Effect of alkali promotion on the catalytic performance of the synergetic K/Fe3O4-Fe5C2/Al2O3 catalyst for CO2 hydrogenation to light paraffins and olefines
Bibliographic record
Abstract
A series of K/α-Fe 2 O 3 /γ-Al 2 O 3 catalysts with high specific surface area (150–300 m 2 /g) and various levels of alkali promotion (0–11 wt% K) were synthesized using the reverse microemulsion method. The capacity of the catalysts to transform CO 2 into light olefins and paraffins via direct hydrogenation at moderate pressures was examined. The effect of potassium loading was investigated in the 300–500 °C range at 11 bar, evaluating catalytic performance in terms of CO 2 conversion, C2+ selectivity, and space time yield (STY). Reaction tests showed that 7.8 wt% K loading provides the highest CO 2 conversion and C2+ selectivity, of 45 % and 46 %, respectively, with a space time yield of 6.5 mmol g −1 h −1 at 11 bar and 400 °C. The catalyst without alkali promotion provided only 24 % CO 2 conversion, 12 % C2 + selectivity, and a space time yield of 0.87 mmol g −1 h −1 . Under reaction conditions α-Fe 2 O 3 was converted to a mixture of Fe 3 O 4 and χ-Fe 5 C 2 nanoparticles that act synergistically to reduce and hydrogenate CO 2 . Alkali promotion notably enhanced the formation of χ-Fe 5 C 2 , leading to higher selectivity to C2 + hydrocarbons.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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 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".