Few-layer graphene-like flakes derived by plasma treatment: A potential material for hydrogen adsorption and storage

• Few-layer graphene-like flakes were prepared by plasma-processing of natural graphite.
• Demonstrated large surface areas (up to 800 m2/g) and nanopore sizes (below 0.8 nm).
• Characterization was performed using SEM, TEM, XPS, XRD and N2 porosimetry methods.
• H2 storage behavior was evaluated by adsorption/desorption at 77 K and up to 100 bar.
• Reversible H2 adsorption isotherms with maximum uptake of up to ∼2 wt.% at ∼60 bar.

A novel, one-step, wet-free, environmental friendly and high-yield method for producing few-layer graphene powders with large surface areas (up to 800 m2/g) and narrow nanopore sizes (0.7–0.8 nm) using plasma-induced exfoliation of natural graphite is presented. Advanced characterization techniques were employed, including scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and N2 gas adsorption/desorption measurements at 77 K, to investigate the morphological, elemental, structural and textural/porosity properties of these nanomaterials. Fully reversible H2 gas adsorption/desorption isotherms with maximum gravimetric capacities of up to ∼2 wt.% at 77 K and ∼60 bar are reported here. The H2 storage performance at 77 K is well correlated with certain textural features such as specific surface area and microporosity. The results of this work provide a valuable feedback for further research on plasma-processed graphene-based materials towards efficient H2 storage via cryo-adsorption.

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