Anomalous Increases in H<sub>2</sub>O<sub>2</sub> Production by Strained Ni(III) Centers during Electrocatalytic Oxygen Reduction on LaCr<sub>1–<i>x</i></sub>Ni<sub><i>x</i></sub>O<sub>3</sub>
Bibliographic record
Abstract
The electrochemical oxygen reduction reaction (ORR) plays a critical role in energy storage and conversion technologies and may provide a viable method for sustainable generation of H 2 O 2 for industrial use, but our understanding of the ways in which the catalyst structure alters reaction selectivity remains incomplete. Analysis of LaCr 1– x Ni x O 3 by X-ray diffraction and X-ray absorption spectroscopy reveals three stages of structural evolution across the composition series. The first stage is characterized by a blend of Ni(II) and Ni(III) residing within a distinct LaCrO 3 lattice, with an increasing proportion of Ni(III) as Ni content increases. Continued increases in Ni content induce substantial structural rearrangement that culminates in a phase transition from a Pnma lattice to R 3̅ c, all of which occur with negligible changes in the average Ni-oxidation state. Following the phase transition, the Ni(III) content continues to increase as the lattice compresses. Diverging reaction selectivity trends for Ni-rich and Cr-rich samples establish a narrow composition range of maximal H 2 O 2 selectivity, with highly strained Ni(III) sites present within a LaCrO 3 lattice found to be particularly selective for H 2 O 2 production during the ORR. We attribute the selectivity enhancements in Cr-rich samples to strain-induced alteration of the crystal field splitting for Ni(III) centers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".