Issue 3, 2017

Impact and oxidation of single silver nanoparticles at electrode surfaces: one shot versus multiple events

Abstract

Single nanoparticle (NP) electrochemical impacts is a rapidly expanding field of fundamental electrochemistry, with applications from electrocatalysis to electroanalysis. These studies, which involve monitoring the electrochemical (usually current–time, It) response when a NP from solution impacts with a collector electrode, have the scope to provide considerable information on the properties of individual NPs. Taking the widely studied oxidative dissolution of individual silver nanoparticles (Ag NPs) as an important example, we present measurements with unprecedented noise (< 5 pA) and time resolution (time constant 100 μs) that are highly revealing of Ag NP dissolution dynamics. Whereas Ag NPs of diameter, d = 10 nm are mostly dissolved in a single event (on the timescale of the measurements), a wide variety of complex processes operate for NPs of larger diameter (d ≥ 20 nm). Detailed quantitative analysis of the It features, consumed charge, event duration and impact frequency leads to a major conclusion: Ag NPs undergo sequential partial stripping (oxidative dissolution) events, where a fraction of a NP is electrochemically oxidized, followed by the NP drifting away and back to the tunnelling region before the next partial stripping event. As a consequence, analysis of the charge consumed by single events (so-called “impact coulometry”) cannot be used as a general method to determine the size of colloidal NPs. However, a proper analysis of the It responses provides highly valuable information on the transient physicochemical interactions between NPs and polarized surfaces.

Graphical abstract: Impact and oxidation of single silver nanoparticles at electrode surfaces: one shot versus multiple events

Supplementary files

Article information

Article type
Edge Article
Submitted
02 Sep 2016
Accepted
26 Oct 2016
First published
12 Dec 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2017,8, 1841-1853

Impact and oxidation of single silver nanoparticles at electrode surfaces: one shot versus multiple events

J. Ustarroz, M. Kang, E. Bullions and P. R. Unwin, Chem. Sci., 2017, 8, 1841 DOI: 10.1039/C6SC04483B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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