Electron Irradiation and Raman Characterization of Reduced Graphene Oxide Film

Graphene is a viable storage vehicle for hydrogen, possibly hydrogenated through electron irradiation. Current research has primarily focused on graphene in the form of crystalline flakes, but graphene’s feasibility for hydrogen storage hinges on its availability in an accessible form. Thus, we are investigating whether the electron irradiation of reduced graphene oxide (rGO) powder, a more accessible form of the material, can reach the same end of hydrogenation. Samples consisted of rGO powder combined with deionized water and turned into a homogenous film using a mortar and pestle. This film was then deposited onto a 2.25 cm² SiO2 wafer, which was irradiated by electrons in ultra-high vacuum to a dosage of 3x10¹⁶ e^-/cm2. Raman spectra were acquired before and after irradiation, and deconvolved into D, G, and D’ peaks. Deconvolution shows that electron irradiation increases both the center difference D’ - G_app and I_D/I_D’ height ratio. The increase in D’ - G_app is consistent with a decrease in oxygen domains, but the increased I_D/I_D’ correlates to increase in sp³ character among remaining defects, suggesting the overall addition of sp³ defects (possibly hydrogen absorbates), proving promising for rGO’s use in industrial hydrogen storage. Further studies to confirm the presence of hydrogen defects can consist of thermal annealing of irradiated samples, along with mass spectrometry to confirm the identity of the adsorbates released.