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.

Sn powder as reducing agents and SnO2 precursors for the synthesis of SnO2-reduced graphene oxide hybrid nanoparticles.

A facile approach to prepare SnO2/rGO (reduced graphene oxide) hybrid nanoparticles by a direct redox reaction between graphene oxide (GO) and tin powder was developed. Since no acid was used, it is an environmentally friendly green method. The SnO2/rGO hybrid nanoparticles were characterized by ultraviolet-visible spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The microstructure of the SnO2/rGO was observed with scanning electron microscopy and transmission electron microscopy. The tin powder efficiently reduced GO to rGO, and the Sn was transformed to SnO2 nanoparticles (∼45 nm) that were evenly distributed on the rGO sheets. The SnO2/rGO hybrid nanoparticles were then coated on an interdigital electrode to fabricate a humidity sensor, which have an especially good linear impedance response from 11% to 85% relative humidity.