Theory of Electro-Ionic Perturbations at Supported Electrocatalyst Nanoparticles

Area of Science:

• Electrocatalysis
• Materials Science
• Surface Chemistry

Background:

• Nanoscopic heterogeneities in electrocatalyst composition and structure are critical for material properties.
• Supported electrocatalyst nanoparticles (NPs) are widely used but their interfacial behavior is complex.

Purpose of the Study:

• To develop a model for studying the electrochemical properties of supported electrocatalyst NPs.
• To investigate the influence of support interactions on NP surface charging.
• To understand electronic and ionic equilibration at the NP-support-electrolyte interface.

Main Methods:

• A semiclassical model was developed to simulate supported electrocatalyst nanoparticles.
• The model accounts for correlated electronic and ionic equilibration.
• Model predictions were validated using first-principles calculations.

Main Results:

• The model captures peculiar trends in the surface charging of supported NPs.
• Support-induced perturbations in electronic and ionic charge densities were observed.
• Distinct potentials of zero local electronic and ionic charges were identified, differing by over 0.5 V.

Conclusions:

• Support interactions significantly alter the electronic and ionic charge distributions at the NP surface.
• These alterations lead to substantial differences in potentials of zero charge.
• The findings provide insights into the fundamental behavior of supported electrocatalysts.