Towards High-quality graphite oxide from graphite – Systemization of the balance in oxidative and mechanical forces for yield enhancement

Despite intensive research on graphene, large-scale production of high-quality graphene oxide/graphite oxide (GO) is challenging. The labour-intensive oxidative mechanical exfoliation is frequently found to be the rate-limiting step. In this study, we report ways to improve GO quality and yield by modifying two promising scalable process variants of Hummers method, viz., Kim’s and Tour’s method for GO production. To achieve a desired crystallite size with minimal defects, we report possible adjustments to the exfoliation process by evaluating the oxidation mechanism against GO’s structural integrity. The modifications such as altering the quantity of the oxidant, the duration of ultrasonic-assisted oxidation and the order of washing cycles improved the oxidation efficiency resulting in yield enhancement of defect-free GO. The structure and quality of the synthesized GO were found to depend on the rigorousness of washing cycles and the quantity of oxidant used rather than on the nature of the oxidant alone.