Ultrafine jagged platinum nanowires enable ultrahigh mass activity for the oxygen reduction reaction
Summary¶
This Science report presents ultrafine jagged platinum nanowires (J-PtNWs) as electrocatalysts for the acid oxygen reduction reaction (ORR) with exceptionally high mass activity and electrochemically active surface area (ECSA) relative to conventional Pt/C benchmarks. The jagged morphology is argued to expose a high density of under-coordinated / high-index-like Pt sites while maintaining favorable surface-area-to-mass ratio compared with bulkier nanoparticle morphologies. The work integrates solution synthesis of Pt/NiO core/shell nanowires, thermal annealing to PtNi alloy wires, electrochemical dealloying to pure jagged Pt, microscopy, electrochemistry, and reactive molecular dynamics (Caltech co-authors) used to relate highly stressed, rhombohedral-rich, under-coordinated surface motifs to ORR activity (Science text).
The abstract highlights ORR performance metrics at 0.9 V vs RHE, including specific activity and ECSA values that combine to a mass activity substantially above commercial Pt/C and prior record catalysts cited in the article.
Methods¶
Synthesis, microscopy, and electrochemistry: Pt/NiO core/shell nanowires are grown from Pt(acac)\(_2\) and Ni(acac)\(_2\) in 1-octadecene with oleylamine. TEM shows core/shell contrast with typical diameters ~5 nm or less and lengths ~250–300 nm; HRTEM resolves NiO (111) shell fringes (~0.24 nm) and Pt (111) in the core (~0.23 nm). Annealing in Ar/H\(_2\) (97/3) at 450 °C converts the wires to uniform PtNi alloy while preserving overall morphology; EDS gives Pt/Ni ~15/85 before and after annealing. Electrochemical dealloying leaches Ni to yield jagged Pt nanowires. ORR is evaluated at 0.9 V vs RHE as in Findings.
MD application (supporting atomistic modeling): The article cites reactive molecular dynamics to argue that highly stressed, rhombohedral-rich, under-coordinated surface motifs on jagged wires favor ORR relative to more relaxed surfaces. Code, timestep, ensemble, thermostat/barostat, system size, trajectory length, and electrostatic settings for those runs: N/A — not given in the corpus text slice used here; see the Science article and SI for full simulation metadata.
Force-field training: N/A — not a force-field fitting paper.
Static QM / DFT: This page’s indexed text centers on synthesis, microscopy, electrochemistry, and supporting reactive MD; any standalone periodic DFT benchmarks in the full article are not transcribed here. DFT functional / hybrid level: N/A — not stated in the indexed extract. Dispersion correction (DFT-D / vdW): N/A — not stated in the indexed extract. Basis set or plane-wave / PAW settings: N/A — not stated in the indexed extract. k-point / k-mesh sampling: N/A — not stated in the indexed extract for any periodic QM tables. Structures / pathways (QM): N/A — not summarized here beyond the experimental nanowire narrative. QM properties tabulated (energies, barriers, DOS, …): N/A — see Science/SI if the full paper reports them.
Findings¶
At 0.9 V vs RHE, the authors report specific activity ~11.5 mA/cm², ECSA ~118 m²/g Pt, and mass activity ~13.6 A/mg Pt—about 50× the mass activity of commercial Pt/C cited as state of the art and nearly twice prior record values (6.98 A/mg Pt and 5.7 A/mg Pt references in the abstract). The jagged morphology is linked to high surface-area-to-mass and under-coordinated, rhombohedral-rich surface character. Reactive MD supports the qualitative picture that stressed surfaces on these wires outperform relaxed ones; quantitative MD-derived barriers or coordination statistics are not summarized on this page—use SI with the PDF.
Limitations¶
This is primarily an experimental catalysis paper; MD/DFT details are supporting evidence. Durability under fuel-cell load cycles, ionomer effects, and operando restructuring extend beyond the abstract claims. Reactive MD parameters and DFT functionals have known approximations for electrified interfaces.
Relevance to group¶
Caltech Goddard collaboration thread on electrocatalysis with atomistic modeling—adjacent to fuel-cell and battery-interface literature in the broader corpus, though not a ReaxFF parameterization paper.
Citations and evidence anchors¶
- DOI 10.1126/science.aaf9050.
- Excerpt alignment:
normalized/extracts/2016correction-venue-ultrafine-jagged_p1-2.txt.