(204b) Developing New Wide Band Gap Semiconductors for Water Photolysis

We are developing dye-sensitized metal oxides for photochemical energy conversion. We would like to understand the basic structural and chemical characteristics that control electron conduction and reactivity in particle-based porous photocatalysts. These issues are fundamental to the design of efficient high surface area heterogeneous photocatalysts. With the information gained from these experiments, we can increase the yields of sun driven direct water photolysis to provide a cost-effective source of hydrogen gas. We have synthesized highly porous metal oxides made of wide bandgap semiconductors. These new materials work well as electron-hole producing catalysts under UV light. However, we are interested in using them in conjunction with visible light sensitizers to develop visible light photocatalysts for a direct water splitting process. Here we have tested the un-sensitized catalyst for its ability to reduce gold and platinum ions in water to their metallic state. The metals are deposited on the surface of the catalyst at locations that are most catalytically active. This provides some insight on the best catalyst structure.