A thermal method for obtention of 2 to 3 reduced graphene oxide layers from graphene oxide

In this work, a thermal reduction method was developed to obtain reduced graphene oxide (rGO) with 2 or 3 layers from graphene oxide (GO). The GO X-ray diffraction (XRD) patterns presented diffraction peak at 2θ = 10°, which is related to (002) reflection. After heat treatment under nitrogen (N2(g)) atmosphere, this peak was shifted to 2θ = 25°, presenting an interlayer distance of 3.8 A, associated to GO reduction. BET analysis of modified GO samples identified an average pore diameter of 45.38 A and surface area of 23.06 m2/g. In the case of rGO1, rGO2 and rGO3 samples, they presented surface areas from 32.47 to 612.74 m2/g and an average pore diameter of 108.21–149.54 m2/g. Thermogravimetric analysis (TGA) indicated a higher mass loss between 150 and 230 °C. Raman spectra showed ID/IG ratios of rGO samples were higher than GO (1.36-GO; 1.45-rGO1, 1.87-rGO3) due to reducing GO and increasing sp2 clusters. XPS analysis revealed that the main carbon species in the samples were sp2-type bonds (14.99 at% for the GO and 47.85 at% for rGO3). The FTIR spectra of rGO1, rGO2 and rGO3 samples presented peaks at 3454.22 cm−1 (hydroxyl) and 1077.43 cm−1 (C–O).