Single-entity electrochemistry (SEE) enables research into the electrochemical properties of nanoparticles (NPs) at the individual NP level. Recent studies on active particle-active electrode systems have expanded the scope of SEE measurements, moving beyond the limitations of inert electrode-based methods that rely on distinct NP-electrode catalytic differences, thereby enhancing mechanistic understanding of catalytic reactions. In this study, we investigated SEE signals from Pt NPs colliding with Au ultramicroelectrodes (UME) at elevated potentials where both Pt and Au UME exhibit electrocatalytic activity. Under conditions where Au UME is activated for hydrazine oxidation, distinctive combined spike and staircase current responses were observed. SEE signals exhibited varied shapes depending on pH and hydrazine concentration. Analyzing these variations provided insights into changes in reaction mechanisms according to pH and hydrazine concentration.
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http://dx.doi.org/10.1039/d4nr02942a | DOI Listing |
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November 2024
School of Chemistry, Trinity College Dublin, Dublin, 2, Ireland.
N-doped graphene oxides (GO) are nanomaterials of interest as building blocks for 3D electrode architectures for vanadium redox flow battery applications. N- and O-functionalities have been reported to increase charge transfer rates for vanadium redox couples. However, GO synthesis typically yields heterogeneous nanomaterials, making it challenging to understand whether the electrochemical activity of conventional GO electrodes results from a sub-population of GO entities or sub-domains.
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November 2024
Bragg Centre for Materials Research, University of Leeds, LS2 9JT, UK.
Nanopores are emerging as a powerful tool for the analysis and characterization of nanoparticles at the single entity level. Here, we report that a PEG-based polymer electrolyte present inside the nanopore enables the enhanced detection of nanoparticles at low ionic strength. We develop a numerical model that recapitulates the electrical response of the glass nanopore system, revealing the response to be sensitive to the position of the polymer electrolyte interface.
View Article and Find Full Text PDFAnal Chim Acta
November 2024
School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, PR China; Analytical and Testing Center, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, PR China.
Background: Electrochemiluminescence (ECL) is an electrochemically induced process in which radicals generated at the electrode surface undergo exergonic electron transfer reaction to form excited states and luminesce. ECL, with high sensitivity and superior spatiotemporal control, has been widely applied in bioanalysis and light-emitting devices. The ECL signal of rubrene (Rub) was observed in Rub/TPrA oil-in-water (o/w) emulsions, which was inconsistent with the theory of ion-transfer coupled electron-transfer in Rub emulsion droplets, and the conventional ECL mechanism in Rub/TPrA system couldn't explain this phenomenon.
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October 2024
Department of Chemistry - Ångström, Uppsala University, 75120 Uppsala, Sweden.
Single-entity electrochemistry (SEE) is an emerging field within electrochemistry focused on investigating individual entities such as nanoparticles, bacteria, cells, or single molecules. Accurate identification and analysis of SEE signals require effective data processing methods for unbiased and automated feature extraction. In this study, we apply and compare two approaches for step detection in SEE data: discrete wavelet transforms (DWT) and convolutional neural networks (CNN).
View Article and Find Full Text PDFAnal Chem
November 2024
Department of Advanced Materials Chemistry, Korea University, Sejong 30019, Korea.
Single-entity electrochemistry has gained significant attention for the analysis of individual cells, nanoparticles, and droplets, which is leveraged by robust electrochemical techniques such as chronoamperometry and cyclic voltammetry (CV) to extract information about single entities, including size, kinetics, mass transport, etc. For an in-depth understanding such as dynamic interaction between the electrode and a single entity, the unconventional fast electrochemical technique is essential for time-resolved analysis. This fast experimental technique is unfortunately hindered by a substantial nonfaradaic response.
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