Publication: Using Auger transitions as a route to determine the oxidation state of copper in high-pressure electron spectroscopy
Program
KU-Authors
KU Authors
Co-Authors
Soldemo, Markus
Garcia-Martinez, Fernando
Goodwin, Christopher M.
Loemker, Patrick
Shipilin, Mikhail
Nilsson, Anders
Amann, Peter
Weissenrieder, Jonas
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Embargo Status
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Abstract
Accurate discrimination between metallic copper (Cu0) and cuprous oxide (Cu2O, Cu+) in electron spectroscopy commonly relies on the Auger electron spectroscopy (AES) Cu L3M4,5M4,5 transitions, as the X-ray photoelectron spectroscopy (XPS) Cu core-levels do not provide large enough binding energy shifts. The kinetic energy of the AES Cu L3M4,5M4,5 electrons is 917 eV, which leaves the AES electron susceptible for efficient scattering in the gas phase and attenuation of the signal above near-ambient pressure conditions. To study copper-based materials at higher pressures, e.g., the active state of a catalyst, Auger transitions providing electrons with higher kinetic energies are needed. This study focuses on AES transitions involving the Cu K-shell (1s electrons) that exhibit discernible kinetic energy shifts between the oxidation states of Cu. It is shown that the AES Cu KL2M4,5 transition, with kinetic energy of 7936 eV, provides a large enough kinetic energy shift between metallic copper and Cu2O. AES signal is demonstrated in an ambient of 150 mbar CO2.
Source
Publisher
Elsevier
Subject
Chemistry, physical, Physics, condensed matter
Citation
Has Part
Source
Surface Science
Book Series Title
Edition
DOI
10.1016/j.susc.2024.122565