Mapping electroactivity at individual catalytic nanostructures using high-resolution scanning...

Area of Science:

• Electrochemistry
• Nanotechnology
• Surface Science

Background:

• Mapping surface electroactivity at the nanoscale is crucial for understanding nanomaterials.
• Existing techniques often lack the resolution or correlative topographical information needed for detailed analysis.

Purpose of the Study:

• To demonstrate the capability of combined scanning electrochemical-scanning ion conductance microscopy (SECM-SICM) for high-resolution surface electroactivity mapping.
• To correlate electrochemical activity with precise topographical data at the 100-150 nm scale.
• To validate the technique on model systems and apply it to nanostructured substrates.

Main Methods:

• Utilized dual-channel capillary probes with integrated SICM and SECM electrodes.
• Employed approach curve analysis and imaging in feedback and substrate generation-tip collection modes.
• Applied SECM-SICM to image gold nanodisk arrays and platinum nanosphere ensembles.

Main Results:

• Successfully mapped electroactivity of individual features at 100-150 nm scale.
• Achieved correlation between surface activity and accurate topographical information.
• Demonstrated imaging of isolated gold nanodisks and detection of oxygen consumption at platinum nanoparticles.

Conclusions:

• SECM-SICM is valuable for low-current amperometric imaging of nanosystems.
• The technique provides a step towards quantitative measurement of electrokinetics at the single particle level.
• High-resolution correlative electrochemical and topographical imaging is achievable.