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Structure Matters: Asymmetric CO Oxidation at Rh Steps with Different Atomic Packing

[Image: see text] Curved crystals are a simple but powerful approach to bridge the gap between single crystal surfaces and nanoparticle catalysts, by allowing a rational assessment of the role of active step sites in gas-surface reactions. Using a curved Rh(111) crystal, here, we investigate the eff...

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Detalles Bibliográficos
Autores principales: García-Martínez, Fernando, Rämisch, Lisa, Ali, Khadiza, Waluyo, Iradwikanari, Bodero, Rodrigo Castrillo, Pfaff, Sebastian, Villar-García, Ignacio J., Walter, Andrew Leigh, Hunt, Adrian, Pérez-Dieste, Virginia, Zetterberg, Johan, Lundgren, Edvin, Schiller, Frederik, Ortega, J. Enrique
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9413197/
https://www.ncbi.nlm.nih.gov/pubmed/35960901
http://dx.doi.org/10.1021/jacs.2c06733
Descripción
Sumario:[Image: see text] Curved crystals are a simple but powerful approach to bridge the gap between single crystal surfaces and nanoparticle catalysts, by allowing a rational assessment of the role of active step sites in gas-surface reactions. Using a curved Rh(111) crystal, here, we investigate the effect of A-type (square geometry) and B-type (triangular geometry) atomic packing of steps on the catalytic CO oxidation on Rh at millibar pressures. Imaging the crystal during reaction ignition with laser-induced CO(2) fluorescence demonstrates a two-step process, where B-steps ignite at lower temperature than A-steps. Such fundamental dissimilarity is explained in ambient pressure X-ray photoemission (AP-XPS) experiments, which reveal partial CO desorption and oxygen buildup only at B-steps. AP-XPS also proves that A-B step asymmetries extend to the active stage: at A-steps, low-active O–Rh–O trilayers buildup immediately after ignition, while highly active chemisorbed O is the dominant species on B-type steps. We conclude that B-steps are more efficient than A-steps for the CO oxidation.