Unraveling the Redox Behavior of a CoMoS Hydrodesulfurization Catalyst: A Scanning Transmission X-ray Microscopy Study in the Tender X-ray Range
Bibliographic record
Abstract
We visualize the elemental zoning in an alumina-supported cobalt molybdenum sulfide (CoMoS) catalyst with scanning transmission X-ray microscopy (STXM). We use the Canadian Light Source beamline 10-ID’s (SM) unique combination of soft X-ray and tender X-ray STXM to determine the spatial variation of Co, Al, Mo, and S species. The results clearly show the correlation between cobalt and molybdenum and the anticorrelation between cobalt and alumina, confirming that Co is closely associated with the MoS 2 phase. The tender X-ray STXM images show that the fresh catalyst particle contains a 50 nm ring of molybdenum oxide encapsulating the supported MoS 2 phase. After the reduction at 200 °C with H 2, this oxide rim disappears and a uniform MoS 2 distribution is found. Upon oxidation at 400 °C, the sulfur disappears from the catalyst sample and molybdenum is oxidized from a Mo IV sulfide to a mainly tetrahedral Mo VI oxide, while cobalt keeps its divalent nature and changes from a Co II sulfide to a Co II oxide.
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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".