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arXiv 2008.05078physics.chem-ph
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在1200至2200 K范围内单个石墨和石墨烯纳米颗粒的O2-Oxidation:颗粒与颗粒之间的变化以及反应速率和光学性质的演变

O2-Oxidation of Individual Graphite and Graphene Nanoparticles in the 1200 to 2200 K Range: Particle-to-Particle Variations and the Evolution of the Reaction Rates and Optical Properties

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

摘要:

在不同的氧分压下,使用单个纳米颗粒质谱法,研究了单个石墨和石墨烯片晶纳米颗粒(NPs)的O2氧化动力学随温度(1200至2200 K)的变化。在动力学研究期间,通过测量NP热发射光谱来测量NP温度(TNP)。发现初始氧化效率在1200至1500 K范围内达到峰值,当TNP高于2000 K时下降一个数量级。有大NP到NP的氧化速率的变化,归因于NP表面结构的变化。此外,随着NP反应,氧化效率非单调地降低10至300倍。这种反应性的演变归因于由于氧化和退火的组合而引起的NP表面结构的变化。光学性质,包括发射率的波长依赖性和532 nm加热激光的吸收截面,也倾向于随着NP氧化而演变,但对于每个单独的NP不同,推测反映了初始结构的差异,以及它们在不同反应条件下如何演变。

英文摘要:

The kinetics for O2 oxidation of individual graphite and graphene platelet nanoparticles (NPs) were studied as a function of temperature (1200 to 2200 K) at varying oxygen partial pressures, using a single nanoparticle mass spectrometry method. NP temperature (TNP) was measured by measuring the NP thermal emission spectra during the kinetics studies. The initial oxidation efficiency is found to peak in the 1200 to 1500 K range, dropping by an order of magnitude as TNP was increased above 2000 K. There were large NP-to-NP variations in the oxidation rates, attributed to variations in the NP surface structure. In addition, the oxidation efficiencies decreased, non-monotonically, as the NPs reacted, by factors of between 10 and 300. This evolution of reactivity is attributed to changes in the NP surface structure due to the combination of oxidation and annealing. The optical properties, including wavelength dependence of the emissivity, and the absorption cross section for the 532 nm heating laser, also tend to evolve as the NPs oxidize, but differently for each individual NP, presumably reflecting differences in the initial structures, and how they evolve under different reaction conditions.

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