Pacific Northwest National Laboratory
Oxides in Action: Atomic-scale behavior of oxide surfaces under working conditions
Location: EB1 Room 1011
Friday, February 19th 2016 - 11:00 am
As global energy demands grow, so do the applications of oxide materials as catalysts for chemical reactions and photo-absorbers for solar water splitting. The atomic-scale structure of an oxide surface critically affects its desirable chemical behavior but also determines undesirable consequences such as degradation. My research explores the atomic-scale interactions between oxide surfaces and real-world environments. Using X-rays, which penetrate through gases or liquids, we can directly probe the buried oxide-fluid interface. The scattering or absorption of X-rays at the interface is analyzed to determine its structure. Scanning probe microscopy gives complementary real-space pictures of interfacial phenomena at the nanoscale. As an example, I will discuss how oxide surfaces provide a stage upon which to study synergies between catalyst components, such as the interaction between V and W oxides which improves the catalytic removal of harmful nitric oxides. I will also show how electrochemically poised iron oxide surfaces undergo subtle structural changes leading up to reductive dissolution, with implications for natural iron cycling as well as the stability of photo-absorber materials for solar water splitting. These cases exemplify the capability of state-of-the-art interface science to reveal the structure and function of oxide interfaces.