Investigations of the Photochemical Properties of Oxide Surfaces and Composites

Gregory Rohrer, Materials Science & Engineering

A photochemical reaction is any chemical reaction initiated by light.  An everyday example is the yellowing of paper by sunlight. A more exciting example is when sunlight initiates the cleavage of water to produce hydrogen and oxygen.  Photochemical reactions on ceramic surfaces and sandwiches of dissimilar materials (heterostructures) are being studied with the goal of understanding the principles that might be used to create improved catalysts to make hydrogen fuel from sunlight.  It has been discovered that both layers of the heterostructure contribute to the overall reactivity of the material, even the buried substrate layer.  The top layer of the structure, in contact with water, catalyzes the photochemical reactions and the substrate layer below it determines where on the surface the reactions occur.  In this project, we will use atomic force microscopy to study how the locations of reduction and oxidation reactions on the surface correlate to the locations of ferroelectric domains in the substrate layer.