Reducing emission of carcinogenic by-products in the production of thermally reduced graphene oxide
In the last decade, researchers have been trying to find out a simple method for large scale fabrication of high-quality graphene. A typical method for the fabrication of gram quantities of graphene materials is the oxidation of graphite to graphite oxide and consequent thermal reduction and exfoliation to reduced graphene oxide at T = ∼1000 °C. Here we show that highly reduced graphene oxide can be prepared at lower temperatures than 1000 °C while keeping the properties of graphene suitable for various electrochemical applications. The high temperature exfoliation of graphite oxide typically leads to the formation of a large amount of highly toxic volatile organic hydrocarbons such as benzene and its derivatives. The amount of volatile aromatic hydrocarbons can be reduced using low temperature exfoliation procedures that we present here. The application of a lower exfoliation temperature is highly beneficial as it also significantly reduces the etching of the graphene skeleton and the formation of toxic aromatic hydrocarbons. The effect of thermal exfoliation was investigated in detail for the temperature range of 400 °C up to 1000 °C under hydrogen as well as nitrogen atmospheres. Our findings show the route for the preparation of thermally reduced graphene oxide suitable for various electrochemical applications without the formation of toxic hydrocarbons as reaction byproducts. These findings are of high importance for the industrial scale production of thermally reduced graphene oxide.