Unique Voltammetry of Silver Nanoparticles: From Single Particle to Aggregates

Abstract

Understanding the electrooxidation process of metal nanoparticles (NPs) is very important because they have showed wide applications in electrocatalysis, sensing, and nanoelectronics. In this letter, we designed a strategy to investigate the anodic stripping voltammetry (ASV) of silver oxidation at single NP level and aggregation state by using gold single nanoelectrodes (SNEs) and ultramicroelectrodes. Results showed that the ASV peak potential and shape were significantly affected by the diameter and aggregation degree of the Ag NPs: symmetrical-peak shape, two-peak shape, and asymmetrical-peak shape appeared when Ag NPs changed from the single particle state to the large-aggregation state, and size-dependent ASVs for Ag NPs oxidation were also observed. These findings can help us deeply understand the metal NPs oxidation process and will benefit the related applications.

Current Methods and Prospects for Analysis and Characterization of Nanomaterials in the Environment

“…In voltammetry measurements, metal-based nanoparticles produce electrochemical signals at different electrode potentials than corresponding dissolved metal species, which can be translated to the presence and concentration of nanomaterials. Voltammetric techniques, such as anodic stripping voltammetry and adsorptive cathodic stripping voltammetry, have been explored to detect a variety of nanomaterials, including metal chalcogenides (e.g., Cu x S, FeS, , and HgSe) and metallic (e.g., Au and Ag) , NPs, in artificial and natural aqueous matrices. However, the voltammetric signal is highly dependent on the composition of the aqueous matrix, including the type and composition of the electrolyte as well as the presence of electroactive dissolved metals, inorganic ligands (e.g., sulfide ions), and natural organic matter (NOM). , Moreover, the analyte selectivity of voltammetric measurement is relatively low.…”

Recent advances in silver nanoparticle-based electrochemical sensors for determining organic pollutants in water: a review

“…The third type of electrochemical aggregation sensor is based on signal inhibition/amplification, where nonaggregated AgNPs signal is inhibited and aggregated AgNPs signal, with a positive potential shift, is amplified 110 . The positive potential shift after the induced AgNPs aggregation is attributed to diminished surface area-to-volume ratio [153][154] .…”

Size-Dependent Electrochemistry and Electrocatalysis at Single Au@Pt Bimetallic Nanoparticles

“…Metal nanoparticles (NPs), especially bimetallic NPs, have attracted much attention in recent years due to their distinctive physical and chemical properties, which have resulted in their wide use as catalysts in energy-related field, chemical synthesis, and chemo-/biosensing. − Many works have shown that the electrochemical and electrocatalytic properties of NPs are extremely dependent on their sizes and surface structure. ,− , For example, Zamborini’s group reported a series of works about the size-dependent voltammetry of Ag/Au NPs and their aggregates’ oxidation using anodic stripping voltammetry. ,, Koper’s group investigated the influence of hydrazine-induced aggregation for the electrochemical response between single NPs and aggregates . However, most of the published results of the study on NPs have been obtained from a large ensemble of particles, and the details of the reaction mechanism have always been masked in ensemble-averaged measurements …”

“…The stochastic collision electrochemistry provided a new insight to monitor the single NPs/molecules electrochemical process, − but the current spikes recorded in a short time using stochastic collision cannot give more information of the electrochemistry and electrocatalysis . Recently, our group investigated the size-dependent properties of single Au NPs, single Ag nanoelectrodes, and single Ag NPs. ,− It is well-known that the properties of bimetallic NPs often differ markedly from either of the constituent metals, and the mixtures frequently exhibit enhanced catalytic stability, activity, or selectivity, which results in their wide use in catalysis and sensing fields. , Therefore, it is necessary to investigate the electrochemistry and electrocatalysis of bimetallic single NPs.…”

“…1−12 Many works have shown that the electrochemical and electrocatalytic properties of NPs are extremely dependent on their sizes and surface structure. 1,[3][4][5]13 For example, Zamborini's group reported a series of works about the size-dependent voltammetry of Ag/Au NPs and their aggregates' oxidation using anodic stripping voltammetry. 1,3,4 Koper's group investigated the influence of hydrazine-induced aggregation for the electrochemical response between single NPs and aggregates.…”