Aspects of the Chemical Degradation of PFSA Ionomers used in PEM Fuel Cells
Bibliographic record
Abstract
Abstract The chemical degradation of perfluorosulfonic acid (PFSA) membranes was studied both in‐situ (during fuel cell operation) and ex‐situ (by Fenton's test). During fuel cell operation, the degradation rate was quantified by monitoring the rate of fluoride release. The rate of degradation was found to be strongly dependent on operating conditions. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) were used to identify degradation products other than fluoride generated during fuel cell operation. Strong similarities were found between the organic fragments generated from both the in‐situ (fuel cell operation) and ex‐situ (Fenton's test) degradation processes. The chemical structure of the fragment is consistent with that of the side chain on the PFSA ionomer used in the experiments. The implications of the existence of this product for the chemical degradation mechanism are discussed.
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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 | 0.001 |
| 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 | 0.001 | 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 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".