In situ STEM/SEM study of the coarsening of nanoporous gold

El‐Zoka, Ayman A.; Newman, R.C.; Perović, D. D.

doi:10.1016/j.actamat.2018.09.002

Acta Materialia

2019

DOI: 10.1016/j.actamat.2018.09.002

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In situ STEM/SEM study of the coarsening of nanoporous gold

Ayman A. El‐Zoka

R.C. Newman

D. D. Perović

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Cited by 26 publications

(20 citation statements)

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“…Here, we observe that the nanowire collapses on itself and most of the pores disappear. This behavior is also reported with a decrease in the nanowires diameter and pore size when increasing the annealing temperature . A zoom was realized on a nanopore of the previous TEM images (Figure a).…”

supporting

confidence: 80%

“…Between 350 and 577 °C, an increase in a pore size and thickening of the wall are detected. This temperature scale is in accordance with the one reported previously for bulk NPG . To evaluate the pore size, the ligament size, the wall thickness, and the diameter of the nanowire, a statistical study was performed on the acquired STEM images of a single nanowire (Figure b,c).…”

supporting

confidence: 77%

“…[14] Experimentally, the coarsening of ligaments has been investigated by using X-ray nanotomography, [28] micro diffraction, [25] positron annihilation, [29] small-angle X-ray scattering (SAXS), [14] scanning electron microscopy (SEM) experiments, [22,30] through thermal conductivity measurements, [20] and by transmission electron microscopy (TEM) experiment. [31] However, all these techniques give information at a macroscopic scale compared with the relevant scale of the phenomena we want to study. Moreover, the preparation of the sample can induce modification inside the nanoporous structure.…”

mentioning

confidence: 99%

“…This temperature scale is in accordance with the one reported previously for bulk NPG. [31] To evaluate the pore size, the ligament size, the wall thickness, and the diameter of the nanowire, a statistical study was performed on the acquired STEM images of a single nanowire (Figure 1b,c). The ligament size, indeed, does not include the size of the ligament corresponding to the wall.…”

mentioning

confidence: 99%

“…This behavior is also reported with a decrease in the nanowires diameter and pore size when increasing the annealing temperature. [31,36,39] A zoom was realized on a nanopore of the previous TEM images (Figure 4a). Between 25 and 300 C, a slight decrease in the pore size is observed.…”

mentioning

confidence: 99%

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Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Chauvin

Molina‐Luna

Ding

et al. 2019

Physica Rapid Research Ltrs

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Over the past decades, porous gold has been used in plenty of applications such as catalysis or sensor detection. However, the nanoscale size of both the ligaments and pores makes such material very sensible to temperature. Indeed, the increase in temperature induces coarsening of the structure which can be detrimental for various applications. In this context, understanding of the coarsening on nanoporous gold (NPG) is crucial. In this communication, in situ scanning transmission electron microscopy (STEM) analysis of coarsening is reported by considering the nanosize of the dealloyed sample in dependence on the annealing of NPG nanowire. This study is performed by the in situ STEM of NPG nanowires after annealing between 25 and 600 °C with two different feature ratios (i.e., ligament/pore size) of 0.6 and 1.4. Herein, for the first time, an experimental demonstration is carried out for the two different behaviors of morphology evolution with temperature, corresponding to ligament pinch‐off and collapsing of nanoporous materials, which have been highlighted by simulations in the literature.

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supporting

confidence: 80%

supporting

confidence: 77%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Chauvin

Molina‐Luna

Ding

et al. 2019

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

show abstract

Boosting the H₂–D₂ Exchange Activity of Dilute Nanoporous Ti–Cu Catalysts through Oxidation–Reduction Cycle–Induced Restructuring

et al. 2023

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The use of nanoporous metals as catalysts has attracted significant interest in recent years. Their high‐curvature, nanoscale ligaments provide not only high surface area but also a high density of undercoordinated step edge and kink sites. However, their long‐term stability, especially at higher temperatures, is often limited by thermal coarsening and the associated loss of surface area. Herein, it is demonstrated that the nanoscale morphology of nanoporous Cu can be regenerated by applying oxidation/reduction cycles at 250 °C. Specifically, the morphological evolution and H2 dissociation activity of hierarchical nanoporous Cu catalysts doped with Ti during structural rearrangement triggered by oxidative and reductive atmospheres at elevated temperatures are studied. In addition to coarsening of the structure at elevated temperatures, oxidation at 400 °C causes an expansion of the ligaments. Subsequent reduction at 400 °C leads to the formation of particles and a drop in the H2 dissociation activity compared the fresh catalyst. However, performing the redox cycle at 250 °C reverses coarsening and boosts the H2 dissociation activity for the hydrogen–deuterium (H2–D2) reaction. Herein, the possibility to reverse coarsening is demonstrated, thereby mitigating the loss of activity frequently observed in nanoporous catalysts.

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In Situ Temperature Dependent Optical Characterization and Modeling of Dealloyed Thin‐Film Nanoporous Gold Absorbers

Ramesh

Niauzorau

Sampath

et al. 2022

Advanced Optical Materials

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Nanostructured noble metals such as gold exhibit unique size‐dependent plasmonic and optical properties which is an enabling factor for designing nanophotonic devices. However, for its deployment in high temperature applications such as solar thermal energy harvesting and optothermal conversion, it requires understanding of its temperature dependent optical properties. This paper investigates the in situ specular reflectance of nanoporous gold (NPG) thin films in the wavelength range between 400 and 1000 nm at temperatures ranging from 25 to 500 °C via a home‐built fiber‐based optical spectrometer. During heating, the NPG's ligaments coalesce from an initial size of 39 ± 12 nm to a final size of up to 299 ± 114 nm, and its ligament scales with temperature closely matching an Arrhenius dependence. The surface roughness of NPG is empirically correlated to ligament size and temperature to allow for the theoretical prediction of the relative specular reflectance using scattering coefficients and effective medium theory which closely matches the experimental results. These results represent a step forward in using in situ optical spectroscopic methods to monitor the ligament size evolution of NPG thin‐films and to understand its stability and optical properties for applications at elevated temperatures.

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In situ STEM/SEM study of the coarsening of nanoporous gold

Cited by 26 publications

References 38 publications

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Boosting the H₂–D₂ Exchange Activity of Dilute Nanoporous Ti–Cu Catalysts through Oxidation–Reduction Cycle–Induced Restructuring

In Situ Temperature Dependent Optical Characterization and Modeling of Dealloyed Thin‐Film Nanoporous Gold Absorbers

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In situ STEM/SEM study of the coarsening of nanoporous gold

Cited by 26 publications

References 38 publications

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Study of the Coarsening of Nanoporous Gold Nanowires by In Situ Scanning Transmission Electron Microscopy During Annealing

Boosting the H2–D2 Exchange Activity of Dilute Nanoporous Ti–Cu Catalysts through Oxidation–Reduction Cycle–Induced Restructuring

In Situ Temperature Dependent Optical Characterization and Modeling of Dealloyed Thin‐Film Nanoporous Gold Absorbers

Contact Info

Product

Resources

About

Boosting the H₂–D₂ Exchange Activity of Dilute Nanoporous Ti–Cu Catalysts through Oxidation–Reduction Cycle–Induced Restructuring