电泳沉积 (EPD) 被广泛用于制备氧化石墨烯 (GO) 薄膜。然而,GO电解质在不同EPD参数下的变化及其对薄膜性能的影响还有待研究。在这项研究中,我们报告了通过电压依赖的沉淀过程将 GO 溶液分离成透明的上清液和沉淀物。我们将观察到的沉淀与电极界面处的电泳和水电解的双重效应联系起来,这有助于阳极上 GO 的质子化。EPD 期间的电流测量表明,低电位下的阳极沉积受电解液中 GO 浓度变化的控制。相反,在较高电位下,由于气体逸出导致的涂层分层对薄膜生长有显着影响。光谱和显微镜测量表明,所有电位下的沉积层都是 GO。然而,X 射线光电发射光谱 (XPS) 显示在沉积早期阶段获得的薄膜的氧官能团数量减少,用于较低的电位。这与 GO 薄片尺寸效应有关,而不是文献中报道的界面减少。这些结果提供了对电泳以及沉积 GO 的相关表面和化学结构的新见解。此外,它还提供了一种具有成本效益、可扩展的方法,可在其合成过程中以及需要分离基于 GO 的最终产品的应用中从溶液中批量分离 GO。X 射线光发射光谱 (XPS) 显示在沉积早期阶段获得的薄膜的氧官能团数量减少,用于较低的电位。这与 GO 薄片尺寸效应有关,而不是文献中报道的界面减少。这些结果提供了对电泳以及沉积 GO 的相关表面和化学结构的新见解。此外,它还提供了一种具有成本效益、可扩展的方法,可在其合成过程中以及需要分离基于 GO 的最终产品的应用中从溶液中批量分离 GO。X 射线光发射光谱 (XPS) 显示在沉积早期阶段获得的薄膜的氧官能团数量减少,用于较低的电位。这与 GO 薄片尺寸效应有关,而不是文献中报道的界面减少。这些结果提供了对电泳以及沉积 GO 的相关表面和化学结构的新见解。此外,它还提供了一种具有成本效益、可扩展的方法,可在其合成过程中以及需要分离基于 GO 的最终产品的应用中从溶液中批量分离 GO。
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Protonation of graphene oxide electrolyte during electrophoresis and effects on deposited film properties
Electrophoretic deposition (EPD) is widely used to prepare graphene oxide (GO) thin films. However, changes in the GO electrolyte under different EPD parameters and its impact on film properties are yet to be investigated. In this study, we report on GO solution separation into a clear supernatant and sediment through a voltage dependent sedimentation process. We relate the observed sedimentation to the dual effect of electrophoresis and water electrolysis at the electrode interface, which contributes to the protonation of GO at the anode. Current measurements during EPD indicate that the anodic deposition at low potentials is controlled by the concentration change of GO in the electrolyte. Conversely, at higher potentials, delamination of coating due to gas evolution has a significant influence on film growth. Spectroscopic and microscopic measurements reveal that the deposited layers at all potentials were GO. However, X-ray photoemission spectra (XPS) show reduced amounts of oxygen functionalities of films obtained at the early stages of deposition for lower potentials. This we relate to GO flake-size effects as opposed to an interface reduction reported in literature. These results present new insight into electrophoresis and associated surface and chemical structure of deposited GO. Additionally, it also provides a cost effective, scalable method of separating GO in bulk from solution during its synthesis and in applications where separation of the GO-based final product is required.