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 L. Walter, Adrian Hunt, Virginia Pérez‐Dieste, Johan Zetterberg, Edvin Lundgren, Frederik Schiller, J. Enrique Ortega
Abstract
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.