Particle Impact Electrochemistry

Abstract

Experiments involving collisions between a single entity and the electrode surface have become an active area of research. The electrochemical contribution of individual nanoparticles (NPs), enzymes, and other entities, such as aggregates or agglomerates, can be determined using particle impact experiments. Destructive nanoimpact experiments of materials, such as Ag, and the electrocatalytic amplification (ECA) are used to detect the NP/electrode interactions. This review covers the seminal work, critical theoretical studies, and some recent applications. The applications to electrocatalysis include measurements of electron transfer rate constants on individual nanoparticles. Applications in analytical chemistry have allowed the detection of nonelectroactive species by detecting the collisions of soft materials, e.g. micellar suspensions and proteins have increased the technique's analytical possibilities. With ECA, NPs can be used as tags for the electrochemical detection of bioanalytes such as DNA, proteins, and liposomes. The theory of ECA collisions, including frequency of collision and the size of the electrochemical current transients, are also covered. For nanoimpacts, the charge measured during a NP electrolysis, such as Ag NP, is used to detect the NP. Measurements of NP diameter are possible, but limitations to this analysis are covered. The electron transfer studies to the electrolysis of Ag and of metal oxides are discussed. Finally, key experimental instrumentations are discussed, including instrumentation techniques for the small currents inherent to single NP measurement. The effect of filtering, instrumentations rise time, and sampling frequency are also covered.

Why Measure Particle-by-Particle Electrochemistry? A Tutorial and Perspective

“…There are also reports that have shown nano-impact events through the collisions of "soft" particles (micelles) with an UME and an applied electrochemical potential. [28][29][30][46][47][48][49][50] There are several reviews on the subject, [51][52][53][54][55][56][57][58][59][60] but in this paper, we focus on introducing critical concepts and techniques related to nanoparticles or other entities colliding with a working UME. Other modes that are not addressed in depth here, are based on scanning probes techniques and instrumentation, such as such scanning electrochemical microscopy, SECM, [23,24] and scanning electrochemical cell microscopy, SECCM.…”

Single Entity Electrocatalysis

“…Stochastic (nano)electrochemistry is also called (nano)impact electrochemistry, collision electrochemistry, (nano)particle impact, or single entity electrochemistry and has been thoroughly reviewed in the literature over the last 5 years. − This is a method of electrochemically detecting single things, one at a time. These “things” include insulating polystyrene beads, nanodroplets loaded with an electroactive species, catalytic metal nanoparticles, and bio-entities (e.g., bacteria, viruses) .…”