Distinguishing Surface versus Buried Cation Sites in Aluminosilicate Mesoporous Materials
Bibliographic record
Abstract
Mesoporous MCM-41 aluminosilicates were prepared through direct synthesis and surface grafting resulting in the incorporation of aluminum into the pore walls and onto the wall surface, respectively. 7Li and 23Na NMR studies of ion-exchanged Li and Na-Al-MCM-41 were able to distinguish between cations in the surface region and those buried deeper in the pore walls. Thus it was demonstrated that most of the cations in the grafted Al-MCM-41 locate in the surface region, whereas the cations in the synthesized Al-MCM-41 are distributed throughout the pore walls. The NMR spectra of dehydrated Li- and Na-MCM-41 resemble those of glassy materials, reflecting the amorphous nature of this class of mesoporous materials. 7Li NMR studies of dehydrated Li-Al-MCM-41 prepared from direct synthesis in the presence of oxygen showed that most of the Li+ cations are not accessible to O2, while the Li+ cations in Al-grafted Li-Al-MCM-41 are accessible, which also confirms their locations. This study provides valuable insights for the understanding of the structure and properties of aluminosilicate mesoporous materials.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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".