Catalytic synthesis of carbon nanotubes from the decomposition of methane over a Ni–Co/La<sub>2</sub>O<sub>3</sub> catalyst
Bibliographic record
Abstract
The production of multi-walled carbon nanotubes (MWNTs) by the catalytic chemical vapour deposition (CCVD) method was examined over a series of Ni–Co/La2O3 catalysts with methane as the carbon source. The catalyst composition and the reaction conditions were optimized by analyzing the effluent gas with gas chromatography. Various techniques, such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), Raman spectra, and Thermal gravimetric analysis (TGA) were used to characterize the catalysts and products. The results indicate that the unreduced catalyst 30Ni–10Co/La2O3 showed the highest activity for methane decomposition, and the highest carbon yield, being 624.2%, was obtained over this catalyst at 700 °C after 60 min of reaction with hydrogen as carrier gas. TGA results suggest that the purity of carbon nanotubes (CNTs) can reach up to 98 wt% after a single-step purification by hydrochloric acid.Key words: carbon nanotubes, catalytic chemical vapour deposition, methane decomposition, Ni–Co/La2O3 catalyst.
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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) | 0.000 | 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".