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Insights into Electrocatalyst Transformations Studied in Real Time with Electrochemical Liquid-Phase Transmission Electron Microscopy.

Insights into Electrocatalyst Transformations Studied in Real Time with Electrochemical Liquid-Phase Transmission Electron Microscopy.

Authors :
Shen TH
Girod R
Tileli V
Source :
Accounts of chemical research [Acc Chem Res] 2023 Nov 07; Vol. 56 (21), pp. 3023-3032. Date of Electronic Publication: 2023 Oct 24.
Publication Year :
2023

Abstract

ConspectusThe value of operando and in situ characterization methodologies for understanding electrochemical systems under operation can be inferred from the upsurge of studies that have reported mechanistic insights into electrocatalytic processes based on such measurements. Despite the widespread availability of performing dynamic experiments nowadays, these techniques are in their infancy because the complexity of the experimental design and the collection and analysis of data remain challenging, effectively necessitating future developments. It is also due to their extensive use that a dedicated modus operandi for acquiring dynamic electrocatalytic information is imperative. In this Account, we focus on the work of our laboratory on electrochemical liquid-phase transmission electron microscopy (ec-LPTEM) to understand the transformation/activation of state-of-the-art nanocatalysts for the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and CO <subscript>2</subscript> electroreduction (CO <subscript>2</subscript> ER). We begin by describing the development of electrochemical microcells for TEM studies, highlighting the importance of tailoring the system to each electrochemical process to obtain reliable results. Starting with the anodic OER for alkaline electrolyzers, we demonstrate the capability of real-time monitoring of the electrowetting behavior of Co-based oxide catalysts and detail the fascinating insights gained into solid-liquid interfaces for the reversible surface reconstruction of the catalystic surfaces and their degradation processes. Importantly, in the case of the OER, we report the exceptional capacity of ec-LPTEM to probe gaseous products and therefore resolve solid-liquid-gas phenomena. Moving toward the cathodic ORR for fuel cells, we summarize studies that pertain to the evaluation of the degradation mechanisms of Pt nanoparticles and discuss the issues with performing real-time measurements on realistic catalyst layers that are composed of the carbon support, ionomer network, and Pt nanocatalysts. For the most cathodic CO <subscript>2</subscript> ER, we first discuss the challenges of spatiotemporal data collection in microcells under these negative potentials. We then show that control over the electrochemical stimuli is critical for determining the mechanism of restructuring/dissolution of Cu nanospheres, either for focusing on the first stages of the reaction or for start/stop operation studies. Finally, we close this Account with the possible evolution in the way we visualize electrochemical processes with ec-LPTEM and emphasize the need for studies that bridge the scales with the ultimate goal of fully evaluating the impact of the insights obtained from the in situ-monitored processes on the operability of electrocatalytic devices.

Details

Language :
English
ISSN :
1520-4898
Volume :
56
Issue :
21
Database :
MEDLINE
Journal :
Accounts of chemical research
Publication Type :
Academic Journal
Accession number :
37874852
Full Text :
https://doi.org/10.1021/acs.accounts.3c00463