Structure Matters: Asymmetric CO Oxidation at Rh Steps with Different Atomic Packing
- Universidad del País Vasco, San Sebastián (Spain)
- Lund Univ. (Sweden)
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, San Sebastián (Spain)
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- NAPP Station, CIRCE Beamline, ALBA synchrotron, Cerdanyola del Vallès (Spain)
- Universidad del País Vasco, San Sebastián (Spain); Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, San Sebastián (Spain); Donostia International Physics Centre, San Sebastián (Spain)
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 CO2 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.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Basque Government; Ministry of Science, Innovation and Universities (MICINN); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 2319175
- Report Number(s):
- BNL--225367-2024-JAAM
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 33 Vol. 144; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Step Effects on the Dissociation of NO on Close-Packed Rhodium Surfaces
The structure and reactivity of adsorbates on stepped Rh and Pt surfaces investigated by LEED, HREELS, TPD, XPS and STM