Michigan Tech Researchers Recognized For Work In Surface Science

 Chemists who discovered a new technique for measuring complex reaction processes at the interface of liquids, solids and gases have been awarded the 2023 Michigan Technological University Bhakta Ras Award.

The achievement of assistant professor Kathryn Perrine and her advisor, research assistant Chathura de Alwis, has opened up a new understanding of the redox reactions of iron and other earth-abundant metals and materials new insights into the chemical mechanism of These findings are important for current and future industrial and energy applications.

The Perrine research group uses surface analysis instruments, including polarization-modulated infrared reflectance absorption spectroscopy (PM-IRRAS), to measure surface chemistry, reveal physical and chemical phenomena, and address global challenges in energy and environmental science. The multidisciplinary team discovered fundamental knowledge to address corrosion, water quality, carbon capture and other key challenges, including researchers from chemistry, materials science, physics and engineering.

de Alwis was awarded a spring 2022 doctoral student fellowship and a 2021 Robert and Catherine Lane research fellowship, and completed a master’s and doctorate in physical chemistry at Michigan Technological University. He has a Ph.D. Ph.D. in Surface Science and Physical Chemistry in 2022, currently working as an Engineer in the LTD Etching Module at Intel Corporation.

Perrine and de Alwis were nominated for the award, with scientists highlighting the broad applicability of their work, the precision and potential of their measurement methods, as well as their detailed documentation and research excellence.

“This work provides a new understanding of iron corrosion, which is important in many industries and energy applications,” said Ashley R. Head, an associate scientist in Brookhaven National Laboratory’s Center for Functional Nanomaterials. ) wrote in her letter of support. “Their technique for studying the interface provides a higher degree of control over the thickness of the liquid and enables chemical reactions in air to better mimic chemical processes in real-world applications.”

In a separate letter of support, the nominee Hendrik Bluhm, head of the Department of Inorganic Chemistry at the Fritz-Haber Institute in Berlin, Germany, said the measurement method would be adopted by the global surface science and spectroscopy community. use.

The nominee, Petra Reinke, a professor in the Department of Materials Science and Engineering at the University of Virginia, stated in the nomination letter that the complexity of studying and interpreting surface reactions cannot be underestimated, and expressed appreciation for the duo’s systematic approach, productivity and academic excellence, which have been highlighted in numerous studies Proven. Track their steady progress and achievements in papers and presentations.

In a Michigan Tech News Q&A, Perrine and de Alwis reflect on their discovery and collaboration.

Q: What is your research content?

KP: We study the surface chemistry that leads to iron corrosion and carbon capture through mineral formation at the air-liquid-solid interface. We use our developed methods to reveal key mechanistic issues of pipeline corrosion, water quality and atmospheric processes, and surface-catalyzed reactions in complex interfaces.

CA: The liquid cell-based PM-IRRAS method was developed to simultaneously observe complex chemical reactions occurring at the air-liquid-solid interface under ambient conditions. A large number of reactions can be studied using this new method, such as interfacial metal corrosion, mineral formation, adsorption of molecules dissolved in the liquid phase, monolayer/multilayer adsorption, and adsorption of gas molecules at interfaces in different chemical environments. This method also facilitates the qualitative and quantitative investigation of the composition and kinetics of chemical products formed at the gas-liquid-solid interface.

Q: What are the applications of your research?

KP: My current group is studying the mechanisms of pipe corrosion due to interactions with water sanitizers, which affects our water distribution infrastructure. We are also working on measuring the mechanism of carbon capture at the liquid-solid interface. These are important in addressing the effects of climate change.

CA: This method can be used to study any complex reaction occurring at the gas-liquid-solid interface under ambient conditions. The reactions can be monolayer/multilayer adsorption, redox reactions, inorganic/organic reactions, mineral formation, and adsorption of atmospheric or controlled ambient gases at gas-liquid-solid interfaces. Understanding the fundamental chemistry of such interfaces helps broaden our understanding of the chemistry of macroscopic systems, such as the behavior of metal corrosion, mineral formation, and water pollutants.

Q: You gained an important insight during your presentation at the Environmental Science Outreach Water Festival that moved your research forward. Tell me more about the realization of that moment.

KP: With the help of Joan Schumaker-Chadde, our group developed and provided a simple corrosion experiment as part of an environmental science outreach program for grades K-12. During an outreach demonstration, I left a sample of iron soaked in a dilute vinegar and salt solution to demonstrate corrosion to students. There, my graduate students and I presented a demonstration of copper, zinc, and steel corrosion as a model for water pipelines, which can help students understand water quality and the impact of the Flint water crisis. By the end of the demonstration, the iron sample had developed a red rust band at the air-solution interface. At that moment, I realized that there was some interesting chemistry in the interfacial region. The color of the rings left behind was measured using PM-IRRAS, a reflective surface analysis technique, leading to the idea that an ultra-thin layer of liquid is needed to see changes on a solid surface. I rushed back to the lab after the demo and tested the reflexes with a laser pointer. We later reproduced the results in the laboratory with a stable setup, allowing us to observe iron surface oxidation in real time.

Q: What existing tools have you used? What tools need to be invented?

KP: PM-IRRAS is a vibrational spectroscopy technique known since the 1990s to detect liquid/solid and gas/solid interfaces. Other related techniques also have limitations. We want to be able to instrument both interfaces at the same time. To test whether we can see chemical reactions through layers of liquids, we first needed to establish a method using well-known chemical reactions as a proof of concept. Later, once we were able to reproduce the results, we needed a model to relate the signal to the liquid layer thickness, where . Dr Timothy Leftwich (Research Assistant Professor) from the Department of Materials Science and Engineering helped by developing models.

CA: For decades, conventional PM-IRRAS has been used as a surface-sensitive infrared spectroscopy technique to detect surface adsorption/desorption reactions occurring on reflective surfaces such as Au metal (gold). In our study, we modified and developed this PM-IRRAS technique using a custom-made liquid cell so that we can simultaneously detect the gas-liquid-solid interface and monitor complex chemical reactions occurring in ambient or controlled environments.