氧化碎片在水溶液中对氧化石墨烯的酸性性质的关键贡献。
The critical contribution of oxidation debris on the acidic properties of graphene oxide in an aqueous solution.
机构信息
Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
出版信息
J Hazard Mater. 2021 Jan 15;402:123552. doi: 10.1016/j.jhazmat.2020.123552. Epub 2020 Jul 28.
The contribution of oxidation debris (OD) to the acidity of graphene oxide (GO) was investigated in this study. With NaCO as the titrator base, the Boehm titration results showed that the total acidity of GO in an aqueous solution decreased from 9.72 to 2.74 mmol g after a thorough removal of OD and that the total acidity of OD was 26.45 mmol g. Thermogravimetric analyses showed that the mass ratios of OD and residual graphene sheets (named bwGO) were ∼26 % and ∼73 % of the whole pristine GO, respectively. Based on the quantitative relationships between the mass ratio and acid site density, it was concluded that the total acidity of GO was equal to the sum of the acidity from bwGO and the OD contained in GO. Under alkaline conditions, the splitting and stripping of OD was attributed to the combined effect of the cleavage of H-bonds by nucleophilic attack from OH- and the electrostatic repulsion due to the ionization of carboxylic acids, in which the former became dominant when the pH shifted to neutral and weakly acidic. This study provides an explanation for the origin of GO acidity in aqueous solutions and highlights the role of OD in the chemistry of GO.
本研究考察了氧化碎片（OD）对氧化石墨烯（GO）酸度的贡献。以 NaCO 作为滴定剂碱，Boehm 滴定结果表明，彻底去除 OD 后，GO 在水溶液中的总酸度从 9.72mmol/g 降低至 2.74mmol/g，OD 的总酸度为 26.45mmol/g。热重分析表明，OD 和残留石墨烯片（命名为 bwGO）的质量比分别约为原始 GO 的 26%和 73%。基于质量比和酸位密度之间的定量关系，可以得出结论，GO 的总酸度等于 bwGO 的酸度与 GO 中所含 OD 的酸度之和。在碱性条件下，OD 的分裂和剥离归因于亲核攻击 OH-打破氢键的裂解以及羧酸离子化引起的静电排斥的共同作用，当 pH 转移到中性和弱酸性时，前者变得占主导地位。本研究为 GO 在水溶液中的酸度起源提供了一种解释，并强调了 OD 在 GO 化学中的作用。
Zotero 插件