Real Time Determination of the Electronic Structure of Unstable Reaction Intermediates during Au2O3 Reduction.
Chemical reactions are always associated with electronic structure changes of the involved chemical species. Determining the electronic configuration of an atom allows probing its chemical state and gives understanding of the reaction pathways. However, often the reactions are too complex and too fast to be measured at in situ conditions due to slow and/or insensitive experimental techniques. A short-lived Au2O compound has been detected for the first time under in situ conditions during the temperature-programmed reduction of Au2O3. A time-resolved resonant inelastic X-ray scattering experiment (RIXS) allowed the determination of changes in the Au electronic structure, enabling a better understanding of the reaction mechanism of Au(III) reduction. On the basis of time-resolved RIXS data analysis combined with genetic algorithm methodology, we determined the electronic structure of the metastable Au2O intermediate species. The data analysis showed a notably larger value for the lattice constant of the intermediate Au as compared to the theoretical predictions. With support of DFT calculations, we found that such a structure may indeed be formed and that the expanded lattice constant is due to the termination of Au2O on the Au2O3 structure.
†Paul Scherrer Institut, Villigen, Switzerland.|‡Institute of Physics, Jan Kochanowski University, Kielce, Poland.
Jakub
J
Szlachetko
†Paul Scherrer Institut, Villigen, Switzerland.|§LSU Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Jacinto
J
Sá
†Paul Scherrer Institut, Villigen, Switzerland.
Maarten
M
Nachtegaal
†Paul Scherrer Institut, Villigen, Switzerland.|⊥Department for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland.
Urs
U
Hartfelder
#Department of Physics, University of Fribourg, Fribourg, Switzerland.
Jean-Claude
JC
Dousse
#Department of Physics, University of Fribourg, Fribourg, Switzerland.
Joanna
J
Hoszowska
∥Department of Chemistry, University of Aveiro, Aveiro, Portugal.
Daniel Luis
DL
Abreu Fernandes
¶School of Physics, The University of Sydney, Sydney, Australia.
Hongqing
H
Shi
¶School of Physics, The University of Sydney, Sydney, Australia.
Catherine
C
Stampfl
DFT calculations; X-ray spectroscopy; short-lived Au2O intermediate; time-resolved RIXS