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Center for Nonlinear Studies |
Understanding corrosion phenomena through thermodynamic interaction between the metal surface and environmental gasses is important to design effective solutions to tackle corrosion. Upon contact with a metal surface, these atmospheric molecules undergo chemical and physical changes including dissociation and charge exchange. As a result, the surface potential changes, and interferes with the general properties of the surfaces. In my presentation I will discuss about the influence of O2, N2, and H2 on titanium (Ti) surface that was derived using the first-principles thermodynamics [1]. The temperature and pressure diagram of chemical potentials between oxygen, nitrogen, and hydrogen gas suggested that oxygen higher affinity to adsorb on Ti surface as compared to nitrogen and hydrogen. We showed that stabilizing pristine Ti is challenging, and aluminum and vanadium dopants yield improved oxidation properties as compared to that of the pristine Ti [2]. These computational studies provide valuable insight into the structure, passivation effects, and surface tension of titanium, which is a key material for aerospace technology.In the second part of my presentation, I will focus on the catalyst design for clean and sustainable energy solutions. Such research has been in the forefront and is a key mission for governments across the world due to faster rise in per capita energy demand, rapid reduction in traditional energy sources, and growing efforts for reducing the incessant release of CO2 into the atmosphere. In this regard, hydrogen economy is designed to counter the fossil fuel economy. However, one of the major roadblocks for implementing the hydrogen economy in terms of technology is the sparse knowledge of physical processes involving hydrogen and their utilization. Thus, there is an active need to research atomic and molecular processes occurring at the surfaces/interfaces with hydrogen as a component. I will give an overview of some of our efforts towards developing smart catalysts for hydrogen oxidation reaction (HOR) [3]. Our aim is to develop optimized bi-functional Palladium (Pd)-metal oxides-based catalysts for Anion Exchange Membrane Fuel Cells (AEMFC). Predicting theoretically and experimentally, we established that a combined Pd-ceria catalyst is promising for HOR performance compared to their elemental components.REFERENCES[1] S. Sahoo, S. P. Alpay, and R. J. Hebert, and Surface phase diagrams of titanium in oxygen, nitrogen and hydrogen environments: A first principles analysis, Surface Science 677, 18 (2018).[2] R. S. Uwanyuze, S. P. Alpay, S. Schaffner, and S. Sahoo, A first principles analysis of oxidation in titanium alloys with aluminum and vanadium, Surface Science 719, 122026 (2022).[3] S. Sahoo, D. R. Dekel, R. Maric, and S. P. Alpay, Atomistic insights into the hydrogen oxidation reaction of palladium-ceria bifunctional catalysts for anion-exchange membrane fuel cells, ACS Catalysis 11, 2561 (2021).
Host: Avadh Saxena