Nano-sized carbon-supported molybdenum disulphide particles for hydrodesulphurization
Bibliographic record
Abstract
Canadian bitumen is a plentiful source of hydrocarbons. However, to obtain oils which may be sold to consumers, bitumen must be upgraded. Among other processes, bitumen upgrading includes lowering sulphur content and correcting the carbon to hydrogen ratio mostly by carbon rejection, which results in the formation of petroleum coke (PC), a byproduct which must be stored or disposed of. This study's focus was the preparation of a molybdenum disulphide (MoS₂) catalyst for a more facile removal of intercalated sulphur from bitumen, by synthesising nano-sized MoS₂ particles. Simultaneously, this study attempted to use PC as a catalyst support. Carbon-supported MoS₂ catalysts were successfully prepared by two methods using ammonium tetrathiomolybdate: reverse micelles using the water/IGEPAL CO-520/cyclohexane system, and incipient wetness impregnation from ultra pure water. MoS₂ prepared by impregnation was supported on PC, and MoS₂ prepared by reverse micelles was supported on both PC and activated carbon (AC). Catalysts prepared by reverse micelles contained nanosized MoS₂ with low stacking order, and the catalyst prepared by impregnation consisted of long sheets of MoS₂ with a higher stacking order. The catalysts were screened for hydrodesulphurization activity in a novel slurry-phase batch microreactor using dibenzothiophene as a model compound. The overall rate constant for DBT conversion per gram of molybdenum for the MoS₂/PC prepared by impregnation was greater than that for the catalysts prepared by reverse micelles in the temperature range of 350 - 375 °C. MoS₂ supported on AC and PC showed a similar activity toward catalysing the HDS of DBT when the MoS₂ was prepared by reverse micelles; therefore, PC is a good alternative support to AC for MoS₂/C catalysts prepared by this method. The rate constant associated with hydrogenation was an order of magnitude greater for the catalyst prepared by impregnation than that for the catalysts prepared by reverse micelles. It was concluded that the larger stacking order in MoS₂/PC prepared by impregnation provided more sites for hydrogenation, which resulted in an overall larger rate constant than that for the catalysts prepared by reverse micelles, whose MoS₂ stacking orders were minimal due to the small particle size.
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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 | 0.000 | 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 | 0.001 | 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 teacher head, 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".