The Division of Chemistry supports Rachel Morrish of the Colorado School of Mines as an American Competitiveness in Chemistry Fellow. Dr. Morrish will synthesize and study the behavior of photoanodes made from nanomaterials created from earth-abundant materials (Fe/O/S). She will collaborate with scientists at the National Renewable Energy Laboratory to characterize these materials and incorporate photoanodes into tandem cells. For her plan for broadening participation, the PI will develop a hands-on solar energy demonstration for use in outreach activities and public school teacher-training. These activities will reach a large number of underrepresented students in the Colorado area.
Research like that of Dr. Morrish is aimed at developing new kinds of materials for the generation of fuel from solar energy. These materials may help in developing solutions for sustainable energy production. The particular materials that Dr. Morrish is developing are "green" in that they use earth-abundant elements that have low toxicity. The efforts at broadening participation being pursued by Dr. Morrish are aimed at giving underrepresented students in the mountain states hands-on activities in important areas of science related to sustainability.
In this project, a new approach for preparation of solar absorbing pyrite (FeS2) thin films was developed. Pyrite is a non-toxic, earth abundant material with desirable characteristics for application as an absorber including a modest band gap of 1.0 eV and a large optical absorption coefficient (>105 cm-1). When placed in water and exposed to sunlight, pyrite can help generate H2 and O2 gas. This H2 can be easily stored and transported for application as an on-demand, clean chemical fuel. Intellectual Merit With this research support, an innovative plasma-assisted approach for preparing pyrite (FeS2) thin film solar absorbers was developed. Pyrite was produced by introducing sulfur into the more easily obtained metal oxide, Fe2O3 by way of a H2S plasma. The transformation from oxide to sulfide occurred through a direct solid-state reaction that bypassed contaminate sulfur deficient phases. Application of a plasma reduced the time and temperature needed for conversion and also produced higher material quality than thermal approaches. The band gap of the prepared layer could be varied between that of Fe2O3 (2.2 ev) and FeS2 (1.0 eV) by simply changing the amount of sulfur. Fully converted FeS2 films were photoactive and also catalytic toward the iodine reduction reaction. This plasma-assisted approach was not limited to iron materials; preparation of WS2 was also demonstrated. The WS2 films were found to be stable catalyst for the hydrogen evolution reaction and could be a possible replacement for platinum. In total the project produced 2 peer-reviewed journal articles, 5 conference presentations (2 by an undergraduate student), and 1 patent application. Broader Impacts One aim of this project was to broaden participation in chemical sciences. This was accomplished in two ways: 1) National Chemistry Week (NCW) Outreach at the Denver Museum of Nature and Science Over 400 children were reached each year Hands-on activities included shining a penny and powering a fan with a light bulb 2) Incorporation of Research into Undergraduate Education Added a 1-week electrochemistry supplement to the junior-level thermodynamics course Partially supported two undergraduates who appeared as coauthors on publications
