An exploratory kinetic analysis of photoelectrochemical oxygen evolution on hematite
Bibliographic record
Abstract
Abstract The kinetics of the photoelectrochemical oxygen evolution reaction (POER) on hematite photoanodes are explored using a simple reaction scheme involving an initial pre-equilibrium hole/proton transfer step to form an Fe(IV) surface species, Fe = O, followed by a rate-determining hole/proton transfer step to form the Fe(II) peroxo species, FeOOH, which then reacts rapidly with two more holes to form oxygen. The modelling considers how the kinetics of these two reaction steps are affected by changes in $${V}_{\text{H}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>V</mml:mi> <mml:mtext>H</mml:mtext> </mml:msub> </mml:math> , the potential drop across the Helmholtz layer that arises from the build-up of positive charge at the interface under illumination. The model, which also considers electron–hole recombination and back reaction of Fe = O with conduction band electrons, is used to calculate steady-state photocurrent/voltage characteristics, pseudocapacitance-voltage plots, and transient absorbance (TAS) responses that can be compared with published results. The model is also used to show that the slopes of double logarithmic reaction order plots of photocurrent vs. hole or reaction intermediate concentrations are influenced by light-induced changes in $${V}_{\text{H}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>V</mml:mi> <mml:mtext>H</mml:mtext> </mml:msub> </mml:math> . The insights from this analysis should be relevant to the ongoing discussion of multi-hole mechanisms for the POER on 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 | 0.000 | 0.000 |
| 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".