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Controllable atomistic graphene oxide model and its application in hydrogen sulfide removal

Evidence and attribution

Authority of statements

Sections below summarize the publication identified by doi, title, and pdf_path in the front matter. The corpus PDF includes AIP boilerplate pages; extraction_quality remains partial until a clean extract is regenerated.

Summary

Uses temperature-programmed MD with ReaxFF to generate atomistic graphene oxide (GO) models by grafting epoxy and hydroxyl groups with tunable concentrations, aiming to match experimental structural fingerprints and selected QM benchmarks. The constructed models are then used for reactive adsorption simulations of H₂S, including H₂O/H₂S mixtures, interpreting dissociation at carbonyl-class sites and release of H₂O, CO₂, and CO as chemistry progresses. Water is found to compete for carbonyl sites, suppressing H₂S reactivity in mixtures—consistent with the authors’ experimental comparison.

Methods

1 — MD application (papers/Huang_GrapOxide_H2S_JCP2013.pdf; abstract + intro in normalized/extracts/2013huang-venue-paper-3_p1-2.txt). Engine / code: Reactive molecular dynamics with ReaxFF in LAMMPS as stated in the article body summarized on this page. System size & composition: Graphene sheets are oxidized by grafting epoxy and hydroxyl groups with tunable composition to build GO supercells containing many carbon atoms plus oxygen/hydrogen; exact counts per realization are in the PDF Methods (not on the short extract). H₂S and H₂O/H₂S runs use the generated GO slabs with adsorbates as specified there. Boundaries / periodicity: three-dimensional periodic boundary conditions (PBC) / in-plane periodicity as standard for the LAMMPS cells described in the article (confirm non-periodic variants, if any, in PDF). Ensemble: NVT for both the temperature-programmed construction stage (300–2300 K ramp at 0.005 K/iteration) and the 300 K H₂S production segments. Timestep: 0.25 fs (velocity Verlet) for the 200 ps H₂S window quoted in prior curation (verify in PDF). Duration / stages: temperature-programmed anneal for GO build; 200 ps reactive sampling for H₂S/mixture cases (plus any equilibration legs tabulated in Methods). Thermostat: Berendsen with τ = 100 fs for the 300 K H₂S protocol as stated in the article. Barostat: N/A — constant-volume NVT legs summarized here. Pressure: N/A — no NPT hydrostatic pressure target stated for these cells on the indexed excerpt. Electric field: N/A. Replica / enhanced sampling: N/A. Connectivity tracking: bond-order criterion at 20% of equilibrium bond length (article Methods).

2 — Force-field training. N/A as a standalone new fit: the work applies published ReaxFF chemistry while benchmarking motifs with DFT where the article specifies.

3 — Static QM. DFT checks on selected GO motifs as cited against QM references in the article (functional/basis details in PDF).

Findings

Outcomes & mechanisms: H₂S dissociates at carbonyl-class oxygen sites on the modeled GO, releasing H₂O, CO₂, and CO as reaction products in the ReaxFF trajectories summarized by the authors. In H₂O/H₂S mixtures, H₂O preferentially adsorbs to carbonyl sites and blocks H₂S access to those reactive sites.

Comparisons: Abstract states agreement between calculation and experiment for mixture trends on GO materials studied.

Sensitivity / design levers: Temperature-programmed construction tunes epoxy/hydroxyl concentrations and defect content; H₂O/H₂S concentration controls competitive adsorption at carbonyl sites.

Limitations & outlook: Amorphous GO realizations are non-unique; longer production runs and broader composition sweeps may be needed for quantitative sorption isotherms—see authored caveats in the PDF.

Corpus honesty: extraction_quality: partial for this slug; this page is grounded in pdf_path, the DOI abstract/intro extract, and the Methods bullets already published in the wiki—confirm every numerical protocol line against papers/Huang_GrapOxide_H2S_JCP2013.pdf.

Limitations

GO structural disorder is vast; any single atomistic realization is illustrative. Quantitative sorption isotherms require longer sampling and broader composition sweeps. Where extraction_quality is partial, the tracked PDF and DOI remain the quantitative authority over short local extracts.

Relevance to group

van Duin co-authorship on ReaxFF for functionalized graphene in environmental sulfide chemistry.

Citations and evidence anchors

  • Abstract and Sec. 1: GO model + H₂S chemistry claims (J. Chem. Phys. 139, 194707 (2013); DOI above).