| Abstract Scope |
One of the grand challenges of energy materials is identifying the active sites and capturing real-time “movies” of catalytic processes, i.e., watching catalysis in action.1 It is increasingly evident that pristine and post-mortem electrocatalysts, characterized ex situ, most likely do not maintain the same active structures under electrochemical conditions. The need to establish structure-(re)activity correlations in electrocatalysis motivates the development of operando (operating) methods.
I will present our recent progress in probing dynamic structural evolution of energy materials by developing multimodal operando electrochemical liquid-cell scanning transmission electron microscopy (EC-STEM) and synchrotron-based high-energy-resolution X-ray spectroscopy to across multiple spatiotemporal scales.[1-3] Operando electrochemical 4D-STEM in liquid, assisted by machine learning, has shown great potential to interrogate complex structures of active sites of energy materials at solid-liquid interfaces. My group recently employed operando electrochemical 4D-STEM to provide the first direct nanoscale movies visualizing evolution from single-atom catalysts to active Cu nanostructures for CO2 reduction to liquid fuels.[4] I will then introduce our instrument development on the first-of-its-kind operando heating and cooling EC-STEM to diagnose battery failure mechanisms below freezing temperatures and catalyst degradation mechanisms at elevated temperatures.[5] I will conclude my talk with preliminary results on atomic-scale in situ STEM imaging and 4D-STEM diffraction mapping in liquids [6].
1.Yang, Nature 2023, 614, 262
2.Yang, Nature Catalysis 2025, 8, 579
3. Yang*, J. Am. Chem. Soc. 2024, 146, 23398
4. Choi, Yang*, J. Am. Chem. Soc. 2025, 147, 37808
5. Kim, Yang*. J. Am. Chem. Soc. 2025, 147, 23654
6. Unpublished |