Please refer to published version for the most recent bibliographic citation information. If a published version is known of, the repository item page linked to above, will contain details on accessing it.
As part of the revolution in electrochemical nanoscience, there is growing interest in using electrochemistry to create nanostructured materials and to assess properties at the nanoscale. Herein, we present a platform that combines scanning electrochemical cell microscopy with ex situ scanning transmission electron microscopy to allow the ready creation of an array of nanostructures coupled with atomic-scale analysis. As an illustrative example, we explore the electrodeposition of Pt at carbon-coated transmission electron microscopy (TEM) grid supports, where in a single high-throughput experiment it is shown that Pt nanoparticle (PtNP) density increases and size polydispersity decreases with increasing overpotential (i.e., driving force). Furthermore, the coexistence of a range of nanostructures, from single atoms to aggregates of crystalline PtNPs, during the early stages of electrochemical nucleation and growth supports a nonclassical aggregative growth mechanism. Beyond this exemplary system, the presented correlative electrochemistry–microscopy approach is generally applicable to solve ubiquitous structure–function problems in electrochemical science and beyond, positioning it as a powerful platform for the rational design of functional nanomaterials.
We report an enhancement of up to 85% in the photocurrent generated from a bismuth vanadate photoanode through the prior deposition of mass-selected Ti nanoclusters onto the semiconductor surface. We studied the effect of a variety of cluster sizes, deposited at the same density and with the same energy (1.5 keV per cluster), over the surface of separate BiVO 4 photoanodes in a cluster beam source. Using mass-selected clusters of a narrow size distribution, we were able to reveal that the photocurrent is strongly dependent on the cluster size (in the size regime examined), leading to an increase of up to 85% in the photocurrent for Ti 2000AE54 clusters. Remarkably the quantities of metal used to achieve such an enhancement are on the 2.8 Â 10 À7 g cm À2 level, resulting from the optimum density which is approximately 0.4 monolayers. This work highlights the importance of submonolayer surface treatments, using accurate mass-selected nanoclusters, for the modification of semiconductor surfaces in order to improve the interfacial charge transfer properties. † Electronic supplementary information (ESI) available: Mass spectrum showing no target oxidation; examples of processed STEM images for Ti 2000 and Ti 8000 ; XPS survey for cluster modied BiVO 4 ; J-V curve for Ti 923 modied BiVO 4 ; J-V for Ti 8000 modied BiVO 4 ; stability JV curves for BiVO 4 under white light and blue light illumination; J-V curve for cluster modied FTO control experiment. See
Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au(SCHCHPh) provided by two different research groups. The MP Au clusters were "weighed" by the atom counting method, based on their integrated intensities in the high angle annular dark field (HAADF) regime and calibrated exponent of the Z dependence. For atomic structure analysis, we compared experimental images of hundreds of clusters, with atomic resolution, against a variety of structural models. Across the size range 123-151 atoms, only 3% of clusters matched the theoretically predicted Au(SR) structure, while a large proportion of the clusters were amorphous (i.e. did not match any model structure). However, a distinct ring-dot feature, characteristic of local icosahedral symmetry, was observed in about 20% of the clusters.
Polyaniline (PAn) films can be used in an electrochemical and optical combination system to amplify the optical signal for dissolved oxygen (DO) detection. To further improve the sensitivity of PAn film to DO, an oxygen‐sensitive molecule, Fe(III) meso‐tetera (4‐sulfonatophenyl) porphyrin (FeTSPP) is incorporated into PAn during the film generation. Results show that, after incorporating FeTSPP into the PAn matrix, both optical and potentiometric responses to DO are improved. The optimal optical signal is obtained under the application of −2.5 μA to the modified electrode. Under this applied current, both optical and potentiometric signals show linear relations with the DO concentration within the range of 0.00–4.63 mg L−1, and the sensitivities for optical and potentiometric signals are 4.18 grayscale units mg−1 L and 13.39 mV mg−1 L, respectively.
SummaryIn this study, size‐selected platinum (Pt) nanoclusters were imaged with aberration‐corrected scanning transmission electron microscopy in high‐angle annular dark field (HAADF) mode. For image analysis, a relatively simple macro program was developed by making the use of existing ImageJ plug‐ins. The macro allows effectively for assessing criterions chosen for intensity threshold and filter blurring factors. It can extract the integrated HAADF intensity, peak intensity and projected area of the clusters. Here, the effects of magnification and objective lens defocus on nanocluster measurement were investigated. It was found that the integrated HAADF intensity of Pt clusters is a more robust sample descriptor than the peak intensity and the projected area. The macro program developed is freely available.Lay DescriptionMeasuring precisely the size of nanoclusters plays an important role in the investigation of nanocluster‐based material systems. Aberration‐corrected scanning transmission electron microscopy (STEM) is one of the most powerful tools to extract the size of clusters directly from their images. In this study, we developed a macro program based on existing ImageJ plug‐ins, allowing easy‐assessment of criterions chosen for image intensity threshold and filter blurring factors. It can be used to extract the integrated intensity, peak intensity, and projected area of the clusters for size determination. Using the program, we investigated the effects of magnification and objective lens defocus on measurements performed on size‐selected platinum (Pt) nanoclusters, and found that the integrated intensity of Pt clusters is a more robust sample descriptor than the peak intensity and the projected area. The macro developed allows a rapid assessment of factors affecting the accuracy with which size information can be obtained from clusters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.