Kinetics of the high temperature oxygen exchange reaction on 238PuO2 powder

Whiting, Christofer E.; Du, Miting; Felker, L. K.; Wham, R.M.; Barklay, Chadwick D.; Kramer, Daniel P.

doi:10.1016/j.jnucmat.2015.10.020

Cited by 3 publications

(2 citation statements)

References 42 publications

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“…It has been postulated that low concentrations of oxygen are likely released by PuO 2 via oxygen exchange and diffusion mechanisms over the lifetime of these deep-space missions. The effect of oxygen on the kinetics of La 3– x Te 4 /Ni interfaces, therefore, cannot be neglected Figure illustrates the in situ TEM analysis of a fully oxidized La 3– x Te 4 –Ni sample.…”

Section: Resultsmentioning

confidence: 99%

“…The effect of oxygen on the kinetics of La 3−x Te 4 /Ni interfaces, therefore, cannot be neglected. 35 Figure 7 illustrates the in situ TEM analysis of a fully oxidized La 3−x Te 4 −Ni sample. The red arrow in the EDS spectrum acquired at the region of interest (ROI) (at 25 °C, before heating) (Figure 7a) indicates a distinctive oxygen peak.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

et al. 2021

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Lanthanum telluride (La 3−x Te 4 ) is a high-performance, next-generation thermoelectric material with a thermoelectric dimensionless figure of merit (zT) of 1.1 at 1273 K (x = 0.23) and has potential applications in radioisotope thermoelectric generators (RTGs) to power the space missions conducted by National Aeronautics and Space Administration (NASA). It has been shown that the zT can be increased by 30% when nickel (Ni) nanoparticle inclusions are introduced to the La 3−x Te 4 matrix. The coherent interfaces between La 3−x Te 4 and Ni are likely a key factor determining the stability and performance of the La 3−x Te 4 −Ni composites, but their role and nature are not well understood. It is important to determine the stability of the La 3−x Te 4 /Ni interface in deep-space conditions, in addition to the effect of heat and oxygen on the mechanisms and kinetics of interface degradation. Here, we show the high-resolution structural characterization and the epitaxial crystallographic relationship of La 3−x Te 4 −Ni thermoelectric composites and their interfaces at high-vacuum and ambient-temperature conditions using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). We further demonstrate the La 3−x Te 4 /Ni interface degradation and Ni diffusion over its operating temperature range (25−1000 °C), in the presence and absence of oxygen, in real time, using in situ TEM.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

et al. 2021

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Isotopic Oxygen Exchange between CeO₂ and O₂: A Heteroexchange Mechanism

2019

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Isotopic oxygen exchange (IOE) is a crucial reaction required in the purification of 238PuO2 which has been used as an important fuel in space exploration. Experimental studies on the IOE between 238PuO2 and O2 are costly and hazardous due to the radioactivity. With extremely similar crystal structures, CeO2 could be a fair surrogate for 238PuO2 in the investigation of physicochemical properties. Here, we perform density functional theory calculations to simulate the IOE between CeO2 and O2, wherein a heteroexchange mechanism is proposed. Estimated reaction barriers for CeO2/O2 and 238PuO2/O2 systems are comparable (25.8 and 29.3 kcal mol−1 respectively), indicating CeO2 is a potential substitute for 238PuO2 in an IOE reaction. Our study could be useful for experimental chemists to probe more complicated IOE mechanisms for both CeO2/O2 and PuO2/O2.

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Microstructure evolution of gadolinium doped cerium oxide under large thermal gradients

Maruyama

Nino

2021

Ceramics International

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Kinetics of the high temperature oxygen exchange reaction on 238PuO2 powder

Cited by 3 publications

References 42 publications

Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

Isotopic Oxygen Exchange between CeO₂ and O₂: A Heteroexchange Mechanism

Microstructure evolution of gadolinium doped cerium oxide under large thermal gradients

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Kinetics of the high temperature oxygen exchange reaction on 238PuO2 powder

Cited by 3 publications

References 42 publications

Uncovering the Structure and Stability of Thermoelectric La3–xTe4–Ni Composites Using High-Resolution and In Situ TEM

Uncovering the Structure and Stability of Thermoelectric La3–xTe4–Ni Composites Using High-Resolution and In Situ TEM

Isotopic Oxygen Exchange between CeO2 and O2: A Heteroexchange Mechanism

Microstructure evolution of gadolinium doped cerium oxide under large thermal gradients

Contact Info

Product

Resources

About

Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

Uncovering the Structure and Stability of Thermoelectric La_3–xTe₄–Ni Composites Using High-Resolution and In Situ TEM

Isotopic Oxygen Exchange between CeO₂ and O₂: A Heteroexchange Mechanism