Effect of the Structural and Electronic Properties of Rh/CeXZr1-XO2 Catalysts on the Low-temperature Ethanol Steam-reforming
Bibliographic record
Abstract
Abstract. Rh catalysts supported on CexZr1–xO2 (with x= 0-1) materials were synthesized by precipitation method. The influence of the two different cerium salt precursors, ammonium cerium(IV) nitrate and cerium(III) nitrate hexahydrate, over the structure and catalytic activity in steam reforming reaction was investigated. The synthesized catalysts were characterized by various techniques, such as N2 adsorption-desorption, temperature-programmed desorption, X-ray diffraction, Raman spectroscopy, diffuse reflectance UV-Vis, and X-ray photoelectron spectroscopy. The use of ammonium cerium (IV) nitrate as a cerium precursor resulted in solid CexZr1-xO2 solutions with improved oxygen mobility and specific surface area. The catalytic evaluation exhibited the support composition and structure impact on its activity and product yield. The Rh supported on Ce0.5Zr0.5O2 solid solution rendered the higher activity and H2 and CO2 yields among both series, related to improved oxygen mobility and greater Rh0 dispersion. The formation of surface defects adjacent to Rh clusters by strong metal-support interaction effect was suggested by Raman analysis. The close contact between the Rh0 site and oxygen vacancy could be favoring cyclic-like ethanol adsorption and favored the breaking of the C–C bond and further oxidation of adsorbed CO and CHX species. Resumen. Los catalizadores de Rh soportados en materiales CexZr1 – xO2 (x= 0-1) se sintetizaron mediante el método de precipitación. En este trabajo se investiga la influencia de dos precursores de sal de cerio diferentes, nitrato de amonio cerio (IV) y nitrato de cerio (III) hexahidrato, sobre la estructura y la actividad catalítica en la reacción de reformado con vapor. Los catalizadores sintetizados se caracterizaron mediante diversas técnicas, tal como fisisorción de N2, reducción a temperatura programada, difracción de rayos X, espectroscopía Raman, reflectancia difusa UV-Vis y espectroscopía de fotoelectrones de rayos X. El uso de nitrato de amonio cerio (IV) como precursor de cerio dio como resultado la obtención de soluciones sólidas de CexZr1-xO2 con una movilidad del oxígeno y área específica mejorada. La evaluación catalítica mostró el impacto de la composición y estructura del soporte sobre la conversión y rendimiento de productos. El catalizador Rh soportado en la solución sólida Ce0.5Zr0.5O2 proporcionó la mayor actividad y rendimientos de H2 y CO2 entre ambas series, relacionados con la movilidad del oxígeno mejorada y mayor dispersión de Rh0. El análisis Raman sugirió la formación de defectos superficiales adyacentes a los grupos de Rh debido a fuertes interacciones metal-soporte. El contacto estrecho entre el sitio Rh0 y la vacante de oxígeno estaría favoreciendo la adsorción del etanol en configuración cíclica y favoreciendo la ruptura del enlace C-C y la oxidación de las especies de CO y CHX adsorbidas.
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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) | 0.000 | 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".