The Structure of the Active Pd State During Catalytic Carbon Monoxide Oxidization

Publication

Author: Christopher M Goodwin, Mikhail Shipilin, Stefano Albertin, Uta Hejral, Patrick Lömker, Hsin-Yi Wang, Sara Blomberg, David Degerman, Christoph Schlueter, Anders Nilsson, Edvin Lundgren, Peter Amann The Journal of Physical Chemistry Letters
URL: https://doi.org/10.1021/acs.jpclett.1c00620
Date: 2021
Instruments: BAR XPS, HiPP-2

Using grazing incidence X-rays and X-ray photoelectron spectroscopy during the mass transfer limited catalytic oxidation of CO, the long-range surface structure of Pd(100) was investigated. Under the reaction conditions of 50:4 O2 to CO, 300 mbar pressure, and temperatures between 200 and 450 °C, the surface structure resulting from oxidation and the subsequent oxide reduction was elucidated. The reduction cycle was halted, and while under reaction conditions, angle-dependent X-ray photoelectron spectroscopy close to the critical angle of Pd and modeling of the data was performed. Two proposed models for the system were compared. The suggestion with the metallic islands formed on top of the oxide island was shown to be consistent with the data.