National Synchrotron Light Source Seminar

The use of metal oxide films, nanomaterials, and heterostructures in photoanodes enabling the solar-driven oxidation of water and generation of hydrogen fuel (solar water splitting) is examined. A range of transition- and post-transition-metal oxide material systems and nanoscale architectures is discussed in order to provide an overview of the field and recent results from the authors’ laboratories. Electrode structures examined include thin films, nanorod arrays, and heterostructures comprised of oxides such as -Fe2O3, ZnO, TiO2, and SnO2. The electronic structures of key oxide-oxide interfaces, relevant to the operation of efficient photoanodes, are examined using soft X-ray spectroscopy. These studies indicate that the interfacial regions of electrodes possess distinct electronic structures, which deviate in terms of orbital character and occupancy from those of their constituent bulk oxides. These observations can inform methodology to address certain operational deficiencies associated with the use of metal oxides for solar energy conversion applications.