Date of Completion

8-20-2019

Embargo Period

8-19-2024

Keywords

High temperature PEMFC, Catalyst layer, Flame spray pyrolysis, MoO3 nanoribbons, Hydrothermal method, Chemiresistive, Ammonia gas sensor, DFT simulation, Surface acoustic wave, ZnO seed layer, Temperature effect, Resonant Frequency

Major Advisor

Radenka Maric

Co-Major Advisor

Yu Lei

Associate Advisor

Pu-xian Gao

Associate Advisor

Liang Zhang

Associate Advisor

Ugur Pasaogullari

Field of Study

Materials Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Functional nanomaterials synthesized by a flame spray pyrolysis process called reactive spray deposition technology (RSDT) and a hydrothermal method along with drop-casting were investigated for energy and sensor applications in this dissertation. For a high temperature proton exchange membrane fuel cell (HT-PEMFC) application, RSDT was utilized to manufacture the nanostructured catalyst layer (CL). The study of the influence of binder content in the catalyst coated-membrane (CCM) was conducted in terms of optimization for the performance of HT-PEMFC. As sensor applications, two different types of detection technique are introduced: metal oxide-based resistor and surface acoustic wave (SAW) based detector. Especially, two case studies using hydrothermally grown alpha-phase molybdenum tri-oxide (α-MoO3) and Tin (Sn)-doped α-MoO3 nanoribbons as sensing films are discussed for ammonia (NH3) gas detection. In addition, the in-depth study based on density functional theory (DFT) simulations is presented to shed light on the gas sensing mechanism of MoO3 towards NH3 and the critical role of Sn as a dopant in the MoO3 nanoribbon-based sensor performance. Moreover, the research of SAW based detector is mainly focused on device design, fabrication and characterization, while its potential sensing application will be discussed in conclusions and future work.

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