High-quality graphene thin films synthesized by H-2 ambient-annealing of reduced graphene oxide sheets

Abstract

Highly conductive low-oxygen graphene thin films were produced by thermal annealing of chemically reduced graphene oxide(RGO) sheets under H2 ambient. X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy and X-rayphotoelectron spectroscopy measurements showed that the thermal annealing efficiently removed residual oxygen-containingfunctional groups on the surface of the chemically reduced RGO sheets and simultaneously recovered sp2 carbon networks inthe graphene sheets. Consequently, the electrical conductivity of the graphene films was greatly improved, from 24 S/cm forRGO films to 200 S/cm after the thermal annealing process. In addition, we have studied the NO2 gas sensing characteristicsof the prepared graphene films.