Water splitting photocatalysis with first row transition metal oxides

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With this award from the Chemical Catalysis Program of the Division of Chemistry, Professor Frank E. Osterloh from the University of California at Davis will attempt to convert inexpensive and stable first row transition metal oxides into effective photocatalysts for splitting water into oxygen and hydrogen fuel. Even though many known materials absorb visible light strongly, they are not being utilized for photochemical water splitting because photochemical charge carriers are short lived, charge transport is slow, and because of large overpotentials for water reduction or oxidation. In this research these problems will be addressed by nanoscaling the materials and by modifying the surfaces of the particles using chemical processes that will improve reactivity. Advanced measurements on the nano-metal oxides will be conducted to obtain new insight into the relationship between particle size, electronic properties, and photocatalytic activity. The water splitting reaction has long been considered as a possible method to generate fuel from solar energy. Here, light is used to excite a material to produce a photovoltage. That voltage can then be used to electrolyze (cleave) water into hydrogen and oxygen. Hydrogen is an energy-rich molecule that can serve as a versatile fuel for transportation, or to generate electricity and other high value chemicals. Because sunlight is used as energy source for making the hydrogen, no fossil fuels are used up and no carbon dioxide is produced that would contribute to climate change. Today, solar water splitting is limited by the lack of materials that have the desired reactivity and absorb visible light, and that are chemically stable, abundant, and cheap enough for large scale application of this technology. This project will attempt to develop transition metal oxides as catalysts for the process. These oxides have been shown to combine several promising properties, and they are cheap and abundant. Graduate and undergraduate students will be involved in all aspects of the project. The students will receive training in solar energy conversion and materials science. Chemical demonstrations will also be developed to educate the public about the importance of solar energy conversion.