Direct Nonoxidative Methane Coupling to Ethylene over Gallium Nitride: A Catalyst Regeneration Study
Bibliographic record
Abstract
The abundance of methane in natural and shale gases creates the need to develop processes for the direct conversion of methane to olefins, aromatics, and hydrogen. In this work, the regeneration capability and reusability of gallium nitride (GaN) catalysts for the direct nonoxidative methane activation with subsequent coupling to ethylene were studied. Unsupported GaN and silica-supported GaN/SBA15 catalysts were synthesized and evaluated. Each catalyst was subjected to two different regeneration methods. In the first method, the used catalysts were regenerated with air at 500–550 °C and reused several times. Due to the slight oxidation of the surface GaN to Ga 2 O 3, the ethylene yield decreased by 16% after five cycles. The second method included an intermediate renitridation step after air regeneration to convert the surface Ga 2 O 3 back to GaN. By doing so, the ethylene yield remained constant over multiple cycles.
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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".