Plasmonic Scattering Imaging of Interfacial Electrochemistry on Single Nanoparticles

Abstract

Directly visualizing surface chemical dynamics in solution requires the in situ, real-time monitoring of local reactions, a major methodological challenge. Here, we introduce electrochemical plasmonic scattering microscopy, an electrochemical surface plasmon resonance (SPR) scattering technique that enables dynamic imaging of interfacial electrochemistry. By replacing conventional reflection-based detection with scattering imaging while maintaining a sharp SPR response, our approach preserves high surface sensitivity and achieves exceptional optical contrast and spatial resolution. Crucially, the method exhibits substantially reduced sensitivity to surface‑charging interference of the sensing film compared with conventional SPR. This capability enables wide-field imaging of interfacial electrochemical processes in real time, allowing us to resolve cyclic voltammograms from individual nanoparticles. We further demonstrate the direct visualization of local reaction dynamics, uncovering previously unknown heterogeneity in surface reactions along single noble metal nanowires. We present a convenient and straightforward method that transforms conventional, widely used SPR platforms into a powerful and user-friendly tool for imaging the interfacial electrochemistry of single nanoparticles.