Structural and Electrochemical Characterization of Metastable PtAu Bulk and Surface Alloys Prepared by Crossed-Beam Pulsed Laser Deposition
Bibliographic record
Abstract
Crossed-beam pulsed laser deposition in a moderate He background gas pressure was used to prepare PtAu thin films. The Pt bulk content was determined by neutron activation analysis, whereas X-ray diffraction and X-ray photoelectron spectroscopy were used to assess the bulk and the surface structure of the films, respectively. It is shown that metastable PtAu alloys with a unique fcc structure are formed over the whole composition range. The surface composition of the films closely follows the bulk content, and X-ray photoelectron spectroscopy reveals that the surface of the films is also made of a PtAu alloy. These films are stable under ambient conditions. The electrochemical properties of these films were determined by cyclic voltammetry in H 2 SO 4 electrolyte, and their reactivity toward the electrooxidation of CO and the electroreduction of O 2 was assessed. The CO stripping peak potential value increases with the Au content, indicating an increased binding energy in comparison with polycrystalline Pt. Similarly, there is a cathodic shift of the Pt oxide reduction peak for the Au-rich alloy that indicates stronger Pt−O binding energies as compared with Pt-rich alloy electrodes. At the surface, the presence of Au in close proximity to Pt atoms induces a shift of the d-band center of the Pt atoms that translates into stronger bonds with CO- and O-containing species at the surface of the samples. As far as we can tell, the surface composition and structure of the deposits are not modified following the electrochemical measurements.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".