Correlating Raman and X-Ray Absorption Spectroscopy to Analyze Defects in Hematite Photoandoes
Bibliographic record
Abstract
Over two decades of research on hematite photoanodes have generated significant information on the electronic structure, photophysics and electron transfer mechanism for the oxygen evolution reaction. A surprisingly high degree of variability in photoelectrocatalytic performance continues across the literature despite these advances, however, suggesting missing information and uncontrolled variables. This encouraged us to pursue spectroscopic methods capable of identification, and possibly quantification of specific defects within the hematite lattice, and to map their presence to behaviors observed in photoelectrochemistry. We approach this issue by applying structure-property analysis to hematite samples treated under either O 2 or N 2 environments with variable performance in photoelectrocatalytic oxygen evolution. X-ray absorption fine-structure spectroscopy and Raman spectroscopy can provide short-range coordination shells and longer-range order feature respectively to describe the structure of samples across the series. Different correlations between these structural parameters and photoelectrochemical performance reveal distinct defects for sample sets annealed in O 2 or N 2 . These distortions can be observed by processed Raman spectrum data, suggesting that it may be possible to calibrate the width, energy, and intensity of peaks in Raman spectra to enable direct analysis of defects in hematite photoanodes.
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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 | 0.000 |
| 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".