Degree

Doctor of Philosophy (PhD)

Department

Chemical Engineering

Document Type

Dissertation

Abstract

Engineering catalytic materials is a key endeavor in the catalysis science to improve the catalytic activity of existing catalysts for specific applications and reduce the dependence on rare metals and minerals. While alloying, or mixing of metals, has been extensively studied, the focus has conventionally been placed on intermetallic phases or nanostructures such as core-shell particles, which are conceptually described by simple lattice models. This research focuses on understanding the catalytic properties of structurally ordered but compositionally disordered (or random) alloys, which have remained under-explored due to complexity at the atomic scale. Existing research focuses on synthesizing multicomponent alloys and their testing for various reactions. It falls short in elucidating the fundamental properties of such alloys, including bulk lattice constants, electronic structure, and surface reactivity toward common adsorbates such as hydrogen and oxygen. My research addresses this gap through computational modeling and theoretical calculations based on plane-wave density functional theory (PW-DFT) and Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA) methods, targeting two kinds of random alloys: Pt–3d base metal binary alloys, including Pt-Fe, Pt-Co, and Pt-Ni; and CoCrFeNi high entropy alloy (HEA). The reactivity of these alloys is mainly explored in terms of the adsorption of hydrogen and other common molecules, which are relevant to the electrochemical HER. This research demonstrates that compositional disorder can be strategically utilized to fine-tune electronic properties and surface reactivity, thereby enhancing catalytic efficiency. Further, it provides valuable insights into the development of advanced catalysts with improved performance and stability for technologically important reactions. The findings underscore the importance of considering compositional disorder in the design of catalytic materials, paving the way for more efficient and robust catalysts for various industrial applications.

Date

8-16-2024

Committee Chair

Ye Xu

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