O2-oxidation of individual graphite and graphene nanoparticles in the 1200–2200 K range: Particle-to-particle variations and the evolution of the reaction rates and optical properties

Rodriguez, Daniel J.; Lau, Chris Y.; Long, Bryan A.; Tang, Susanna An; Friese, Abigail M.; Anderson, Scott L.

doi:10.1016/j.carbon.2020.10.053

Cited by 11 publications

(56 citation statements)

References 79 publications

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“…These also showed similar 1900 K sublimation kinetics, but the subsequent oxidation kinetics were more complex, with order-of-magnitude fluctuations in the oxidative mass loss rates (raw rate numbers given in the insets). As discussed previously for graphitic NPs, 5 unsteady oxidation behavior is attributed to evolution of the NP surface site distributions as the surface is etched away, removing and exposing reactive surface sites. More dramatic examples are presented below.…”

Section: -Kinetics For a Graphite Np And A Diamond Npmentioning

confidence: 73%

“…Our experimental protocols for single NP kinetics measurements have been reported previously [4][5] along with the method for TNP determination, and analysis of the uncertainties in NP mass and reaction rates (~1.3% absolute, ~0.2% relative) and TNP (~6.2% absolute, ~2% relative). Further details are given in the SI.…”

Section: Resultsmentioning

confidence: 99%

“…4 We also reported a study of O2 oxidation of graphitic NPs. 5 Etching rates peaked in the 1200 -1500 K range, dropping at higher TNP. Etching rates varied substantially from NP-to-NP and fluctuated over time for individual NPs.…”

Section: Introductionmentioning

confidence: 97%

“…To enable study of these effects, we have developed an approach to measuring surface reaction kinetics for individual NPs, held in an electrodynamic trap. [4][5] For example, we previously found that sublimation of graphitic NPs at temperatures (TNP) > 1700 K was substantially faster than the rates for bulk graphite, [6][7][8] varied by up to an order of magnitude from NP-to-NP, and slowed significantly over time, correlated with increases in optical emissivity. This behavior was attributed to the NPs initially having large, but highly variable numbers of undercoordinated surface sites, and that preferential sublimation at such sites reduces the numbers of such sites over time, reducing the rates, and modifying the optical properties.…”

Section: Introductionmentioning

confidence: 99%

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High Temperature Oxidation of Single Carbon Nanoparticles: Dependence on Surface Structure, and Probing Real-Time Structural Evolution via Kinetics.

Rodriguez

Lau

Friese

et al. 2022

Preprint

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O2-oxidation and sublimation kinetics for >30 individual nanoparticles (NPs) of five different feedstocks (graphite, graphene oxide, carbon black, diamond, and nano-onion) were measured using single nanoparticle mass spectrometry at temperatures (TNP) in 1100 – 2900 K range. It was found that oxidation, studied in the 1200 to 1600 K range, is highly sensitive to NP sur-face structure, with etching efficiencies (EEO2) varying by up to four orders of magnitude, whereas sublimation rates, significant only for TNP ≥ ~1700 K, varied by only a factor of ~3. Its sensitivity to NP surface structure makes O2 etching a good real-time structure probe, which was used to follow evolution of the NP surface structures over time as they were either etched or an-nealed at high TNP. All types of carbon NPs were found to have initial EEO2 values in the range near 10-3 Da/O2 collision, and all eventually evolved to become essentially inert to O2 (EEO2 < 10-6 Da/O2 collision), however, the dependence of EEO2 on time and mass loss was very different for NPs from different feedstocks. For example, diamond NPs evolved rapidly and monoton-ically toward inertness, and evolution occurred in both oxidizing and inert atmospheres. In contrast, graphite NPs evolved only under oxidizing conditions, and etched with complex time dependence, with multiple waves of fast-but-non-monotonic etching, separated by periods of near-inertness. Possible mechanisms to account for the complex etching behavior are pro-posed.

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Section: -Kinetics For a Graphite Np And A Diamond Npmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High Temperature Oxidation of Single Carbon Nanoparticles: Dependence on Surface Structure, and Probing Real-Time Structural Evolution via Kinetics.

Rodriguez

Lau

Friese

et al. 2022

Preprint

Self Cite

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“…The mechanical and thermal properties of graphite are deteriorated by its oxidation [9][10][11][12]. Therefore, many studies have been carried out to investigate the oxidation behavior of different graphite [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The American Society for Testing and Materials (ASTM) issued the ASTM D7542 standard to measure oxidation performances of carbon and graphite materials in 2009 (updated in 2015) [28].…”

Section: Introductionmentioning

confidence: 99%

Oxidation Experiments and Kinetics Analysis of Nuclear Graphite ET-10 by Gas Analysis and Microstructure Observation

et al. 2021

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Nuclear graphite can be used in fission and fusion systems due to its excellent nuclear performance and mechanical properties where the ability of oxidation resistance is usually concerned. Although the excellent performance of new graphite ET-10 was revealed by previous experiments regarding the accident conditions of a fission reactor, further studies are needed to oxidize the graphite under the conditions recommended by the ASTM D7542 standard. A test facility was designed and developed to oxidize the cylindrical specimen with a 10 L/min airflow. According to oxidation rates and microstructures of specimens, the chemical kinetics-controlled regime was determined as 675–750 °C, where the activation energy was obtained as 172.52 kJ/mol. The experiment results revealed the excellent ability of graphite ET-10 for oxidation resistance with lower oxidation rates and longer oxidation times compared with some mainstream graphite. The main reasons are the low contents of some impurities and the binder and the low active surface area due to the non-impregnation baking process undertaken to produce graphite with coal tar pitch coke. It should be noted that the evolution of oxidation behavior at the bottom part of the specimen (facing the airflow) was quicker than that at the upper part of the specimen. We also suggest that the abundance of oxygen supply and the good linearity of the Arrhenius plot are prerequisites of the chemical kinetics-controlled regime rather than sufficient conditions.

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Air oxidation in surface engineering of biochar-based materials: a critical review

et al. 2022

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Biochar always suffers from low porosity and/or poor surface functionality, which limit its performances. Among various surface engineering strategies, air oxidation favors both pore development and surface oxygenation for biochar. However, there is still a lack of systematic knowledge and critical perspective on air oxidation in surface engineering of biochar-based materials for various applications. Herein, this review analyzed the mechanisms of air oxidation, summarized the routes of air oxidation in surface engineering of biochar-based materials, investigated the impacts of controlling factors (including operation parameters and intrinsic biochar structure) on pore development and surface oxygenation during air oxidation, and discussed the performances of the resultant materials in pollution control, biomass catalytic conversion and energy storage. This review suggested that air oxidation could be conducted in oxidative torrefaction/pyrolysis, and applied as post-modification or pretreatment processes. Interestingly, air oxidation is efficient in enriching the heteroatoms in the heteroatom-doped biochar, and promoting the doping of metal species on biochar by enriching the anchor sites. This review also highlighted the future challenges concerning air oxidation in the surface engineering of biochar-based materials. Finally, this review was intended to attract broad attention and inspire new discoveries for promoting the application of air oxidation in surface engineering of biochar-based materials for various advanced applications. Graphical Abstract

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O2-oxidation of individual graphite and graphene nanoparticles in the 1200–2200 K range: Particle-to-particle variations and the evolution of the reaction rates and optical properties

Cited by 11 publications

References 79 publications

High Temperature Oxidation of Single Carbon Nanoparticles: Dependence on Surface Structure, and Probing Real-Time Structural Evolution via Kinetics.

High Temperature Oxidation of Single Carbon Nanoparticles: Dependence on Surface Structure, and Probing Real-Time Structural Evolution via Kinetics.

Oxidation Experiments and Kinetics Analysis of Nuclear Graphite ET-10 by Gas Analysis and Microstructure Observation

Air oxidation in surface engineering of biochar-based materials: a critical review

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