Non-Noble Electrocatalysts for O<sub>2</sub> Reduction: How Does Heat Treatment Affect Their Activity and Structure? Part II. Structural Changes Observed by Electron Microscopy, Raman, and Mass Spectroscopy
Bibliographic record
Abstract
In part I of this paper, a model was proposed to (i) describe the gasification of a spherical carbon black particle by ammonia at high temperature and (ii) explain the activity for the O 2 electroreduction of catalysts based on Fe and carbon heat-treated in NH 3 . In this second part, such catalysts, heat-treated for various times in ammonia, are characterized by electron microscopy, Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Electron microscopy shows an average particle diameter of 38 nm for the pristine furnace black, decreasing to 28 nm after the carbon powder loses 90% of its mass. This agrees with model prediction. Raman spectroscopy shows that the experimental width at half-maximum of both the graphitic peak (∼1595−1600 cm -1 ) and the disorder and graphitic-edge peak (∼1345−1355 cm -1 ) constantly decreases with increasing weight loss. It is found that the width at half-maximum of these peaks correlates with the fraction of disordered carbon phase calculated by the model. Last, changes of the ToF-SIMS total and Fe + signals upon gasification of the carbon black also support the model.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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 teacher head, 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".