We demonstrate a new, facile gas-phase electrostatic approach to successfully quantify equivalent surface area of graphene oxide (GO) colloid on a number basis. Mobility diameter (d_p,m)-based distribution and the corresponding equivalent surface area (SA) of GO colloids (i.e., with different lateral aspect ratios) were able to be identified by electrospray-differential mobility analysis (ES-DMA) coupled to a condensation particle counter (CPC) and an aerosol surface area analyzer (ASAA). A correlation of SA ∝ d_p,m^2.0 was established using the ES-DMA-CPC/ASAA, which is consistent with the observation by the 2-dimensional image analysis of size-selected GOs. An ultrafast surface area measurement of GO colloid was achieved via a direct coupling of ES with a combination of ASAA and CPC (i.e., measurement time was 2 min per sample; without size classification). The measured equivalent surface area of GO was ∼202 ± 7 m² g^–1, which is comparable to Brunauer–Emmett–Teller (BET) surface area, ∼240 ± 59 m² g^–1. The gas-phase electrostatic approach proposed in this study has the superior advantages of being fast, requiring no elaborate drying process, and requiring only a very small amount of sample (i.e., <0.01 mg). To the best of our knowledge, this is the first study of using an aerosol-based electrostatic coupling technique to obtain the equivalent surface area of graphene oxide on a number basis with a high precision of measurement.

中文翻译：

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气相静电法量化纳米片氧化石墨烯胶体的表面积

我们展示了一种新的，简便的气相静电方法，可以成功地在数量上量化氧化石墨烯（GO）胶体的当量表面积。可以通过电喷雾-差动迁移率分析（ES-DMA）结合GO胶体的基于迁移率直径（d _p，m）的分布和相应的等效表面积（SA）（即具有不同的横向长宽比）进行识别。冷凝粒子计数器（CPC）和气溶胶表面积分析仪（ASAA）。SA ∝ d _p，m ^{2.0的相关性}通过使用ES-DMA-CPC / ASAA建立的数据与通过大小选择的GO进行二维图像分析得出的结果一致。GO胶体的超快表面积测量是通过ES与ASAA和CPC的直接耦合来实现的（即，每个样品的测量时间为2分钟；没有尺寸分类）。GO的测量等效表面积为〜202±7 m ² g ^–1，与Brunauer–Emmett–Teller（BET）表面积为〜240±59 m ² g ^–1相近。。本研究中提出的气相静电方法具有快速，无需复杂的干燥过程以及仅需极少量样品（即<0.01 mg）的优越性。据我们所知，这是首次使用基于气溶胶的静电耦合技术以高测量精度获得基于数量的氧化石墨烯的等效表面积的研究。