Selective Participation of Methane in Olefin Upgrading over Pd/ZSM‐5 and Ir/ZSM‐5: Investigation using Deuterium Enriched Methane
Bibliographic record
Abstract
Abstract The upgrading of olefins under methane environment is a promising process. Not only is the olefin content reduced, which is critical for the storage and transportation of oil products, but also are high value‐added products produced from methane. The study on the reaction intermediates during this process is crucial for a better understanding of the involved catalytic reaction mechanism as well as catalyst development. Catalysts that displayed high selectivity towards olefin upgrading including Ir/ZSM‐5 and Pd/ZSM‐5 in our previous research are studied in this work. CD4 is employed as the methane source in the reaction to track the evolution of hydrogen in the methane molecule. The significant change of the allylic hydrogen peak on 1H NMR spectra upon CD4 introduction demonstrates that the hydrogen sites on the carbon atoms adjacent to the double bond moieties are selectively occupied by deuterium atoms, suggesting that these sites are preferred by methane hydrogen atoms and may play a key role in the reaction pathway. The evolution of methane and the interaction between methane and olefin over the catalyst are observed in the DRIFT spectra. The IR resonance due to O−D stretching of the terminal silanol hydroxyl group at 2753 cm−1 is observed under CD4 environment, while the O−D stretching of bridging hydroxyl group is not detected, indicating the interaction between methane and the catalyst is highly selective, which may contribute to the high selectivity in methane hydrogen evolution.
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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".