Electron-Irradiated GO and rGO for Scalable Solid-State Hydrogen Storage

Motivation

Hydrogen carries roughly three times the energy of gasoline per kilogram and burns clean at the point of use, but storage remains the bottleneck. Compressed gas requires 700 bar, liquid hydrogen requires cryogenic temperatures near −253 °C, and engineered sorbents such as MOFs are too expensive to deploy at scale. The Perez group had previously shown that low-energy electron irradiation hydrogenates pristine CVD graphene, including suspended graphene drums, by dissociating adsorbed water and bonding the resulting hydrogen to the lattice. Pristine flakes cannot scale. Graphene oxide (GO) and reduced graphene oxide (rGO) share the same carbon backbone while being bulk-producible and storable as dry nanopowders, so this project asked whether the same electron-induced mechanism transfers to them. No prior study had attempted electron-induced hydrogenation of these scalable graphene derivatives.

Methods

GO and rGO samples were irradiated in ultra-high vacuum with a 1.5 keV electron beam at a fluence of 3×10¹⁶ e⁻/cm². The proposed mechanism is electron-impact dissociation of adsorbed water and surface species: hydrogen radicals bond to the carbon lattice, converting sp² carbon toward sp³, while oxygen-containing functional groups are removed. Four independent characterization techniques tracked the changes: Raman spectroscopy (the D′−G_app separation and the I_D/I_D′ ratio), X-ray photoelectron spectroscopy (C 1s deconvolution), temperature-programmed desorption (TPD), and Hall measurements.

Results

The four techniques converge on simultaneous reduction and hydrogenation. Raman D′−G_app increased at every tested point, consistent with oxygen-group removal, while I_D/I_D′ rose, indicating growing sp³ adsorbate character even as functional groups were stripped. XPS quantified both halves of the story: C−O bonding fell by roughly 43 percent, while C−H bonding rose by roughly 27 percent in GO and 7 percent in rGO. Hall measurements showed resistivity falling 54 percent and mobility rising 142 percent, the opposite of what random beam damage would produce, which rules out simple amorphization. TPD performed immediately after irradiation showed H₂ desorbing in the temperature range characteristic of C−H bond dissociation, and a second ramp showed nothing, confirming the hydrogen originated inside the irradiated sample rather than from chamber background.

Dissemination

This work produced my first conference talk, at the APS TAO unit meeting in fall 2025, and was subsequently presented as a first-author contributed talk at the APS Global Physics Summit in Denver (March 2026), at UT Energy Week, and at the Texas Science and Engineering Fair. With Jian Park, I presented the project at Regeneron ISEF 2026 in the Physics and Astronomy category. It also anchored a 2026 UNT Scholars Day keynote recapping the lab’s carbon-hydrogenation arc.

Current status and future work

Complete as a standalone study. Its stated limitation is that absolute hydrogen yield was never quantified; calibrated TPD across irradiation dosages, benchmarked against the DOE 6.5 wt% target, is the natural next measurement. In practice the arc continued by extending the same irradiation-and-characterization program to HiPco single-walled carbon nanotubes, which became its own project below, and a dose-dependent sp³ saturation comparison across SWCNTs, GO, and rGO remains an open experiment the lab is positioned to run.