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Reactive molecular simulations of protonation of water clusters and depletion of acidity in H-ZSM-5 zeolite

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Authority of statements

Prose below summarizes the publisher proof extract. For tables, references, and final pagination, use the edited article PDF.

Summary

This wiki slug registers a publisher proof PDF (papers/Joshi_PCCP_2014_Zeolite_protons_proof.pdf) for the same Physical Chemistry Chemical Physics article as 2014joshi-physical-che-reactive-molecular (DOI 10.1039/c4cp02612h). Scientifically, the study uses ReaxFF reactive molecular dynamics with refitted Si/Al/O/H parameters trained against density functional theory to improve water–Brønsted acid site energetics in H-ZSM-5 (MFI). The authors probe adsorption, self-diffusion, and loading-dependent protonation of water, including formation of protonated water clusters at higher water content and rapid proton hopping that relocates charge among acid sites—mechanisms framed as depleting localized acidity in a loading- and temperature-dependent sense. For authoritative pagination, final figure labels, and any editorial corrections, readers should use the version-of-record PDF on the sibling page; this proof ingest exists for corpus provenance and may contain author-query banners.

Methods

This slug registers a publisher proof PDF for the same article as [[2014joshi-physical-che-reactive-molecular]] (DOI 10.1039/c4cp02612h); Methods text should be cited from the version-of-record PDF when possible.

Reactive MD system (H-ZSM-5 + water)

  • ReaxFF RMD in a periodic MFI framework explores water loading and temperature as control variables for adsorption, diffusion, and Brønsted-site proton chemistry (Summary).

Parameter refit against DFT

  • Si/Al/O/H parameters are refit using DFT training data emphasizing acid-site energetics and water–framework interactions relative to an earlier parameter set (Summary).

What this proof PDF is not

  • The proof file may contain layout queries and is not authoritative for final run lengths, cell sizes, or analysis scripts—read [[2014joshi-physical-che-reactive-molecular]] + VOR PDF.

1 — MD application (proof ingest; same study as VOR)

  • Protocol: ReaxFF reactive molecular dynamics on periodic MFI H-ZSM-5 with water loading and temperature as controls (Summary); N/A — engine string/timestep/thermostat law not re-keyed from papers/Joshi_PCCP_2014_Zeolite_protons_proof.pdf here (use [[2014joshi-physical-che-reactive-molecular]]).
  • System size & composition: Zeolite supercell models of H-ZSM-5 with explicit water content as a loading variable (abstract-level description mirrored on the VOR page); exact atom counts are N/A — not re-keyed from the proof PDF here.
  • Boundaries / periodicity: Periodic MFI framework (Summary); N/A — full PBC statement not re-keyed from the proof PDF here.
  • Ensemble: N/A — NVT/NPT choice not re-keyed from the proof PDF here (VOR Methods).
  • Duration / stages: Equilibration and production segment lengths are N/A — not re-keyed from the proof PDF here (VOR Methods).
  • Barostat / hydrostatic pressure: N/A — pressure control not re-keyed from the proof PDF here (typical zeolite adsorption studies are constant-volume; confirm in VOR PDF).
  • Electric field: N/A — not indicated in the abstract-level summary used here.
  • Replica / enhanced sampling: N/A — not indicated in the abstract-level summary used here.

2 — Force-field training (proof ingest)

  • Refit scope: Si/Al/O/H ReaxFF against DFT training data emphasizing acid-site energetics (Summary); N/A — full QM table reproduction omitted on this proof-ingest page.

Findings

The version-of-record abstract and curated summary on [[2014joshi-physical-che-reactive-molecular]] report that the refitted force field yields a water diffusion coefficient in strong agreement with experiment, that higher loading increases the frequency of water protonation and supports larger protonated clusters, and that clusters remain short-lived because protons and water molecules exchange rapidly among clusters while proton-hopping events move protons between distinct Brønsted sites. This proof-ingest page does not independently verify those numerical results against the proof text, which is layout-incomplete by nature.

Limitations

The local pdf_path is a proof with author queries and possible figure placeholder differences relative to the VOR. Use [[2014joshi-physical-che-reactive-molecular]] for stable scholarly citation strings.

For operators automating ingest, note that proof PDFs sometimes contain watermark lines and query sidebars that are not part of the scholarly text; downstream extractors may capture those artifacts, so curated wiki prose should prefer the final PDF when available.

Reader notes (navigation)

Use 2014joshi-physical-che-reactive-molecular (papers/Joshi_PCCP_2014_Zeolite_protons.pdf) for the full article text and citation strings.

Citations and evidence anchors