Engineering material interfaces for advanced thermo‑optical‑electrochemical energy systems

Woo, Ho Kun

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https://hdl.handle.net/2142/130162 Copy

Description

Title

Engineering material interfaces for advanced thermo‑optical‑electrochemical energy systems

Author(s)

Woo, Ho Kun

Issue Date

2025-07-11

Director of Research (if dissertation) or Advisor (if thesis)

Cai, Lili

Doctoral Committee Chair(s)

Cai, Lili

Committee Member(s)

• Lee, Tonghun
• Yang, Hong
• He, Jiajun

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Energy conversion
• Heat transfer
• Electrochemical conversion

Abstract

Rising concentrations of greenhouse gas continue to fuel global warming, driving a critical need for technologies that both curb energy demand and valorize greenhouse‐gas emissions. This dissertation advances a materials‐interface approach that tackles the problem from two complementary angles: (i) optical–thermal system management for mitigating energy consumption and (ii) chemical energy conversion approaches for greenhouse gas mitigation. First, spectrally engineered metal-based nanostructured surfaces are designed and fabricated through scalable nanosphere and nanoimprint lithography. The coatings reflect mid-infrared radiation, generating localized radiative heating without external energy consumption, while preserving tunable visible functionalities such as transparency or aesthetic coloration. Building on these photonic design principles, the system extends radiative thermal control to a thermally regenerative electrochemical cycle, where a passive temperature gradient is harnessed to generate electricity from ambient heat without external charging. The second research thrust addresses methane, a potent greenhouse gas with a global warming potential approximately 25 times that of carbon dioxide, yet an abundant and underutilized carbon feedstock. Two reaction pathways under environmentally benign conditions are demonstrated. In the first, a photoelectrochemical scheme employs defect-engineered catalysts to suppress over-oxidation, achieving high Faradaic efficiency for the conversion of methane into liquid products. This is accomplished not only by reducing oxidation potential but also by minimizing the generation of hydroxyl radicals that typically lead to complete oxidation. In the second approach, an electro-Fenton-based system couples two-electron oxygen reduction at a cathode with photoelectrochemical glycerol oxidation at the anode, enabling bias-free methane oxidation under ambient conditions. Across both routes, systematic tuning of surface chemistry, electrolyte composition, and gas flow was investigated the optimized the methane valorization. By controlling heat and charge transport at the micro- and nanoscale, this work demonstrates how opto-thermal and electrochemical systems can be synergistically designed to reduce fossil fuel dependence, valorize greenhouse gases, and expand the functional boundaries of sustainable energy technologies. The findings collectively emphasize the transformative potential of materials science in shaping low-carbon, high-efficiency energy infrastructures for the future.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/130162

Copyright and License Information

Copyright 2025 Woo, Ho Kun

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