La Grow, Alec Prochnow, Famiani, Simone, Sergides, Andreas et al. (7 more authors) (2022) Environmental STEM Study of the Oxidation Mechanism for Iron and Iron Carbide Nanoparticles. Materials. 1557. ISSN 1996-1944
Abstract
The oxidation of solution-synthesized iron (Fe) and iron carbide (Fe2C) nanoparticles was studied in an environmental scanning transmission electron microscope (ESTEM) at elevated temperatures under oxygen gas. The nanoparticles studied had a native oxide shell present, that formed after synthesis, an ~3 nm iron oxide (FexOy) shell for the Fe nanoparticles and ~2 nm for the Fe2C nanoparticles, with small void areas seen in several places between the core and shell for the Fe and an ~0.8 nm space between the core and shell for the Fe2C. The iron nanoparticles oxidized asymmetrically, with voids on the borders between the Fe core and FexOy shell increasing in size until the void coalesced, and finally the Fe core disappeared. In comparison, the oxidation of the Fe2C progressed symmetrically, with the core shrinking in the center and the outer oxide shell growing until the iron carbide had fully disappeared. Small bridges of iron oxide formed during oxidation, indicating that the Fe transitioned to the oxide shell surface across the channels, while leaving the carbon behind in the hollow core. The carbon in the carbide is hypothesized to suppress the formation of larger crystallites of iron oxide during oxidation, and alter the diffusion rates of the Fe and O during the reaction, which explains the lower sensitivity to oxidation of the Fe2C nanoparticles.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2022 by the authors |
Dates: |
|
Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) The University of York > Faculty of Sciences (York) > Electronic Engineering (York) |
Depositing User: | Pure (York) |
Date Deposited: | 23 Feb 2022 13:50 |
Last Modified: | 08 Feb 2025 00:45 |
Published Version: | https://doi.org/10.3390/ma15041557 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.3390/ma15041557 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:184048 |
Download
Filename: materials_15_01557_v2.pdf
Description: Environmental STEM Study of the Oxidation Mechanism for Iron and Iron Carbide Nanoparticles
Licence: CC-BY 2.5