relation: http://d-scholarship-dev.library.pitt.edu/33154/
title: NANOSCALE SCANNING ELECTROCHEMICAL MICROSCOPY FOR STUDY OF CARBON MATERIALS AND HIGH-RESOLUTION IMAGING
creator: Chen, Ran
description: The nanogap voltammetry based on Scanning Electrochemical Microscopy (SECM) can monitor and study fast electron transfer (ET) reaction on macroscopic substrates of interest. The understanding of the electrochemical reactivity of carbon nanomaterials is of great importance not only for the application purposes, but also for fundamental electrochemistry.  There are controversies about how the electronical reactivity of these materials depend on the electronic structures, defects and contamination. One theme of my PhD work is to study the electrochemical reactivity of various carbon nanomaterials using nanogap voltammetry based on SECM.   On the other hand, SECM at nanometer scale is a powerful technique, with unique advantages and unprecedented measurement capabilities, such as very high spatial resolution for surface imaging. However, it has been challenging to reliably characterize the size and geometry of the nanometer-size electrodes. The other aim of my PhD work is the development of methods for fabricating and characterizing nanoelectrodes for SECM.  Therefore, this thesis is based on two sections. In the first section, I fabricate graphene electrodes based on graphene grown by chemical vapor deposition, and apply nanogap voltammetry to study the ultrafast ET kinetics at graphene. I also study the ultrafast ET kinetics at highly ordered pyrolytic graphite (HOPG) with nanogap voltammetry. In the second section, I develop carbon nanoprobes with high electrochemical reactivity and well-controlled size and geometry based on chemical vapor deposition of carbon in quartz nanopipets. I also characterized the size and geometry of the nanopipets that support interfaces between two immiscible electrolyte solutions (ITIES). I then prove the utility of such nanopipets by the SECM imaging on 100 nm diameter Si3N4 nanopores.
date: 2018-01-31
type: University of Pittsburgh ETD
type: PeerReviewed
format: application/pdf
language: en
identifier: http://d-scholarship-dev.library.pitt.edu/33154/1/ETD%208-27R_Chen.pdf
identifier:   Chen, Ran  (2018) NANOSCALE SCANNING ELECTROCHEMICAL MICROSCOPY FOR STUDY OF CARBON MATERIALS AND HIGH-RESOLUTION IMAGING.  Doctoral Dissertation, University of Pittsburgh.    (Unpublished)