Live Imaging of Silver Nanostructures Electrochemically Dissolving at Open‐Circuit Potential

TL;DR

This paper shows how silver nanostructures dissolve on platinum electrodes under open-circuit conditions, using advanced imaging and electrochemical methods.

Contribution

A new workflow combining live imaging and electrochemical testing reveals nanoscale dissolution mechanisms of electrocatalysts.

Findings

Silver electrodeposits dissolve on platinum under open-circuit potential due to oxygen reduction and bimetallic corrosion.

Nanoscale structural changes correlate with macroscopic electrochemical responses during dissolution.

The workflow provides a blueprint for studying catalyst degradation in energy systems.

Abstract

The stability of electrode and electrocatalyst materials is of paramount importance for sustainable and persistent technological solutions for energy conversion systems. In fact, dissolution of electrodes at open‐circuit potential occurs both during electrochemical testing operando and using a scanning flow cell‐inductively coupled plasma‐mass spectrometry (SFC‐ICP‐MS) setup. Although these phenomena occur frequently, their mechanisms remain concealed. This is because structural changes occur at the nanoscale, which are difficult to observe directly. Herein, we introduce a workflow comprising automated image analysis, beam effect assessment, and correlative electrochemical testing to obtain quantitative and representative data from electrochemical liquid phase electron microscopy (EC‐LP‐EM). In a demonstrator experiment, we reveal that the dissolution of silver electrodeposited on a platinum electrode substrate is driven by system equilibration involving the oxygen reduction reaction and bimetallic corrosion. This combination of reactions occurs at the electrode‐electrolyte interface under zero net current conditions as an example of structural changes on the nanoscale during operation. Our experimental findings, furthermore, serve as a blueprint for correlating nanoscale live imaging information with macroscopic electrochemical responses to investigate degradation mechanisms of electrocatalysts and materials beyond. These insights aid in designing efficient electrochemical conversion systems, urgently needed in renewable energy technology.

Stability of electrocatalysts as used in energy conversion systems is pivotal for sustainable technologies, yet degradation dynamics at the nanoscale remain elusive. Harnessing beam‐effect corrected electrochemical liquid phase electron microscopy combined with correlative bulk‐scale electrochemical testing reveals silver corrosion on platinum under open‐circuit conditions driven by oxygen reduction reaction. This article is, therefore, a blueprint for advanced catalyst degradation analysis.

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