In Situ X-Ray Photoelectron Spectroscopy of Model Catalysts: At the Edge of the Gap

S. Blomberg, M. J. Hoffmann, J. Gustafson, N. M. Martin, V. R. Fernandes, A. Borg, Z. Liu, R. Chang, S. Matera, K. Reuter, and E. Lundgren

Phys. Rev. Lett. 110, 117601 – Published 12 March 2013

Abstract

We present high-pressure x-ray photoelectron spectroscopy (HP-XPS) and first-principles kinetic Monte Carlo study addressing the nature of the active surface in CO oxidation over Pd(100). Simultaneously measuring the chemical composition at the surface and in the near-surface gas phase, we reveal both O-covered pristine Pd(100) and a surface oxide as stable, highly active phases in the near-ambient regime accessible to HP-XPS. Surprisingly, no adsorbed CO can be detected during high ${CO}_{2}$ production rates, which can be explained by a combination of a remarkably short residence time of the CO molecule on the surface and mass-transfer limitations in the present setup.

Received 29 August 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.117601

Authors & Affiliations

S. Blomberg^1,*, M. J. Hoffmann², J. Gustafson¹, N. M. Martin¹, V. R. Fernandes³, A. Borg³, Z. Liu⁴, R. Chang⁴, S. Matera², K. Reuter², and E. Lundgren¹

¹Division of Synchrotron Radiation Research, Lund University, Box 118, SE-221 00 Lund, Sweden
²Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
³Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
⁴ALS, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA