Complex Impedance Spectroscopy Study of the Thermolysis Products of Metal–Organic Frameworks
Bibliographic record
Abstract
The products of thermal transformation of MOF-253 (Al-containing MOF) and its Pt-based derivative, into carbon-black-based electrocatalyst were studied using ac impedance spectroscopy. The thermolysis was carried out at 700–1050 °C under an inert atmosphere. The resulting products were found to possess diverse electrical properties, revealed through very different impedance responses. As-synthesized MOF material was an insulator with a conductivity of σ = 1.3 × 10 –11 S cm –1 . Products obtained at 700–800 °C behaved as semiconductors with low room temperature conductivity of ca. σ ≈ 10 –6 –10 –5 S cm –1 and strong thermal dependence (σ ≈ 10 –3 S cm –1 at 200 °C). They exhibited complex impedance responses, which may be interpreted as mixed conduction, where semiconducting behavior was accompanied by ionic charge transfer. The final product obtained at 1050 °C exhibited a particular metal-like conductance with positive but weak temperature dependence and ambiance conductivity of σ = 9.0 × 10 –2 S cm –1 . The properties of Pt/carbon-based material obtained at 950 °C seem to be transient between the latter two conduction states. Thermolysis of initial MOF-253 is less hindered and occurs at lower temperatures. The conductivity of the final product of pyrolysis at 1050 °C of initial MOF-253 was inferior to that of Pt-MOF with σ 25 ° C = 1.0 × 10 –2 S cm –1 . A tentative interpretation of the results is presented.
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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 | 0.000 |
| 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) | 0.001 | 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".