Preparation of few-layer graphene oxide with few defects via the Fenton reaction with green reagents

Graphene oxide is a precursor of scale-up production of graphene. Under the conditions of 50 °C and pH 3, flake graphite was oxidized by Fenton reaction mediated by ferrous ions, and then graphene oxide was obtained via exfoliation in an ultrasonic field. The carbon yield of graphene oxide reached 12.3% after the Fenton reaction with the addition of ferrous ions thrice. The transparency of graphene oxide sheets was confirmed by optical microscopy. According to the results of atomic force microscopy, transmission electron microscopy, infrared spectroscopy and Raman spectroscopy, the product consisted of 2–4 layers, and contained carboxyl, hydroxyl and ether bonds, consistent with the characteristics of graphene oxide. Its ID/IG value was 0.37, much lower than that (ca. 1) of graphene oxide prepared by modified Hummers methods, indicating that the product possessed fewer surface defects and higher quality. Compared with the modified Hummers method, the present method has advantages of mild preparation conditions, shorter preparation time and eco-friendliness.