Hydrogen uptake of thermally and chemically modulated graphene oxide

M.S.L. Hudson, O.N. Srivastava, S. Simizu, S.G. Sankar
Central University of Tamil Nadu, IN

Keywords: helium isotherm, nitrogen isotherm, thermal reduction, chemical reduction, pore size analysis

Summary:

Here, we present the high pressure hydrogen sorption isotherm up to 50 bar of modulated graphene oxide (GO) by thermal reduction (TR-GO), chemical reduction (CR-GO) and decoration with Fe nanoclusters (Fe-GS). GO was first derived by thermal exfoliation of graphite oxide, prepared by modified Standermiur method; further reduction at 623K under high vacuum yields TR-GO. CR-GO has been produced by reduction of GO using hydrazine. Fe-GS has been synthesized through arc discharge between the ends of two graphite rods with one rod carrying Fe nanoparticles. The surface areas of these graphene samples were determined from the nitrogen adsorption isotherm employing Brunauer, Emmett and Teller (BET) method. The Dubinin-Radushkevich (D-R), Dubini-Astakhov (D-A) isotherm and Kelvin's equation were used to determine the pore size and pore volume. Hydrogen Pressure Composition Isotherms (PCI) were determined at 300 K and 77 K, between 0.1 and 50 bar. The surface area calculated from nitrogen adsorption isotherm at 77 K using BET method for GO, TR-GO, CR-GO and Fe-GS are 304, 357, 90 and 185 m2g-1, respectively. Fe-GS exhibit the maximum hydrogen uptake capacity of over 2 wt.%.