INVESTIGATION THE EFFECT OF pH VALUE IN GRAPHENE OXIDE PRODUCTION

Abstract

In recent years, the use of graphene oxide (GO) in advanced application areas has attracted great interest. GO consists of a carbon basal plane containing various functional groups. Thanks to its properties, GO can improve the properties of the materials to which it is added. Therefore, GO is used in various photocatalytic, sensor and battery applications. Moreover, large-scale production of graphene, which has outstanding propertiessuch as high electrical conductivity, thermal conductivity, and high surface area, is possible by reduction of GO. Therefore, quality and controllable GO production is required. GO is generally produced with the Hummer's Method, which is a suitable chemical method for industrial production. In Hummer's Method, graphite oxide is obtained by oxidizing of graphite with the help of oxidizing agents. Afterwards, GO is obtained by exfoliating of the graphite oxide. However, the original Hummer Method has many disadvantages due to the emission of harmful, dangerous gases and its low efficiency. Many Hummer's methods have been derived by researchers from past to present. As a result of various modifications, the Modified Hummer's Method, which includes efficient, non-toxic and harmless production method steps, was preferred in GO production. Each stage of production process affects the properties and structures of the obtained GO. Understanding the effect of GO production parameters on GO structure, is important for its use in electronics, optics, biological, and graphene production applications. In Hummer's Method, after the oxidation of graphite, washing with HCl followed by distilled water is applied to remove impurities. The final step, which is the washing process, is an important step for the final structure properties of GO. In this study, the effect of pH value on the obtained GO structure was investigated by using the Modified Hummer's Method that we developed. Structural characterization studies of GO samples from solutions at different pH levels were performed using X-Ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet - Visible Spectrophotometer (UV-Vis). According to the obtained results, it was determined that the difference in pH level of solution changed the structure of GO and affected the degree of exfoliation. Keywords: Graphene oxide, pH, Purification, Modified Hummer’s, XRD, FTIR.