Description
Photo- and electrocatalytically active materials are expected to play an essential role in the transition towards sustainable processes for energy storage and chemical conversion. Performance and stability of the materials still need to be improved. Yet, the microscopic origin of their current limitations is poorly understood. One key limitation is the lack of suitable techniques that allow for a detailed characterization of the structural and electrical properties of the interfaces on the nanometer scale. In this lecture, I describe our recent progress in establishing in situ and operando AFM spectroscopy for characterizing the surface charge and its response to illumination on photocatalytically active faceted nanoparticles of SrTiO3 and BiVO4 in ambient electrolytes of variable composition. Our measurements demonstrate the existence and pH-dependence of differences in the surface potential between adjacent crystal facets, which are believed to drive the separation of photo-generated electron-hole pairs in photocatalysis. For visible light-driven BiVO4, we monitor the variations of the local surface charge upon illumination, from which we extract the local surface photovoltage and thus the accumulation of charge carriers at the interfaces. The measurements suggest a strong influence of surface defects such as steps and disordered regions between adjacent facets for the accumulation of photo-excited charge carriers.I will conclude the lecture with an outlook on upcoming challenges in AFM-based characterization of electrocatalytic materials for the energy transition and their transformations under operando conditions.
| Period | 28 Mar 2025 |
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| Event title | Charged Matter 2025 |
| Event type | Conference |
| Organiser | Institute of Science and Technology Austria |
| Location | Klosterneuburg, AustriaShow on map |
| Degree of Recognition | International |