Understanding the Effect of Ni-Substitution on the Oxygen Evolution Reaction of (100) IrO<sub>2</sub> Surfaces
Bibliographic record
Abstract
The electrolysis process of water is impeded by the slow kinetics of the oxygen evolution reaction (OER). While iridium oxide (IrO2) is considered one of the most efficient metal catalysts for the OER, the adsorption of the OER intermediates at the IrO2 surface is not optimal, the *OH intermediate being too strongly adsorbed. The substitution of iridium by another metal cation is then a common strategy to improve the catalytic activity. A combined computational and experimental approach was followed to elucidate the fundamental effect of nickel on the OER activity of (100)-oriented IrO2. To achieve this, (100)-oriented Ir1–xNixO2 model surfaces were synthesized by pulsed laser deposition. Detailed structural and chemical characterizations were performed by X-ray diffraction, transmission electron microscopy, atomic force microscopy, and X-ray absorption spectroscopy. The composition of the film was varied between 0 and 15 at %, which is the solubility limit for the substitution of iridium by nickel atoms in (100)-oriented Ir1–xNixO2. All electrochemical characterizations were performed in an alkaline electrolyte, in which nickel dissolution is not observed by X-ray photoelectron spectroscopy. The current density recorded at +1.6 V (vs RHE) was increased from 35 to 348 μA cmox–2 between IrO2 to Ir0.85Ni0.15O2. Density functional theory calculations showed that the energy diagram of the OER intermediates was modified by the substitution of iridium with nickel atoms through a ligand effect. Also, it was found that iridium is the active site for low nickel content, whereas nickel is the most active site when its concentration reaches 15 at %.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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".