Study on the physico-chemical properties of reduced graphene oxide with different degrees of reduction temperature

Abstract

A thermal reduction is a promising approach for the synthesis of graphene owing to its eco-friendly nature, cost-effective and mass production. However, the elucidation of the structural conformation in graphene oxide concerning for the reduction in temperature remains unclear. In this study, commercially available graphite (Gr) powder was first exploited in distilled water, which was chemically oxidized by using sulphuric acid, potassium permanganate and sodium nitrate. The chemically reduced graphene oxide (GO) was further reduced in a tubular furnace under an inert atmosphere. The Fourier transform infrared spectroscopy analysis revealed the presence of carbonyls, hydroxyls, ethers, epoxides and ketones present between the stacked layers of graphene oxide, which were eliminated in the thermally reduced graphene oxide (rGO) at the temperature range of 100–600 °C. The atomic concentration of oxygen and carbon in the graphene oxide and reduced graphene oxide were evaluated from the X-ray photoelectron spectroscopy. The atomic concentration of oxygen in graphene oxide was 29.80% (w/w) that decreased to 13.68% at 500 °C reduction temperature, confirming the elimination of oxygen-containing functional groups from the stacked structure of graphene oxide. The purity of graphene obtained from the thermal reduction of graphene oxide was 87% which has never been reported earlier.