The critical role of bulk density of graphene oxide in tuning its defect concentration through microwave-driven annealing

摘要

cqvip:Controlling the concentration of defects in reduced graphene oxide(rGO)to tailor its electrical and physicochemical properties has remained a significant challenge.We report that extent of microwave(MW)-driven annealing of rGO is influenced significantly by its bulk density,which allows us to vary its defect density and crystallite size over wide ranges by controlling this parameter.Extent of annealing was investigated by multiple techniques including Raman and X-ray photoelectron spectroscopies,and electrical conductivity measurements.Improved corrosion resistance of rGOs upon annealing was examined by cyclic voltammetry in H_2SO_4electrolyte and temperature-programmed oxidation of rGO.Our results indicate that a low bulk density of r GO facilitates defect annealing,yielding high-quality carbon with 99.3 wt%purity,oxidative resistance as high as graphite powder,and an electrical conductivity of36,000 S m^(–1)in the compressed powder form.These results demonstrate a prospective synthesis route for tailor-made nanocarbons from rGO through MW-driven annealing.