Non-PGM Electrocatalysts for PEM Fuel Cells: Thermodynamic Stability of Potential ORR CoNx-C Electrocatalytic Sites
Bibliographic record
Abstract
We present here a thermodynamic assessment of the stability behavior in acidic environments at 298 and 353 K (80 °C) of several Co-based sites that may potentially be active for the oxygen reduction reaction (ORR) at the cathode of proton exchange membrane (PEM) fuel cells. These sites are: i) the porphyrin-like CoN4/C site located in a micropore, ii) two different 1,10-phenanthroline-like CoN(2+2)/C sites located either in a micropore or embedded into a graphene sheet, and iii) the CoN(4+2)/C site having (at its center) the structural motif of the hexa-aza-macrocyclic complex of Co(II) embedded into a graphene sheet. The calculations of the equilibrium constants ( K c ) for the reactions of demetallation indicate that all evaluated active sites are chemically stable in an acidic medium at both 298 and 353 K. At 298 K, K c values for CoN4/C and for the two examples of CoN(2+2)/C sites are very similar. The same conclusion is also true at 353 K. However, the simple introduction of two supplementary nitrogen atoms in the structure of the embedded hexa-aza CoN(4+2)/C site vs that of the embedded phenanthroline-like CoN(2+2)/C site significantly affects its stability toward Co2+ demetallation, rendering CoN(4+2)/C much less likely to demetallate than CoN(2+2)/C either at 298 or 353 K.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.002 | 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".