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Extraordinary thermal behavior of graphene oxide in air for electrode applications
Nanoscale Advances ( IF 4.6 ) Pub Date : 2021-1-2 , DOI: 10.1039/d0na00805b
Joon Young Cho 1, 2 , Jung Hoon Kim 1 , Joong Tark Han 1, 2
Affiliation  

The thermal stability of solution-exfoliated graphene oxide (GO) in air is one of the most important physical properties influencing its potential applications. To date, the majority of the GO prepared by the KMnO4-based oxidation of graphite is thermally unstable in air due to the presence of highly oxidative functional groups, such as carboxyl and lactol groups that possess defective basal plane structures. Here, we demonstrate that less defective and metal ion-free GO nanosheets including those with a high oxidation level can remain very stable even above 300 °C under ambient conditions. These GO nanosheets were produced by the exfoliation of graphite oxide fabricated by the modified Brodie method in NH4OH solution, effectively excluding metal ions that can promote the thermal decomposition of GO in air at elevated temperatures. The deoxygenation of ammonia-assisted GO (AGO) was initiated at temperatures above 200 °C, while GO exfoliated in the KOH solution (KGO) decomposed, even at 180 °C. Notably, AGO was exceptionally resistant at 400 °C, even at a very slow heating rate of 2 °C min−1. Conversely, KGO was significantly oxidized, even at 250 °C. The superior thermal stability of AGO is favorable for the fabrication of conductive surface graphene films and conductive fibers by low-temperature annealing.

中文翻译:

用于电极应用的氧化石墨烯在空气中的非凡热行为

溶液剥离氧化石墨烯(GO)在空气中的热稳定性是影响其潜在应用的最重要的物理性质之一。迄今为止,通过基于 KMnO 4的石墨氧化制备的大多数 GO 在空气中是热不稳定的,因为存在具有缺陷基面结构的高氧化官能团,例如羧基和乳醇基团。在这里,我们证明了缺陷较少且不含金属离子的 GO 纳米片,包括那些具有高氧化水平的纳米片,即使在环境条件下高于 300°C 也可以保持非常稳定。这些 GO 纳米片是由改进的 Brodie 方法在 NH 4中剥离的氧化石墨制成的。OH 溶液,有效排除了高温下可促进 GO 在空气中热分解的金属离子。氨辅助 GO (AGO) 的脱氧在高于 200 °C 的温度下开始,而在 KOH 溶液 (KGO) 中脱落的 GO 即使在 180 °C 时也会分解。值得注意的是,AGO 在 400 °C 时具有异常的耐受性,即使在 2 °C min -1的非常缓慢的加热速率下也是如此。相反,KGO 被显着氧化,即使在 250 °C 时也是如此。AGO优异的热稳定性有利于通过低温退火制备导电表面石墨烯薄膜和导电纤维。
更新日期:2021-01-20
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