Abdel-Mageed, A.; Klyushin, A.; Rezvani, A.; Knop-Gericke, A.; Schlögl, R.; Behm, R.: Negative Charging of Au Nanoparticles during Methanol Synthesis from CO2/H-2 on a Au/ZnO Catalyst: Insights from Operando IR and Near-Ambient-Pressure XPS and XAS Measurements. Angewandte Chemie - International Edition 58 (2019), p. 10325-10329
10.1002/anie.201900150
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Abstract:
The electronic and structural properties of Au/ZnO under industrial and idealized methanol synthesis conditions have been investigated. This was achieved by kinetic measurements in combination with time-resolved operando infrared (DRIFTS) as well as in situ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and X-ray absorption near-edge spectroscopy (XANES) measurements at the O K-edge together with high-resolution electron microscopy. The adsorption of CO during the reaction revealed the presence of negatively charged Au nanoparticles/Au sites during the initial phase of the reaction. Near-ambient-pressure XPS and XANES demonstrate the build-up of O vacancies during the reaction, which goes along with a substantial increase in the rate of methanol formation. The results are discussed in comparison with previous findings for Cu/ZnO and Au/ZnO catalysts.