Oxygen Reduction Reaction Mechanism on PrSrCo<sub>2–<i>x</i></sub>Fe<sub><i>x</i></sub>O<sub>5+d</sub> (<i>x</i> = 0, 1, 2) and Sm<sub>0.2</sub>Ce<sub>0.8</sub>O<sub>1.9</sub> Composite Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells
Bibliographic record
Abstract
Perovskite-type mixed ionic and electronic conductors are finding applications in intermediate-temperature solid oxide fuel cells. Here, we study the effects of substituting Co with Fe on the crystal structure and electrical and electrochemical properties of PrSrCo 2– x Fe x O 5+d (PSCF, x = 0, 1, 2). The electrochemical performance of symmetrical half-cells of PrSrCo 2– x Fe x O 5+d and Sm 0.2 Ce 0.8 O 1.9 composite cathodes with the Sm 0.2 Ce 0.8 O 1.9 electrolyte was measured using electrochemical impedance spectroscopy at 600–750 °C. The oxygen reduction reaction (ORR) mechanism was analyzed as a function of temperature and oxygen partial pressure (pO 2 ) using the distribution function of relaxation times (DFRT). The electrical conductivity measurements of the PSCF pellets were in the range of 100–1300 S cm –1 . The PSCF ( x = 1) – Sm 0.2 Ce 0.8 O 1.9 composite cathode yielded the lowest area specific resistance (ASR) value of 0.07 Ω cm 2 at 750 °C for ORR. DFRT and pO 2 studies showed that impedance arcs corresponding to the high frequency could be attributed to the oxygen ion transfer resistance while the medium-low frequency impedance arcs could be correlated with the charge transfer resistance at the cathode/gas interface followed by ion incorporation. This study demonstrates that the partial substitution of Fe on the Co site improves the ORR activity of PSCF perovskites.
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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 | 0.005 | 0.000 |
| Meta-epidemiology (narrow) | 0.005 | 0.005 |
| Meta-epidemiology (broad) | 0.005 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.001 |
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; both teacher heads agree on what is shown here.
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".