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Oxidation and hydrogenation of monolayer MoS2 with compositing agent under environmental exposure: ReaxFF Mo/Ti/Au/O/S/H force field development and applications

Summary

This entry mirrors 2022mao-venue-fnano-2022-1034795 (same DOI and scientific content) but ingests the Frontiers galley PDF (papers/Mao_MoS2_TiO2_Frontiers_Nano_2022_galley.pdf) with extraction_quality: partial. Prefer the VOR page for figures and SI cross-references unless you specifically need this file’s provenance.

The article develops a Mo/Ti/Au/O/S/H ReaxFF and applies AMS reactive MD to monolayer MoS\(_2\) oxidation and hydrogenation with Ti clusters under O\(_2\) / H\(_2\)O (and related) environments, including high-temperature ramps used to access reaction pathways on MD time scales. This slug exists to preserve manifest provenance for the galley bytes while keeping the scientific narrative aligned with the Frontiers version-of-record page.

Methods

Canonical curation and PDF: use 2022mao-venue-fnano-2022-1034795 for the full Methods/Results and version-of-record pagination. This slug’s pdf_path is the Frontiers galley papers/Mao_MoS2_TiO2_Frontiers_Nano_2022_galley.pdf (extraction_quality: partial); copy all numerical settings from the VOR/DOI PDF, not the galley alone.

1 — MD application (atomistic dynamics). The article uses ReaxFF-based reactive MD in LAMMPS-class / AMS-annotated workflows (exact program strings in the VOR) on monolayer MoS\(_2\) (pristine and defective), with or without a Ti\(_{20}\) cluster and with O\(_2\) / H\(_2\) and H\(_2\)O-relevant environments at elevated reactant density to access chemistry on nanosecond time scales. 3D PBC on the in-plane supercell; confirm the Z dimension / vacuum in the VOR. Protocol (recalled from the article curation in this repo): minimization → NVT at 300 K for \(\sim 500\,\text{ps}\) equilibration → heat to 3000 K NVT with \(\Delta t = 0.1\,\text{fs}\); optional \(\sim 1000\,\text{K}\) annealing segments. Thermostat and damping: see VOR. Barostat: N/A in the headline NVT ramp-heavy protocol (re-check VOR if a pressure-coupled segment is reported). Electric field: N/A. Enhanced sampling: N/A (no umbrella/Metadynamics in this note unless the VOR states otherwise). ReaxFF QEq and nonbond cutoff policy per the Frontiers Methods. Post-process with VMD/OVITO; bond/fragment ID cutoffs (e.g. Mo–S \(\sim 3.0\,\)Å) are in the VOR and are not re-stated here for this partial galley ingest.

2 — Force-field training. A new Mo/Ti/Au/O/S/H ReaxFF line (DFT/DFTB training set, optimization, element scope) is on the VOR page; this duplicate slug does not duplicate the fit tables.

3 — Static QM / DFT (parametrization). DFT/DFTB benchmarks for ReaxFF fitting are documented on the VOR; this galley manifest note does not expand them.

4 — Experiments. N/A — computational work with device-processing motivation in the VOR.

Findings

Outcomes and mechanisms. Simulations report temperature-dependent oxidation/hydrogenation sequences: S removal, O incorporation, and Ti–O/S interactions that compete with MoS\(_2\) degradation; Ti\(_{20}\) clusters mediate O transfer and local reconstruction relative to pristine MoS\(_2\) under the same thermal ramps. Quantitative barriers and full reaction networks should be read from the VOR/SI—this galley ingest is not a substitute for the typeset PDF. Treat \(\sim 3000\,\)K) NVT \(\Delta t=0.1\,\)fs) windows as deliberately aggressive rare-event sampling, not literal ambient-device oxidation kinetics (see ## Limitations).

Comparisons and levers. Pristine vs defective MoS\(_2\); with vs without Ti\(_{20}\); gas composition, density, and thermal ramps in the VOR. Quantitative barriers and full reaction graphs are read from the VOR/SI, not this galley file.

Limitations

Proof-stage PDF; extreme heating rates and small system sizes probe pathways relevant to high-temperature oxidation rather than ambient kinetics directly. This slug preserves manifest linkage to papers/Mao_MoS2_TiO2_Frontiers_Nano_2022_galley.pdf; narrative figures, timestep tables, and QM benchmarks should be taken from [[2022mao-venue-fnano-2022-1034795]] or the DOI landing page when pagination matters for citations.

Relevance to group

Core van Duin-group ReaxFF development for TMD tribology/chemistry with explicit Ti/Au additives.

Citations and evidence anchors

Reader notes (navigation)