Graphene oxide reduced and modified by environmentally friendly glycylglycine and its excellent catalytic performance

An environmentally friendly new approach to prepare reduced graphene oxide (RGO) was developed by using glycylglycine (glygly) as both a reducing and stabilizing agent. Graphene oxide (GO) was transformed to RGO with the appropriate pH, temperature and reducing agent/GO ratio. The RGO was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, xray diffraction, xray photoelectron spectroscopy (XPS), and transmission electron microscopy. The RGO aqueous suspension showed extraordinary stability in the absence of any external stabilizing reagents. The XPS analysis showed that this excellent stability is due to modifications of the RGO nanosheets by the glygly molecules. The modified RGO complex with copper shows good catalytic performance for reduction of 4-nitrophenol to 4-aminophenol.