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Effect of Nitrogen Doping and Oxidation of Graphene on the Deposition of Platinum from Trimethyl(methylcyclopentadienyl)platinum(IV)

Summary

Density functional theory evaluates how N doping and oxidation of graphene (via vacancy oxidation) affect vapor-phase trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe\(_3\)) adsorption and dissociation relevant to atomic layer deposition (ALD) of Pt on defective carbon supports. Oxygen incorporation at monovacancies is favorable with and without N dopants, establishing oxidized defect sites as thermodynamically preferred anchors for O. N doping elongates substrate–oxygen bonds, which the authors connect to stronger precursor–substrate interaction on oxidized defective graphene. Nudged elastic band (NEB) calculations report positive reaction and activation enthalpies for elementary MeCpPtMe\(_3\) dissociation steps on the oxidized substrates studied, yet N doping lowers both activation and reaction enthalpies along the sequence and makes chemisorbed MeCpPtMe\(_2\) more favorable. For pyridinic-N-containing models, the overall transformation from MeCpPtMe\(_3\) plus two oxidized monovacancies to MeCpPtMe\(_2\) plus methyl groups bound at those vacancies is exothermic (abstract).

Methods

A — Density functional theory (periodic slabs)

  • Quantum ESPRESSO (PWscf) DFT with dispersion and k-mesh per article; graphene supercells with vacancies, oxygenated defects (epoxide/hydroxyl patterns), and pyridinic / graphitic N substitutions.

B — Nudged elastic band (NEB)

  • NEB paths for MeCpPtMe\(_3\) dissociation and methyl transfer to surface O sites—ALD-relevant coordinates.

C — Analysis

  • Reaction and activation enthalpies; C–O bond lengths vs N doping; compare N-free vs N-doped oxidized vacancy models.

D — Experiments

  • None; static 0 K enthalpy survey for ALD precursor–substrate chemistry.

Static QM (DFT-only) spine: Program: Quantum ESPRESSO PWscf. Functional / dispersion: PBE-family DFT with dispersion corrections and Monkhorst–Pack k-mesh / Γ-centered Brillouin sampling as in J. Phys. Chem. C Methods (k-point density tabulated in the PDF). Basis: plane-wave PAW/pseudopotential treatment. Structures / pathways: periodic graphene slabs with vacancies, O-functionalized defects, and pyridinic/graphitic N; NEB reaction paths for MeCpPtMe\(_3\) elementary steps. Properties compared: 0 K reaction and activation enthalpies, barrier heights along NEB, bond lengths—full convergence settings in the PDF.

Findings

  • Oxidized vacancies are stabilized by O incorporation; N dopants alter substrate–O bonding distances and strengthen MeCpPtMe\(_3\) coupling to oxidized defects relative to selected reference models.
  • NEB: elementary steps can remain barrier-limited with positive enthalpies, but N doping reduces activation and reaction enthalpies for key precursor steps and favors MeCpPtMe\(_2\) formation on the oxidized defective surfaces examined.
  • For pyridinic-N-containing models, the net reaction described in the abstract is exothermic, whereas graphitic-N and N-free cases show different thermodynamic favorability (see article for site-by-site comparison). Comparisons / sensitivity: site-by-site N coordination and defect oxidation pattern change barrier and driving force trends; experimental ALD not in this DFT paper. Limitations / outlook: 0 K static picture; finite-temperature and solvent omitted—see authored caveats in the full text. Corpus / KB: enthalpy values and NEB images must be taken from the version-of-record PDF/SI, not this summary alone.

Limitations

Periodic DFT omits explicit solvent and finite-temperature entropic contributions important for ALD partial pressures; experimental ALD windows require validation beyond 0 K enthalpy trends alone. Dispersion correction choices and supercell sizes follow the J. Phys. Chem. C computational section.

Relevance to group

van Duin co-authorship connects to broader catalytic carbon / ALD interface work; methodologically this entry is DFT + NEB, not ReaxFF.

Citations and evidence anchors

Reader notes (navigation)

For ALD process windows, pair this DFT/NEB page with experimental deposition papers: the J. Phys. Chem. C study supplies 0 K enthalpy trends on defective graphene, not finite-pressure precursor fluxes or surface coverage kinetics measured in reactors.