Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

The Effects of Electrical and Mechanical Modulation on the Chemical Reactivity of Graphene

Kim, Min A (2021) The Effects of Electrical and Mechanical Modulation on the Chemical Reactivity of Graphene. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

[img] PDF
Restricted to University of Pittsburgh users only until 8 October 2023.

Download (7MB) | Request a Copy

Abstract

Extreme surface to volume ratio of graphene makes graphene widely open to various reactions; chemistry of graphene is of great interest to fine-tune electronic, chemical, and mechanical properties of graphene, and a better understanding of the factors that impact its chemical reactivity is an invaluable part of graphene chemistry. In this dissertation, dynamic modulation of graphene properties and their effects on the chemical reactivity of graphene are investigated.
A brief background on the history, synthesis, and characterization methods of graphene is summarized in chapter 1. In chapter 2, how graphene interacts with ambient-found species under electrical doping was studied. Electrical doping has significant advantage over chemical doping with in-situ controllability. Static back gating resulted doping hysteresis, which we explained using a charge trapping/de-trapping mechanism.
Efficient electrical doping method was developed to further investigate its effects on the reactivity of graphene in chapter 3. Graphene was heated photothermally in air to ca. 240 ºC and monitored using Raman spectroscopy. Electrically doped graphene showed increased rate in the oxidation reaction. Density functional theory (DFT) calculations indicate that the activation barriers for O2 insertion and CO2 desorption decrease with an electric field. This is the first example of charge-doping induced reactivity enhancement in macroscopic-sized solid-state material.
In chapter 4, the mechanical modulation of graphene and its effects were investigated. Preliminary results suggested an enhanced electrochemical catalytic activity of graphene as well as the electrochemical oxidation itself. The catalytic role of graphene was further investigated and found that applied tensile strain of 0.2 % on a graphene electrode led to a 1~3 % increase of hydrogen evolution reaction (HER) current. Tensile strain increases HER activity while compressive strain decreases it. DFT calculations show increasing H atom adsorption energy with growing tensile strain, leading to a corresponding enhancement of current density in HER.


Share

Citation/Export:
Social Networking:
Share |

Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Kim, Min Amik96@pitt.edumik960000-0002-6575-6410
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairLiu, Haitaohliu@pitt.edu
Committee MemberStar, Alexanderastar@pitt.edu
Committee MemberMillstone, Jilljem210@pitt.edu
Committee MemberLi, Leilel55@pitt.edu
Date: 8 October 2021
Date Type: Publication
Defense Date: 21 July 2021
Approval Date: 8 October 2021
Submission Date: 7 July 2021
Access Restriction: 2 year -- Restrict access to University of Pittsburgh for a period of 2 years.
Number of Pages: 191
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: graphene, 2D materials, reactivity, catalysis, oxidation, hydrogen evolution reaction, electrical modulation, electrical doping, mechanical modulation, strain engineering
Date Deposited: 08 Oct 2021 20:22
Last Modified: 08 Oct 2021 20:22
URI: http://d-scholarship.pitt.edu/id/eprint/41400

Metrics

Monthly Views for the past 3 years

Plum Analytics


Actions (login required)

View Item View Item