Reaction Kinetics at the Triple-Phase Boundary in PEM Fuel Cells
Bibliographic record
Abstract
A mathematical model is developed to describe the reaction dynamics in the vicinity of the triple-phase boundary (TPB), which is an important part of the pore scale structure of the catalyst layer in proton exchange membrane fuel cells. The model incorporates coupled diffusion, migration, and reaction phenomena of the chemical components in an undersaturated air pore and ionomer. One challenging feature of the work is the description of the TPB by a system of nonlinear partial differential equations (PDEs), coupling bulk, and surface-diffusion phenomena, which offers an approach to study the rarely investigated proton surface diffusion along the air pore surface. A numerical technique is implemented, taking into account the particular form of the domain, in order to solve the nonlinear PDE system efficiently. Several numerical results are discussed, including a sensitivity analysis with respect to the physical reference case and geometric parameters. The results indicate that surface diffusion might play a major role for the reaction kinetics, but only if the air pore is void of liquid water. In contrast, the formation of liquid water in the gas pores will turn surface diffusion into bulk diffusion, with the latter resembling the Grotthus mechanism.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| 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".