Structure Matters: Asymmetric CO Oxidation at Rh Steps with Different Atomic Packing
Journal article, 2022
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.
Author
Fernando Garcia-Martinez
Deutsches Elektronen-Synchrotron (DESY)
University of the Basque Country (UPV/EHU)
Lisa Raemisch
Lund University
Khadiza Ali
University of the Basque Country (UPV/EHU)
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Iradwikanari Waluyo
Brookhaven National Laboratory
Rodrigo Castrillo Bodero
University of the Basque Country (UPV/EHU)
Sebastian Pfaff
Lund University
Ignacio J. Villar-Garcia
ALBA Synchrotron Light Facility
Adrian Hunt
Brookhaven National Laboratory
Virginia Perez-Dieste
ALBA Synchrotron Light Facility
Edvin Lundgren
Lund University
Frederik Schiller
University of the Basque Country (UPV/EHU)
J. Enrique Ortega
University of the Basque Country (UPV/EHU)
Donostia International Physics Center
Journal of the American Chemical Society
0002-7863 (ISSN) 1520-5126 (eISSN)
Vol. 144 33 15363-15371Subject Categories
Inorganic Chemistry
Other Chemical Engineering
Organic Chemistry
DOI
10.1021/jacs.2c06733
PubMed
35960901