Nanoscale Electron Transfer Variations at Electrocatalyst-Electrolyte Interfaces Resolved by in Situ Conductive...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Understanding spatial variations in material properties at the solid-electrolyte interface is crucial for designing efficient electrocatalysts.
• Current methods often lack the nanoscale resolution to probe simultaneous electrical, chemical, and morphological characteristics in situ.

Purpose of the Study:

• To introduce and demonstrate a correlative atomic force microscopy (AFM) approach for simultaneous nanoscale probing of interfacial properties.
• To investigate the structure-property relationships of a bimetallic copper-gold system during CO2 electroreduction under varying conditions.

Main Methods:

• Correlative atomic force microscopy (AFM) was employed to simultaneously measure electrical conductivity, chemical-frictional properties, and morphology.
• In situ measurements were performed in air, water, and bicarbonate electrolyte to analyze a copper-gold bimetallic system.
• Current-voltage curves and frictional imaging were utilized to assess interfacial behavior at the nanoscale.

Main Results:

• Resistive copper oxide (CuO) islands were identified, correlating with local current contrasts.
• Frictional imaging revealed changes in hydration layer molecular ordering when transitioning from water to electrolyte.
• Nanoscale current mapping on gold showed resistive grain boundaries and electrocatalytically inactive adlayer regions, with reduced currents linked to increased friction.

Conclusions:

• The study demonstrates the capability of correlative AFM to provide in situ nanoscale insights into electrocatalyst interfacial properties.
• Electrolyte composition and adsorbed species significantly influence interfacial charge transfer and molecular ordering.
• These findings support the development of in situ structure-property relationships for catalysis and energy conversion research.