Aqueous Interfacial Chemistry in the Catalyst Preparation of NiMo/Al<sub>2</sub>O<sub>3</sub> System by EDTA-Containing Impregnation
Bibliographic record
Abstract
The present work studies the effect of organic chelating agents on the solution−support interfacial process during the catalyst preparation. EDTA−Ni(II)−Mo(VI)−γ-Al 2 O 3 −H 2 O is used as a representative catalyst synthesis system. It has been found that Ni(II) adsorption increases with pH value starting from pH 6 and reaches a maximum at pH 8 without EDTA, whereas the adsorption vs pH is reversed (maximum at pH 3.5 and no adsorption at pH 9) when EDTA is introduced into this system with a molar ratio of EDTA/Ni(II) = 1. According to ion-exchange theory, Ni(II) possibly forms a surface ternary complex with the alumina surface sites through EDTA acting as a bridge. It has also been found that Mo(VI) adsorption decreases with pH (maximum at pH 3 and no adsorption at pH 9) in the absence of EDTA. EDTA suppresses the adsorption of Mo(VI), although the adsorption of Mo(VI) vs pH remains the same. EDTA has a higher coordinating constant with the surface Al 3+ than do Mo(VI) anions. Free EDTA competes with Mo(VI) on the alumina surface sites. Because EDTA has a preference to chemically bond with Ni(II), which forms a stable complex, Ni−EDTA could be selectively adsorbed on the alumina surface. On the basis of these experimental results, it can be rationalized that EDTA promotes the dispersion of both Ni(II) and Mo(VI) on alumina. Meanwhile, EDTA also limits strong interactions between the metal ions and alumina, thereby contributing to the formation of more vigorous sites.
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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 | 0.000 |
| 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 | 0.001 |
| Open science | 0.001 | 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".