Thema der Dissertation:
Probing Time-Dependent Dynamics in Electrocatalysts via In Situ and Operando X-ray Absorption Spectroscopy - Sub-second to long-term investigations of the dynamics of mono- and bimetallic Cu-based nanocatalysts for the electrocatalytic CO2 reduction
Probing Time-Dependent Dynamics in Electrocatalysts via In Situ and Operando X-ray Absorption Spectroscopy - Sub-second to long-term investigations of the dynamics of mono- and bimetallic Cu-based nanocatalysts for the electrocatalytic CO2 reduction
Abstract: This thesis explores the dynamic behavior of Cu-based electrocatalysts during the electrocatalytic reduction of CO2 employing in situ and operando X-ray absorption spectroscopy (XAS). XAS is an invaluable tool for probing the atomistic structure and bulk electronic properties of catalysts and allows to track time-resolved changes in the catalyst’s local structure in complex reaction environments. However, the analysis of synchrotron- and laboratory-based operando XAS data, remains challenging, especially when tracking unique heterogeneous structural motifs in multi-element systems or low amounts of minority species. Data analysis methods need to be advanced to disentangle these contributions under different conditions.
In this work, I have developed methodologies for advanced operando XAS data acquisition and analysis on the example of mono- and bimetallic Cu-based materials employed for the electrocatalytic conversion of CO2 to value-added products under industrially relevant conditions, including high current densities or pulsed potentials. By employing time-resolved operando XAS, combined with supervised and unsupervised machine learning methods, I studied the evolution of the catalyst’s chemical state and atomistic structures under these conditions. For bimetallic catalysts, I probed the influence of the secondary metal on the Cu redox properties. Finally, I developed a new setup and methodology combining electrocatalysis with laboratory-based XAS, allowing time-resolved tracking of the catalyst transformations and stability over several days.
To conclude, this thesis aims to advance the operando XAS methodology in the field of (electro-)catalysis and contributes to the progress in unraveling the dynamics of catalysts on all time scales, from catalyst restructuring processes occurring within seconds, to sluggish changes that require several hours or days to take place.
In this work, I have developed methodologies for advanced operando XAS data acquisition and analysis on the example of mono- and bimetallic Cu-based materials employed for the electrocatalytic conversion of CO2 to value-added products under industrially relevant conditions, including high current densities or pulsed potentials. By employing time-resolved operando XAS, combined with supervised and unsupervised machine learning methods, I studied the evolution of the catalyst’s chemical state and atomistic structures under these conditions. For bimetallic catalysts, I probed the influence of the secondary metal on the Cu redox properties. Finally, I developed a new setup and methodology combining electrocatalysis with laboratory-based XAS, allowing time-resolved tracking of the catalyst transformations and stability over several days.
To conclude, this thesis aims to advance the operando XAS methodology in the field of (electro-)catalysis and contributes to the progress in unraveling the dynamics of catalysts on all time scales, from catalyst restructuring processes occurring within seconds, to sluggish changes that require several hours or days to take place.
Zeit & Ort
12.02.2026 | 12:30
Seminarraum T1 (1.3.21)
(Fachbereich Physik, Arnimallee 14, 14195 Berlin)