Nanoimpacts at Active and Partially Active Electrodes: Insights and Limitations

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Catalysis

Background:

• The electrochemical nanoimpact technique traditionally requires a catalytically active particle and an inert electrode.
• This limitation restricts mechanistic insights into electrochemical reactions involving active electrode surfaces.

Purpose of the Study:

• To demonstrate the utility of an active particle-active electrode system for studying single electrocatalyst properties.
• To investigate the mechanistic details of catalytic reactions and deactivation pathways at the single-entity level.

Main Methods:

• Utilized the electrochemical nanoimpact technique with a platinum (Pt) electrocatalyst adsorbing onto a partially active electrode.
• Analyzed current transients during hydrogen evolution reactions to probe catalyst behavior at different length scales.

Main Results:

• Observed simultaneous measurement of Pt catalyst activity during hydrogen evolution.
• Identified size-dependent phenomena suggesting hydrogen (H) atom intercalation as a catalytic deactivation mechanism.
• Determined that outer-sphere redox probes are unsuitable for characterizing these active systems.

Conclusions:

• An active particle-active electrode configuration provides valuable mechanistic insights into electrochemical reactions.
• The technique is promising for characterizing catalytic nanomaterials individually, particularly for inner-sphere electrochemical reactions.
• Hydrogen atom intercalation is a key deactivation pathway for platinum nanocatalysts in hydrogen evolution.