Hydrogen-rich water for green reduction of graphene oxide suspensions

H-2-rich water as a green antioxidant was applied for deoxygenation of graphene oxide (GO) suspensions. The ability of H-2-rich water for deoxygenation of GO sheets was found comparable to the ability of hydrazine (as a standard and powerful reductant), using X-ray photoelectron spectroscopy. In fact, the O/C ratio of GO sheets could be reduced from 0.51 to 0.21 and 0.16 by H-2-rich water and hydrazine, respectively. More importantly, while C-N bond formation is one of the side effects of GO reduction by hydrazine, no chemical C-N bond was found on the H-2-water-reduced GO (rGO) sheets. This also resulted in a better restoration of the graphitic structure of the H-2-water-rGO, as confirmed by Raman spectroscopy. Although H-2-rich water exhibited slightly lower deoxygenation efficiency than hydrazine, the absence of any C-N bond on the H-2-water-rGO resulted in an excellent electrical conductivity (corresponding to the sharp reduction in the electrical sheet resistance (Rs) of the GO sheets from -6.3 x 10(10) to 7.2 x 10(5) Omega/sq) which is comparable with the typical conductivity of hydrazine-rGO sheets (here, with Rs value of similar to 4.4 x 10(5) Omega/sq). These results suggest application of H-2-rich water as an effective substitute for hydrazine in environment-friendly and mass production of rGO sheets. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.