Compelling research is happening on campus with the use of the X-ray photoelectron spectroscopy instrument (PHI 5800 XPS, known as XPS). Kathryn Perrine, assistant professor of chemistry, uses the XPS and other techniques (i.e., infrared spectroscopy) to analyze the surface of materials and how chemicals react on the surface. According to Perrine, examining a material’s surface with the XPS helps researchers and students design new technologies like batteries, biomaterials, and electronic devices. The XPS was donated to Michigan Tech by the Army Research Laboratories with help from the Department of Chemistry in 2016. The XPS is housed in the Applied Chemical and Morphological Analysis Laboratory and run by Perrine and Timothy Leftwich, research professor in the materials science and engineering department, both surface scientists.
Currently, Perrine and her research team are studying dichlorination and oxidation reactions on iron surfaces for understanding them as heterogeneous catalysts and their role in water quality. Specifically, Perrine and her team use the XPS to, “understand the oxidation state of the iron, what absorbs to the surface, and what that chemical is,” Perrine explains. “Different types of reactions can happen on various sites (i.e., pure iron surfaces or oxidized surfaces). We are working to understand reactions like the liquid-solid interface and how to connect reactions to reactions at the gas-solid interface. At the gas-solid interface, a lot of our research occurs in a vacuum, so we can control water vapor and other chemicals that have a gas-based pressure. Once the chemicals interact with the surface, we can measure under controlled conditions how that reaction occurs. The condensed space offers a more realistic perspective, in terms of aqueous media, how reactions happen in an aqueous environment, and the role of water and oxygen in those reactions.”
Perrine also teaches a surface analysis class in which graduate students use the XPS to analyze and interpret data. “I don’t just teach about XPS analysis, I teach about all surface processes,” she says. Studying the surface helps researchers design materials for potential technologies. “We can analyze elemental composition of coatings, probe film layers using depth profile analysis, and observe surface contamination and functionalization of surfaces. This allows us to design better materials and develop new technologies just by understanding on the molecular level what happened to the surface of a material.” Ultimately, XPS is a powerful surface analysis instrument that enables the Michigan Tech community to conduct high-quality research and develop new materials and technologies.