Postmortem analysis with tomography holder supplements in-situ liquid cell TEM

How does electrochemical reduction affect the structure and chemistry of catalysts?

Philipp Grosse, Aram Yoon, See Wee Chee and Beatriz Roldan Cuenya, and their colleagues at the Fritz-Haber Institute of the Max Planck Society combined ex-situ benchtop electrochemistry with in-situ electrochemical transmission electron microscopy (EC-TEM) and ex-situ STEM-EDS using their Hummingbird Scientific in-situ TEM liquid cell sample holder, and Hummingbird Scientific single-tilt tomography holder. Both TEM holders are part of a comprehensive suite of Hummingbird TEM holders aimed at characterization of electrochemical processes.

Figures showing morphology of Cu2O cubes and their evolution during CO2 reduction reaction. a) Morphological changes observed in ~170 nm cubes after (i) introducing CO2 saturated 0.1M KHCO3 under open circuit potential, (ii) while applying a reductive potential of −1.1 VRHE and (iii) after ~9 min at −1.1 VRHE. Comparison of Cu2O cubes b) before and c) after reaction using ex situ TEM. d) STEM-EDX maps showing the Cu and O signals. Copyright © 2021 Springer Nature Limited

In-situ EC-TEM experiments performed using the Hummingbird Scientific liquid electrochemistry holder enabled real-time visualization of Cl^–-stabilized Cu₂O nanocube catalyst fragmentation and nanoparticle redeposition under CO₂ reduction reaction (CO₂RR) conditions. Ex-situ TEM imaging and STEM-EDS analysis performed after reaction completion using the ultra stable tomography holder supplemented the particle dynamics revealed by the in-situ work. While the liquid holder has suitable clearance for EDS signal collection, inherent limitations of imaging resolution and spectroscopy in any liquid cell favored a more highly detailed postmortem characterization. EDS maps in the tomography holder reveal chemical evolution that is often obscured –via both the x-ray signal and e-beam resolution– by the solution. In this case decreases in both O and Cl signatures after reaction are observed. Overall, this work exemplifies the unique insights into nanomaterial synthesis and catalysis that can be gained with an integrated electron microscopy workflow.

Reference: Philipp Grosse, Aram Yoon, Clara Rettenmaier, Antonia Herzog, See Wee Chee, and Beatriz Roldan Cuenya, Nature Communications 12 6736 (2021) DOI: 10.1038/s41467-021-26743-5

View All News