Observing iridium oxide (IrO(x)) single nanoparticle collisions at ultramicroelectrodes

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Analytical Chemistry

Background:

• Electrochemical detection of nanoparticles is crucial for various applications.
• Understanding nanoparticle-electrode interactions is key for sensitive detection.
• Iridium oxide nanoparticles (IrO(x) NPs) have unique catalytic properties.

Purpose of the Study:

• To develop a sensitive electrochemical method for detecting single IrO(x) NPs.
• To characterize the electrochemical response of single IrO(x) NP collisions.
• To investigate the influence of electrode surface modification on detection reproducibility.

Main Methods:

• Utilized a sodium borohydride (NaBH(4))-treated platinum ultramicroelectrode (UME).
• Monitored transient current changes upon single IrO(x) NP collisions.
• Analyzed current spikes generated by electrocatalytic water oxidation.

Main Results:

• Observed distinct current spikes (blips) for individual IrO(x) NP events.
• Found spike frequency proportional to NP concentration.
• Demonstrated peak current dependence on applied potential.
• Highlighted the importance of NaBH(4) treatment for reproducible results.

Conclusions:

• Single IrO(x) NP collisions can be detected electrochemically via transient current spikes.
• The method offers high sensitivity and potential for quantitative analysis.
• Electrode surface modification is critical for reliable nanoparticle detection.