Size and shape dependent melting temperature of metallic nanomaterials

Zhang, Xianhe; Li, Weiguo; Wu, Dong; Deng, Yong; Shao, Jiaxing; Chen, Liming; Fang, Daining

doi:10.1088/1361-648x/aaf54b

Cited by 17 publications

(11 citation statements)

References 73 publications

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“…Both continuous-wave and pulsed lasers have been known to cause dramatic shape change in metal nanoparticles. − These transformations occur due to an increase in the nanoparticle temperature, as a result of the nonradiative decay of the LSPRs into heat. Under high illumination intensities by tightly focused lasers, plasmonic nanoparticles can in fact achieve temperatures as high as their melting points. , However, significant reshaping can occur at milder temperatures well below the melting point of the bulk metal, thanks to the higher mobility of surface metal atoms with respect to bulk and to the low activation energy of diffusion in nanostructures with high curvatures. − Hence, even under mild heating, surface atoms also change their equilibrium positions in order to minimize lattice stress and surface energy . As a result, reshaping and surface reconstruction can occur leading to the formation of pico- and nanocavities and surface protrusions …”

Section: Resultsmentioning

confidence: 90%

Photocatalytic Surface Restructuring in Individual Silver Nanoparticles

et al. 2021

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Light absorption and scattering by metal nanoparticles can drive catalytic reactions at their surface via the generation of hot charge carriers, elevated temperatures, and focused electromagnetic fields. These photoinduced processes can substantially alter the shape, surface structure, and oxidation state of surface atoms of the nanoparticles and therefore significantly modify their catalytic properties. Information on such local structural and chemical change in plasmonic nanoparticles is however blurred in ensemble experiments, due to the typical large heterogeneity in sample size and shape distributions. Here, we use single-particle dark-field and Raman scattering spectroscopy to elucidate the reshaping and surface restructuring of individual silver nanodisks under plasmon excitation and during photocatalytic CO 2 hydrogenation. We show that silver nanoparticles reshape significantly in inert N 2 atmosphere, due to photothermal effects. Furthermore, by collecting the inelastic scattering during laser irradiation in a reducing gas environment, we observe intermittent light emission from silver clusters transiently formed at the nanoparticle surface. These clusters are likely to modify the photocatalytic activity of silver nanodisks and to enable detection of reaction products by enhancing their Raman signal. Our results highlight the dynamic nature of the catalytic surface of plasmonic silver nanoparticles and demonstrate the power of single-particle spectroscopic techniques to unveil their structure–activity relationship both in situ and in real time.

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Section: Resultsmentioning

confidence: 90%

Photocatalytic Surface Restructuring in Individual Silver Nanoparticles

et al. 2021

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“…Although plants are constantly exposed to naturally occurring NPs, exposure to engineered NPs is a new phenomenon and requires sufficient monitoring [2][3][4]. NPs are atomic or molecular aggregates that are characterised by unique physicochemical properties, such as high surface to volume ratio, high antimicrobial reactivity, high photocatalytic activity, and lower melting point, which were directly correlated with their small dimensions of less than 100 nm [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Zinc Oxide and Zinc Oxide Nanoparticles Impact on In Vitro Germination and Seedling Growth in Allium cepa L.

Tymoszuk

Wojnarowicz

2020

Materials

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Zinc oxide nanoparticles (ZnO NPs) are ones of the most commonly manufactured nanomaterials worldwide. They can be used as a zinc fertilizer in agriculture to enhance yielding and to control the occurrence of diseases thanks to its broad antifungal and antibacterial action. The aim of this study was to investigate and compare the effects of ZnO submicron particles (ZnO SMPs) and ZnO NPs on the process of in vitro seed germination and seedling growth in onion (Allium cepa L. ‘Sochaczewska’), and to indicate the potential use of these compounds in onion production. In the experiment, disinfected seeds were inoculated on the modified Murashige and Skoog (MS) medium and poured with ZnO SMP or ZnO NP water suspension, at the concentrations of 50, 100, 200, 400, 800, 1600, and 3200 mg∙L−1. During three successive weeks, the germinating seeds were counted. Germination started most often on the second or third day of in vitro culture. The highest share of germination was recorded for seeds treated with 800 mg∙L−1 ZnO SMPs and ZnO NPs (52% and 56%, respectively). After the application of ZnO SMPs and ZnO NPs at the highest tested concentration (3200 mg∙L−1), the share of germinating seeds was only 19% and 11%, respectively. Interestingly, seedlings obtained from control seeds and seeds treated with ZnO SMPs and ZnO NPs did not differ statistically in terms of length, fresh weight, and dry weight of leaves, and roots. Both ZnO SMPs and ZnO NPs, in the concentration range from 50 to 1600 mg∙L−1, can be used to stimulate the germination process of onion seeds, without negative effects on the further growth and development of seedlings. There were no differences found between the action of ZnO NPs and ZnO SMPs, which suggested that the most important factor influencing seed germination was in fact the concentration of zinc ions, not the particle size.

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“…For instance, Nanda et al, Qi and Wang, and X. Zhang et al predicted that NWs have a slightly higher melting point than spherical NPs based on the liquid drop model in Equation () (Figure 5e). [ 28–30 ]

T_{MP} (d) = T_{mB} (1 - \frac{6 α r}{d})

…”

Section: Resultsmentioning

confidence: 99%

Wettability, Diffusion Behaviors, and Modeling of Ni Nanoparticles and Nanowires in Brazing Inconel 718

et al. 2020

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Ni nanoparticles (NPs) and nanowires (NWs) are compared as brazing filler metals for joining Inconel 718. NWs significantly enhance the strength of brazed joints compared to NP joints (270 MPa). Herein, joints formed with a pure NW pellet and a NW–NP mixed pellet yield average lap shear bonding strengths of 319.2 and 370 MPa, respectively. The experiment displays that the contact angle in brazing with NPs is higher than that with NWs. A modified Hart's equation is also proposed for predicting the effective interdiffusion coefficients of nanomaterials that account for surface diffusion in addition to lattice and grain boundary diffusion. The diffusion coefficients calculated by the modified Hart's equation are consistent with the values determined by Sauer–Friese analysis for NPs, but for NWs, the diffusion coefficients determined by Sauer–Friese are mainly controlled by grain boundary diffusion, significantly higher than those predicted by the modified Hart's equation due to size‐dependent transient liquid phase diffusion. This explains the enhanced brazing strength with NW fillers.

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Size and shape dependent melting temperature of metallic nanomaterials

Cited by 17 publications

References 73 publications

Photocatalytic Surface Restructuring in Individual Silver Nanoparticles

Photocatalytic Surface Restructuring in Individual Silver Nanoparticles

Zinc Oxide and Zinc Oxide Nanoparticles Impact on In Vitro Germination and Seedling Growth in Allium cepa L.

Wettability, Diffusion Behaviors, and Modeling of Ni Nanoparticles and Nanowires in Brazing Inconel 718

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