Unraveling Diffusion Dynamics and Electrocatalytic Behavior of Single Nanocatalysts via Transient Electrogenerated Chemiluminescence Microscopy

Single-particle electrochemistry (SPE) is essential for uncovering the electrochemical behavior and underlying mechanisms of individual nanomaterials. However, conventional approaches often overlook dynamic interactions between nanocrystals and the conductive substrate, leading to significant interference from substrate-induced concentration gradients and electron-transfer perturbations. Here, we address this challenge by developing transient electrogenerated chemiluminescence microscopy (ECLM) to visualize the diffusion dynamics and electrocatalytic behavior of single PtAu-loaded carbon nanoparticles. ECL imaging quantitatively analyzes reaction kinetics at single nanocatalysts and reveals the diffusion dynamics significantly influenced by conductive substrate. To mitigate substrate-induced interference and improve measurement accuracy, we introduce the pulse-clean cycle technique (PCCT). By applying millisecond-level potential pulses, PCCT achieves high temporal resolution and captures rapid catalytic events with statistical reliability. This work bridges the gap between single-particle imaging and precise kinetic quantification, offering a robust platform for probing nanoscale electrocatalytic transients, understanding nanostructure-activity relationships, and guiding the rational design of advanced nanocatalysts.