† Electronic supplementary information (ESI) available: Experimental preparation and instrumentation, XRD patterns and Raman spectra of graphite and GO, full XPS spectra of GO and ED-RGO, photographs of filtrates after adsorptions, and SEM-EDX images of ED-RGO before and after Cr(VI) adsorption. See

No abstract

We demonstrate a facile and environmentally friendly approach to prepare well-dispersed graphene sheets by g-ray induced reduction of a graphene oxide (GO) suspension in N,N-dimethyl formamide (DMF) at room temperature. GO is reduced by the electrons generated from the radiolysis of DMF under g-ray irradiation. The reduced GO by g-ray irradiation (G-RGO) can be re-dispersed in many organic solvents, and the resulting suspensions are stable for two weeks due to the stabilization of N(CH 3 ) 2 + groups on G-RGO. Additionally, G-RGO is efficient in improving the conductivity of polystyrene (PS). Its PS nanocomposites exhibit a sharp transition from electrically insulating to conducting with a low percolation threshold of 0.24 vol% and a high electrical conductivity of 45 S m À1 is obtained with only 2.3 vol% of G-RGO. The superior electrical conductivity is attributed to the uniform dispersion of the G-RGO sheets in the PS matrix.