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Thermal stability of oxygen functionalization in v-CNTs by low kinetic energy ion irradiation
Vacuum ( IF 4 ) Pub Date : 2021-06-30 , DOI: 10.1016/j.vacuum.2021.110423
Selene Acosta , Ayrton Sierra-Castillo , Jean-François Colomer , Rony Snyders , Mildred Quintana , Chris Ewels , Carla Bittencourt

Vertically aligned multiwalled carbon nanotubes synthetized by catalytic chemical vapor deposition are irradiated with low kinetic energy oxygen ions to graft oxygen functional groups at their surface. Subsequently, the thermal stability of these functional groups is investigated by heating the sample progressively to 200, 300, 400 and 500 °C. X-Ray photoelectron spectroscopy (XPS) is used to analyze the atomic concentration and chemical configuration at the sample surface after each stage. Scanning and transmission electron microscopies are used to observe the morphology of the nanotubes after the thermal treatment. The solvent-free functionalization is carried out in 10 min reaching an oxygen atomic concentration of 17.2 at.%, with no impurities introduced. At the end of the thermal treatment, the relative oxygen content drops to 5.6 at.%. XPS analysis indicates that four oxygen groups produced by the ion irradiation: epoxide, hydroxyl, carbonyl, and carboxyl groups, with the epoxides being the least stable and the carbonyls the most stable. Combining low kinetic energy ion-irradiation with a post-thermal anneal is shown to be an effective route to simultaneously control both sample oxygen content and the ratio of different oxygenated functional groups.



中文翻译:

低动能离子辐照对 v-CNTs 中氧官能化的热稳定性

通过催化化学气相沉积合成的垂直排列的多壁碳纳米管用低动能氧离子辐照以在其表面接枝氧官能团。随后,通过将样品逐渐加热到 200、300、400 和 500 °C 来研究这些官能团的热稳定性。X 射线光电子能谱 (XPS) 用于分析每个阶段后样品表面的原子浓度和化学构型。使用扫描和透射电子显微镜观察热处理后纳米管的形态。无溶剂官能化在 10 分钟内进行,氧原子浓度达到 17.2 at.%,没有引入杂质。在热处理结束时,相对氧含量下降到 5.6 at.%。XPS 分析表明离子辐照产生四个氧基团:环氧化物、羟基、羰基和羧基,其中环氧化物最不稳定,羰基最稳定。将低动能离子辐照与后热退火相结合被证明是同时控制样品氧含量和不同含氧官能团比例的有效途径。

更新日期:2021-07-13
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