In recent years there have been several reports on the synthesis of metal nanoparticles with well-controlled size, shape, composition, and atomic arrangement.  This has led to the discovery of new fundamental optical and electronic properties of metal nanoparticles and their applications in optoelectronic devices, sensors, and electrocatalysis.  Nanoparticle stability is critical for applications, since changes in size, shape, composition, or atomic arrangement would lead to changes in their function, which could negatively impact the application they are used for.  An increase in size during electrocatalysis, for example, would likely lower the catalytic activity.  The function of bimetallic nanoparticles depends on the metal composition, but also on the atomic arrangement of the metals in the alloy.  Changes in either could negatively impact their behavior.  Electron microscopies, electron spectroscopies, and x-ray spectroscopies are common tools for characterizing metal nanoparticles and potential changes that occur under certain conditions.  These techniques suffer from being slow, high cost, performed in vacuum instead of the natural environment, and often not sensitive enough to detect the nanoparticles of interest.  Our group developed the use of anodic stripping voltammetry (ASV) over the past several years for the analysis of metal nanoparticle size, composition, atomic arrangement, and aggregation state.  It is excellent for monitoring metal nanoparticle transformations because it is fast, low cost, highly sensitive (&lt;1.0 nm diameter), and able to analyze the nanoparticles in the natural environment when attached to an electrode.  It can easily measure the various ripening or aggregation processes that occur with metal nanoparticles during various chemical and electrochemical treatments.  It can also provide detailed atomic composition and arrangement information for AuCu alloys before and after heat treatment or electrocatalysis experiments.  This can provide a better understanding of the kinetics and mechanisms involved in the metal nanoparticle’s transformation in order to prevent it from occurring in the future.  These high throughput experiments allow the study of many variables and strong statistical analysis to determine the reproducibility and measurement uncertainty, which is often impractical with high vacuum methods.<br/>

Analyzing metal nanoparticle transformations by anodic stripping voltammetry

2019 Spring National Meeting

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