7 Jan 2014

Solar-Powered Oxidation of Water

Literature Discussion

Submitted by Anne Bentley, Lewis & Clark College
Categories
Description: 

Students in a half-credit nanomaterials chemistry course read an article describing the electrochemical deposition of BiVO4 (Kyoung-Shin Choi and Jason A. Seabold, “Efficient and Stable Photo-Oxidation of Water by a Bismuth Vanadate Photoanode Coupled with an Iron Oxyhydroxide Oxygen Evolution Catalyst” J. Am. Chem. Soc. 2012, 134, 2186-2192.  DOI: 10.1021/ja209001d).  The oxygen evolution driven by the bismuth vanadate was significantly enhanced by the addition of an iron oxide catalyst to the material’s surface.  This article is fairly easy to understand and can be used as an introduction to electrodeposition and photoelectrochemical cells.

AttachmentSize
Microsoft Office document icon BiVO4_photoanode.doc36.5 KB
Learning Goals: 

After reading and discussing this paper, a student will be able to:

  • Compare and contrast the experimental techniques used to gather the data presented in the article in terms of the type of information that can be obtained from each.
  • Describe the significance of this research in comparison to other types of materials used in the photo-oxidation of water
  • Describe the importance of solution pH in determining the feasibility of electrodepositing the BiVO4 material.
  • Outline the synthetic steps taken to achieve the final BiVO4 material and the FeOOH catalyst.
Implementation Notes: 

I used this assignment in my half-credit nanomaterials chemistry course in the fall of 2013.  The enrollment was seventeen students, including 14 chem majors, 2 biochem majors, and 1 physics major.  There were 4 seniors, 11 juniors, and 2 sophomores in the course.  Throughout the course, I assigned journal articles to read after we had done some introduction of the topic in lecture, but the assignments did not necessarily fall at the end of the topic.  Students brought their completed questions to lecture, handed them in, and then we discussed the article in detail as a class.  In this case, the students had already been introduced to solid state band structure using the “To Conduct or Not to Conduct” learning object in the previous week, when I had also introduced photovoltaics and the NREL solar efficiency graph.  In the lecture before this assignment was due, I explained that semiconductors can also be used to drive chemical reactions in photoelectrochemical cells.  I used TiO2 as an example of a photoanode and outlined the water splitting reaction.  We compared semiconductor band gap positions and water splitting redox potential positions.  I explained that even if these energies are aligned properly, a catalyst is often required. 

On the day the assignment was due, we reviewed the questions.  I created a chart on the board comparing the strengths and weaknesses of the different analysis techniques used in the article.  The students don’t have their assignments in front of them for this discussion, but they do hold onto their copy of the article, and their answers seem to be fresh in their minds.

Time Required: 
45 minutes
Evaluation
Evaluation Methods: 

I used this assignment in my half-credit nanomaterials chemistry course in the fall of 2013.  I graded the assignments on a 30-point scale, with all questions worth three points except for #1 (worth 7) and #4 (worth 8).

Evaluation Results: 

The average score on this assignment was 23.8 out of 30.  On the whole, the students found the article to be one of the most accessible of all the articles we read during the semester.

Creative Commons License: 
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