▎ 摘　　要

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.