Investigation of highly oxidized graphene oxide (GO) by solid-state nuclear magnetic resonance (NMR) spectroscopy has revealed an exceptional level of hitherto undiscovered structural complexity. A number of chemical moieties were observed for the first time, such as terminal esters, furanic carbons, phenolic carbons, and three distinct aromatic and two distinct alkoxy carbon moieties. Quantitative one-dimensional (1D) and two-dimensional (2D) ¹³C{¹H} NMR spectroscopy established the relative populations and connectivity of these different moieties to provide a consistent "local" chemical structure model. An inferred 2 nm GO sheet size from a very large (∼20%) edge carbon fraction by NMR analysis is at odds with the >20 nm sheet size determined from microscopy and dynamic light scattering. A proposed kirigami model where extensive internal cuts/tears in the basal plane provide the necessary edge sites is presented as a resolution to these divergent results. We expect this work to expand the fundamental understanding of this complex material and enable greater control of the GO structure.

Item Type:	Refereed Article
Keywords:	graphene oxide structure, solid-state NMR, 2D NMR, 2D 13C-1H heteronuclear correlation NMR, kirigami, furanic carbons
Research Division:	Chemical Sciences
Research Group:	Macromolecular and materials chemistry
Research Field:	Structure and dynamics of materials
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the chemical sciences
UTAS Author:	Thickett, SC (Associate Professor Stuart Thickett)
ID Code:	145191
Year Published:	2021
Web of Science® Times Cited:	7
Deposited By:	Chemistry
Deposited On:	2021-07-08
Last Modified:	2021-09-28
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