Solar driven water splitting for large-scale hydrogen fuel production from semiconductor photo-electrodes has the potential to provide energy on large scale from renewable, sustainable sources. My group's research focuses on generating ternary oxide thin film photoelectrodes prepared by low-temperature, solution-based processes for the kinetically more demanding oxygen-evolution reaction. The workhorse material in our group is CuWO4, which we have synthesized by several routes: electrochemical deposition, sol-gel processing, and spray pyrolysis. These methods afford highly reproducible, chemically pure, and robust electrodes on transparent conducting substrates. CuWO4 is an n-type semiconductor with a band-gap energy of ~2.4 eV. CuWO4 thin films photooxidize water with simulated solar radiation with a nearly quantitative Faradaic efficiency for O2 evolution in borate-buffered saline solution. Most important, they are chemically stable against photocorrosion when illuminated with visible light at neutral pH, and they are selective for water oxidation in the presence of the Cl�or HSO4�, common anions in aqueous electrolytes. These characteristics are a significant improvement to the more commonly studied binary phase, WO3. Moreover, we can anchor derivatives of known molecular water oxidation catalyst complexes such as Fe(tebppmcn)Cl2 to the surface of WO3 to improve its efficiency for selective photoelectrochemical water oxidation.

Designing chemically robust solar-responsive metal oxides for photoelectrochemical water oxidation

248th National Meeting (2014)

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