Abstract
In this research, a highly conductive graphene film was synthesized through the chemical reduction of graphene oxide (RGO) nanosheets followed by thermal treatment at 1100℃ (RGO-1100℃) under H2 ambient. The as-prepared graphene films were characterized by using X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, X-ray diffractions, raman spectroscopy, transmission electron microscopy, scanning electron microscopy, atomic force microscopy and by electrical conductivity measurements. The results showed that the thermal treatment efficiently removed residual oxygen-containing functional groups on the surface of the RGO sheets and simultaneously restored the sp2 carbon networks in the graphene sheets. As a result, the electrical conductivity of RGO-1100℃ (~210 S/cm) film was greatly improved compared with that of RGO (~24 S/cm) and graphene oxide (4.2 × 10–4 S/m) films. In addition, the NO2 gas sensing characteristics of the as-prepared RGO films were studied. The results indicated that RGO films were highly responsive to NO2 at temperature of 200℃.
Highlights
Graphene, a single layer of sp2-hybridized carbon atoms in a hexagonal two-dimensional lattice, has attractedHow to cite this paper: Van Khai, T., Lam, T.D., Van Thu, L. and Kim, H.W. (2015) A Two-Step Method for the Preparation of Highly Conductive Graphene Film and Its Gas-Sensing Property
For reduction of graphene oxide (RGO) sample, the peak disappeared in a region of low angle and another broad peak at 22.19 ̊ corresponding to d-spacing of 4.0 Å appeared
This indicated that a large number of functional groups on the surface of graphene oxide (GO) was removed during chemical reduction process
Summary
A single layer of sp2-hybridized carbon atoms in a hexagonal two-dimensional lattice, has attractedHow to cite this paper: Van Khai, T., Lam, T.D., Van Thu, L. and Kim, H.W. (2015) A Two-Step Method for the Preparation of Highly Conductive Graphene Film and Its Gas-Sensing Property. Chemical reduction of GO is one of the most promising methods to realize low-cost and high-throughput preparation of converted graphene with excellent process ability [12]. The chemically RGO sheets still exhibit much lower conductivity than pristine graphene, mainly due to the presence of irreversible defects, disorder and residual functional groups. It is necessary to develop a more effective reduction method to produce graphene-like film with high electrical conductivity. It is demonstrated that thermal annealing is the most effective method capable of removing oxygen from GO films, where reduction is accomplished by decomposition of oxygen containing groups and simultaneous restoration of sp carbon networks [13]. High-temperature annealing is required to repair the defects and further remove the residual functional groups in RGO sheets to improve its electrical properties
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