics found in the inorganic curriculum, including electrochemistry, semiconductor chemistry, transition metal ion complex kinetic trends, and solid state and electrochemical characterization techniques.
After reading and discussing this paper, a student should be able to:
• explain, using concepts of electrochemical potential and band theory, how semiconductors can be used to generate hydrogen fuel from sunlight and water.
• describe the desirable characteristics of an oxygen-evolving catalyst and explain why this catalyst is a marked improvement over existing materials.
• follow the oxidation/reduction cycle of the cobalt ion as it goes from solution to the catalyst compound and then back into solution.
• characterize the cobalt ion as inert or labile based on its d electron count and relate the kinetic trends to the self-repair mechanism proposed in the article.
This learning object was developed as one of five journal article discussions included in a small (5 student) senior-level inorganic course in the spring of 2010. This course is the only inorganic course (aside from a separate inorganic laboratory) offered in our curriculum. The ten questions included here are not nearly comprehensive and can be considered a jumping-off point for further development. In particular, the last question could be extended to ask students to read and briefly present the results of one of the articles that has referenced this paper. Research in this field has been advancing rapidly.
The literature discussions were interspersed throughout the semester. In each case, students read the article and answered the questions before coming to class, then presented select questions in teams of two or three to the rest of the group.
The students’ written answers to the questions and presentations of the questions were graded.
Students answered the questions well. If anything, this series of questions may be too “easy” for senior-level students. I hope to increase the level of difficulty in the future.