First-principles design of metal oxides for renewable energy applications
Open Access
- Author:
- Xiong, Yihuang
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 16, 2021
- Committee Members:
- Venkatraman Gopalan, Major Field Member
Ismaila Dabo, Chair & Dissertation Advisor
Raymond Schaak, Outside Unit & Field Member
Michael Janik, Outside Field Member
John Mauro, Program Head/Chair - Keywords:
- Density functional theory
Photocatalyst
Hydrogen - Abstract:
- Hydrogen is a clean and abundant fuel of high energy density, which offers a compelling alternative to petroleum-based fuels for transportation. Yet current methods for producing hydrogen rely heavily on natural gas steam reforming, which is energy-intensive and emits carbon dioxide. Therefore, there is a pressing need to develop carbon-neutral means for hydrogen generation, such as photocatalytic water splitting. This dissertation focuses on screening semiconductor materials and developing design strategies for discovering and optimizing oxide photoelectrodes. Firstly, we implement a screening protocol with co-validation between experiment and first-principles modeling to identify candidate photocatalysts for hydrogen production. Secondly, we investigate the effect of bias-induced surface reconstruction on electrochemical stability and photocatalytic performance. Finally, we present a high-throughput workflow to characterize the electronic structures of perovskite oxides. We then apply machine-learning methods to predict band alignments and identify the electronic-structure factors that govern interfacial electronic properties. These studies enable us to describe photocatalytic activity at the molecular level as a function of bulk composition and surface termination. By elucidating the separate role of bulk and interface properties, we highlight design strategies to optimize photoelectrodes for water-splitting applications.