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 15363-15371

Subject Categories

Inorganic Chemistry

Other Chemical Engineering

Organic Chemistry

DOI

10.1021/jacs.2c06733

PubMed

35960901

More information

Latest update

8/29/2022