Metal Oxides for the Generation of Solar Hydrogen 

Hematite (a-Fe₂O₃) is a promising material for sustainable generation of H₂ due to its low cost, widespread availability, chemical stability, and ability to absorb a significant fraction of visible light. However numerous challenges remain in order for this material to approach its theoretical potential of 15% solar to hydrogen efficiency. The two most important metrics for photocurrent are its onset potential and the current plateau. The former is limited by the kinetics of the oxygen evolution reaction, while the latter is a measure of the fraction of photo-generated carriers that can be extracted to perform water splitting. In this project we are addressing these issues by controlling nanostrucure, doping, and interface engineering. Nanowire arrays of hematite are synthesized from aqueous solution and subsequent calcination. This scalable approach produces robust, uniform films using low cost precursors. Through appropriate control of process conditions we have achieved significant improvements in photocurrent response. Through further optimization of microstructure and through the integration of electrocatalysts we hope to further enhance performance. Dr. Rachel Moorish is leading our efforts in this area with assistance from undergraduate Alex Sale.

Support for this project is being provided by Colorado Renewable Energy Collaboratory through its Center for Revolutionary Solar Photoconversion (CRSP) and the REMRSEC REU site.