Proton transport through one-atom-thick crystals

Evidence and attribution¶

Authority of statements

Prose below summarizes the publication identified by doi, title, and pdf_path in the front matter. For definitive numerical values and figures, use the peer-reviewed article.

Summary¶

Electrical transport through micromembranes separates proton-injecting Nafion/PdHₓ stacks with suspended monolayer graphene, hexagonal BN, or MoS₂ barriers in humid hydrogen/argon. Monolayer graphene and hBN show measurable proton conductance under ambient conditions, whereas monolayer MoS₂, bilayer graphene, and few-layer hBN do not within the same protocol. Monolayer hBN exhibits the highest room-temperature proton conductance in the study, with a low activation energy ~0.3 eV reported for that barrier; graphene’s areal resistivity is estimated to fall below ~10⁻³ Ω cm² above ~250 °C. Catalytic metal decoration enhances throughput. Results position atomically thin crystals as selectively proton-conducting versus heavier species (abstract; extract pages 1–2).

Methods¶

Sample fabrication (2D membranes)¶

Micromechanically cleaved graphene, hBN, and MoS\(_2\) flakes are transferred and suspended over micrometre-scale apertures in Si substrates; samples are screened to minimize pinholes before measurement (Letter; extract).

Proton-injection contacts and electrolyte environment¶

Membranes are coated on both sides with Nafion and electrically contacted using PdH\(_x\) stacks that inject protons into the measurement path (extract).
Gas-phase measurements use H₂/Ar mixtures at 100% relative humidity; Extended Data includes a liquid HCl control reporting consistent conductivities (extract).

Transport measurements¶

Current–voltage (I–V) sweeps quantify proton conductance through the suspended 2D films, comparing monolayer vs few-layer stacks (bilayer graphene, few-layer hBN, monolayer MoS\(_2\), etc.) (extract).

Analysis metrics¶

Arrhenius activation energies and areal resistivity estimates are extracted from temperature-dependent datasets as reported in the Letter (numbers in Summary above).

Atomistic simulation and electronic-structure protocols¶

N/A — atomistic MD / DFT production: the Letter summarized here reports electrical transport through micromembranes with gas-phase H₂/Ar humidity control and I–V characterization, not LAMMPS-class trajectories or plane-wave DFT workflows. Timestep, thermostat, and PBC items from the MD-application checklist therefore do not apply to the primary evidence chain in papers/Others/Nature_graphene_protons_I.pdf (corroborate any secondary modeling citations in the full PDF if present).

Findings¶

Monolayer graphene and monolayer hBN show measurable proton conduction under ambient conditions, whereas no proton current is resolved through monolayer MoS\(_2\), bilayer graphene, or thicker hBN within the same protocol (parasitic leakage discussed). Monolayer hBN exhibits the highest room-temperature proton conductance among the barriers tested; the Letter reports a low activation energy of ~0.3 eV for monolayer hBN and estimates graphene’s areal resistivity falls below ~10⁻³ Ω cm² above ~250 °C. Catalytic metal decoration increases proton throughput. The discussion ties differences in permeation to integrated valence electron density patterns for graphene versus hBN versus the thicker MoS\(_2\) stack (Letter; extract pages 1–2).

Limitations¶

Device architecture relies on Nafion-mediated proton supply; interpretation connects macroscopic currents to monolayer barrier physics as detailed in the full Methods.

Citations and evidence anchors¶

DOI 10.1038/nature14015 (extract header).
Abstract-level claims (extract pages 1–2).

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graphene-nanocarbon