The Characterization of Purified Citrate-Coated Cerium Oxide Nanoparticles Prepared via Hydrothermal Synthesis

Authors

Matthew L. Hancock, University of KentuckyFollow
Robert A. Yokel, University of KentuckyFollow
Matthew J. Beck, University of KentuckyFollow
Julie L. Calahan, University of KentuckyFollow
Travis W. Jarrells, University of KentuckyFollow
Eric J. Munson, University of KentuckyFollow
George A. Olaniyan, University of Kentucky
Eric A. Grulke, University of KentuckyFollow

Abstract

Hypothesis

Cerium oxide nanoparticles were synthesized using a hydrothermal approach with citric acid as a stabilizing agent. Citric acid adsorption onto the nanoceria particle surface can cease particle formation and create a stable dispersion for an extended shelf life. The product was dialyzed immediately following the synthesis to remove unreacted cerium that could contribute to biological effects. Nanoparticle characterization results are expected to help identify the surface citrate bonding structure.

Experiments

Many characterization techniques were utilized to determine size, morphology, surface properties, and citrate complexation on the nanoceria particle surface. These included transmission electron microscopy, electron energy loss spectroscopy, dynamic light scattering, x-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV–Vis absorption spectroscopy, zeta potential, and ¹³C solid-state nuclear magnetic resonance spectroscopy.

Findings

Primary particles were hexagonal, determined to be 4.2 nm in diameter. The hydrodynamic diameter of the dialyzed product was 10.8 nm. Each agglomerate was estimated to contain an average of 5.7 particles. The citrate coating contained 2.8 citrate molecules/nm², corresponding to an approximate citrate monolayer. Citrate complexation with the nanoceria surface includes the central carboxyl geminal to the hydroxyl and perhaps one of its terminal carboxyl groups.

Document Type

Article

Publication Date

1-1-2021

Notes/Citation Information

Published in Applied Surface Science, v. 535, 147681.

© 2020 Elsevier B.V.

© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/.

This article is freely available before October 26, 2020 at: https://authors.elsevier.com/a/1bhqUcXa%7EwHmZ

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.apsusc.2020.147681

Funding Information

This work is funded by the National Institutes of Health under Award Number R01GM109195.

Repository Citation

Hancock, Matthew L.; Yokel, Robert A.; Beck, Matthew J.; Calahan, Julie L.; Jarrells, Travis W.; Munson, Eric J.; Olaniyan, George A.; and Grulke, Eric A., "The Characterization of Purified Citrate-Coated Cerium Oxide Nanoparticles Prepared via Hydrothermal Synthesis" (2021). Chemical and Materials Engineering Faculty Publications. 73.
https://uknowledge.uky.edu/cme_facpub/73