Author

Xiang Li

Abstract

Titanium dioxide (TiO2) is one of the most extensively studied compounds in materials science. Since the first successful fabrication of highly ordered TiO2 nanotubes (TiO2-NTs) arrays via electrochemical anodization in ’90s, thousands of publications have focused on the growth, properties, and applications of these versatile nanostructures. In the present study, anodization conditions were found to be the key determinants for TiO2-NTs’ structures and properties. In fact, this work demonstrates that tuning anodization conditions leads to tailoring TiO2-NTs’ for distinctive electrochemical applications. Deconvoluting myriad factors, for example temperature, electrolyte, reaction time, and potential, which govern the anodized products properties, was possible by examining the correlation anodization parameters to TiO2-NTs characteristics. In present study, a synergistic experimental approach was employed in order to investigate how anodization parameters affect the anodized products structures and properties. This work clearly delineates that the nanoscale geometry (tube diameter, surface area, and self-ordering degree) of TiO2-NTs is highly tailorable by tuning the anodization parameters. Upon achieving well-controlled TiO2-NTs, they exhibited good electrosorption capacity and selectivity in the alkaline metal ions electrosorption test. In addition, a novel strategy to fabricate hierarchically flow-through 3D Ti/TiO2 NT electrodes for hydrogen evolution reaction (HER) was developed. The 3D Ti/TiO2 NT electrodes reported here take advantage of 3D printing and in-situ anodization to achieve efficient HER electrocatalysis. Most importantly, the preparation of the 3D Ti/TiO2 NT electrode is facile and readily scalable since the fabrication does not include time- and energy-consuming processes such as complex precursor preparation and high-temperature heat treatments. The large-scale construction of 3D Ti/TiO2 NT does not require high capital cost and the flow-through feature makes it very appealing for continuous, industrial- scale hydrogen production. This study also provides evidence that the TiO2 NT on the surface of the 3D Ti templates is the active catalytic surface promoting HER, by a two-step mechanism that contributes to the faster rate of the overall process. The 3D Ti templates contribute to fast HER reaction rates in terms of offering a seamless electron transfer network and large exposed active sites, namely TiO2 NT.

Publication Date

6-8-2018

Document Type

Dissertation

Student Type

Graduate

Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering (KGCOE)

Advisor

Patricia Taboada-Serrano

Advisor/Committee Member

Blanca Lapizco-Encinas

Advisor/Committee Member

Jiandi Wan

Campus

RIT – Main Campus

Share

COinS