Facile synthesis of soluble functional graphene by reduction of graphene oxide via acetylacetone and its adsorption of heavy metal ions

Abstract

The synthesis of graphene (GR) from graphene oxide (GO) typically involves harmful chemical reducing agents that are undesirable for most practical applications. Here we report a green and facile synthesis method for the synthesis of GR that is soluble in water and organic solvents and that includes the additional benefit of adsorption of heavy metal ions. Acetylacetone, as both a reducing agent and a stabilizer, was used to prepare soluble GR from GO. Transmission electron microscopy and atomic force microscopy provide clear evidence for the formation of few-layer GR. The results from Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy show that reduction of GO to GR has occurred. Raman spectroscopy and X-ray photoelectron spectroscopy also indicate the removal of oxygen-containing functional groups from GO, resulting in the formation of GR. The results of dispersion experiments show that GR can be highly dispersed in water and N,N-Dimethylformamide. The reaction mechanism for acetylacetone reduction of exfoliated GO was also proposed. This method is a facile and environmentally friendly approach to the synthesis of GR and opens up new possibilities for preparing GR and GR-based nanomaterials for large-scale applications. Of even greater interest is that inductively coupled plasma atomic emission spectroscopy suggests that synthesized GR may be applied in the absorption of Cd2+ and Co2+ due to the strong coordination capacity of acetylacetone on the surfaces and edges of GR and the large surface area of GR in aqueous solutions. The maximum adsorptions are 49.28 mg g−1 for Cd2+, which is 4.5 times higher than that of carbon nanotubes, and 27.78 mg g−1 for Co2+, which is 3.6 times higher than that of titania beans.