Investigating The Effect of Various Parameters on The Yield of Graphene Obtained Through Graphite Exfoliation Using CO2 Supercritical Fluid

Abstract

Conventional methodsof graphene production are time-consuming and expensive.• The parameters affecting the extraction of graphene from graphite were investigated using Supercritical CO2. • Additives used in the synthesis process have the role of deactivating the surface. • The test design was done with "Design Expert" software and then tested in the laboratory.• The software results were in high agreement with the laboratory results, and mono/bilayer graphene was obtained.Due to its high penetration force and low viscosity, the Supercritical carbon dioxide (scCO2) can spread between the graphite layers, overcome van der Waals forces, and transform graphite into multilayer graphene. The results of the test plan with the Design Expert software and also the use of these results in the laboratory showed that the parameters of temperature, pressure, initial amount of graphite, addition of surfactant and solvent auxiliary, the duration of sample placement in the device, the duration of carbon dioxide gas release from the device, and the time and power of ultrasonic and centrifuge operations can accelerate the exfoliation process. The resulting graphene was characterized by TEM, RAMAN, XRD, and AFM techniques. Based on the obtained results, it was found that mono/bilayer graphene was obtained by applying optimum conditions. The results confirmed the formation of mono/bilayer graphene based on the G-Band of 1583 cm -1 in the Raman test, a wavelength of 26.44° in the XRD test, and a thickness of 1.5 nm in the AFM test. With a simple, low-cost approach, this method, without using toxic and expensive chemicals with high profitability, can replace other complex graphene production methods, such as chemical vapor leakage and plasma etching, and be chemically reduced..