White, David
(2021)
Rational Nanocarbon Composites for Novel Sensing and Catalysis.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Carbon nanomaterials have extraordinary electrical properties due to their covalent structure which enable a wide range of sensing and catalytic applications. While these structures are impressive on their own, combinations with other materials enable broader extensions of properties and applications. Most functionalization schemes to form composite materials to this date have resulted in degradation of the excellent physical properties. Careful introduction of defects or composite formation is a potential route to avoid loss of outstanding electrical properties and enable a wide range of nanomaterial composites. We first investigated how covalent organic frameworks can be used as a templating strategy to control oxidation while retaining sp2 conjugation to make holey graphene from single layer graphene. Holey graphene can then be used as a substrate for formation of size-controlled gold and palladium nanoparticles without reducing agent. Composite holey graphene nanoparticle materials exhibit strong electronic coupling between the individual nanomaterials and were leveraged to perform sensing of hydrogen sulfide and hydrogen gases for gold and palladium-based composites, respectively. This covalent organic framework template strategy can be further extended into formation of bulk holey graphene through patterning many graphene sheets at once on highly ordered pyrolytic graphite (HOPG). Once exfoliated, many solution phase reactions with metal salts were explored but silver, gold, copper, and nickel were all shown to form size-controlled nanoparticles in aqueous solution in a concentration dependent manner. So-called graphene nanoparticle compounds showed strong electronic coupling between constituent nanoparticles and nickel-based compounds showed promising activity for oxygen evolution reaction reaching mass current activities of 10,000 mA/mg of Ni at 1.7 V versus reversible hydrogen electrode. The final project leveraged growth mechanics of porous frameworks with nanocarbon materials to combine a copper catecholate based metal organic framework (MOF) grown on single-walled carbon nanotubes (SWCNTs). These composites were used to facilitate a liquid-based field-effect transistor (FET) sensing modality where ionic strength and migration of ions into pores in the presence of homologous series of carbohydrates altered observed current leading to a size selective sensor. The results of this report illustrate how careful control of nanomaterial interfaces can be leveraged for novel sensing and catalysis.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
20 January 2021 |
| Date Type: |
Publication |
| Defense Date: |
15 October 2020 |
| Approval Date: |
20 January 2021 |
| Submission Date: |
11 November 2020 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
133 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Nanomaterial composites |
| Date Deposited: |
20 Jan 2022 06:00 |
| Last Modified: |
20 Jan 2022 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/39876 |
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