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

Fernando García-Martínez, Lisa Rämisch, Khadiza Ali, Iradwikanari Waluyo, Rodrigo Castrillo Bodero, Sebastian Pfaff, Ignacio J. Villar-García, Andrew Leigh Walter, Adrian Hunt, Virginia Pérez-Dieste, Johan Zetterberg, Edvin Lundgren, Frederik Schiller, J. Enrique Ortega

Research output: Contribution to journalArticlepeer-review


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 CO2fluorescence 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.

Original languageEnglish
Pages (from-to)15363-15371
Number of pages9
JournalJournal of the American Chemical Society
Issue number33
Publication statusPublished - 2022 Aug 24

Subject classification (UKÄ)

  • Inorganic Chemistry


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