Operando Vitrifying of Electrocatalysts Under Applied Potential for Analysis of Active Electrolyte/Catalyst Interfaces Using CryoEM

Electrocatalysts are critical for applications in fuel and product synthesis using renewable electricity; however, in-situ analysis of catalyst surfaces with high spatial resolution remains a significant challenge and current techniques have substantial limitations. In this study, we employ operando vitrifying techniques developed for Cryogenic Transmission Electron Microscopy (CryoEM) to preserve the morphology of electrocatalysts under applied potential. We conducted electrochemical characterization of catalyst samples in a three-electrode setup, alongside CryoEM imaging, to analyze degradation at various stages of operation. The optimization of sample cells, including the selection of counter electrode materials and films to retain electrolyte, was performed using electrochemical impedance spectroscopy and cyclic voltammetry. The tweezer configuration for plunge-freezing was modified to withstand the application of high overpotentials while preventing oxidation of the tweezer components. Electrocatalyst samples were frozen under operating conditions and imaged at cryogenic temperatures. Initial CryoEM results and analysis will be discussed, providing insights into electrochemical degradation mechanisms.

Acknowledgements:
CryoEM for Electrochemical Energy Materials FWP #100886.
Part of this work was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-2026822.
Some of this work was performed at the Stanford-SLAC Cryo-EM Center (S²C²), which is supported by the National Institutes of Health Common Fund Transformative High-Resolution Cryo-Electron Microscopy program (U24 GM129541). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.