Enhanced hydrogen adsorption by Fe3O4-graphene oxide materials

In the present work, graphene oxide (GO) was prepared by hummers method from natural graphite and modified with iron oxide nanoparticles. The structural order and textural properties of the graphene-based materials were studied by TEM, XRD, TG-DTA and FT-IR. Hydrogen adsorption measurements have been carried out at 77 or 87 K, and atmospheric pressure on graphene oxide and Fe3O4-graphene oxide materials. Hydrogen adsorption at 77 K and atmospheric pressure reached values in the order of 1.7 and 2.1 wt% for graphene oxide and Fe3O4-graphene oxide materials, respectively. The hydrogen adsorption capacities of the Fe3O4-graphene oxide materials compare favorably well with those attained with high-value carbon materials. The isosteric heat of adsorption (Q (st)) was investigated as a function of hydrogen uptake at 77 and 87 K over the pressure range of 0 to atmospheric pressure. The isosteric heat of adsorption for magnetic GO (9.7 kJ mol(-1)) was found to be higher than for GO (6.1 kJ mol(-1)).