High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

doi:10.1038/srep21434

Cited by 19 publications

(14 citation statements)

References 46 publications

(92 reference statements)

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“…The envelope function, f e ( r , d ), is defined as follows: Here, r is the atom–atom distance in Å, and d is the mean particle size in Å. H is a Heaviside step function which ensures that the envelope function goes to zero for r > d . This function has been successfully used to estimate the mean particle size as well as particle size distribution of nanosized particles using PDF. , Even though our samples contain particles at the micron scale, the envelope function gives us an estimate of the crystallite size for our gels. Hence, these data show that the C-(N)-A-S-H gel formed in AAS is predominantly amorphous as opposed to nanocrystalline, and the small amount of long-range ordering that is present is limited in intensity and distance (i.e., 25 Å).…”

Section: Resultsmentioning

confidence: 99%

Nanoscale Ordering and Depolymerization of Calcium Silicate Hydrates in the Presence of Alkalis

et al. 2019

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Increasing cement production and its substantial contribution to anthropogenic CO2 emissions (∼5–8%) have led to the pursuit of alternative, sustainable cements. These sustainable cements often contain non-negligible amounts of alkalis (Na or K) which significantly influence the resulting material’s performance. However, the precise mechanism(s) by which the atomic structure and thermodynamic stability of the primary binder phase is altered remains unknown. Here, we have synthesized 45 pure sodium-substituted calcium-(alumino-)silicate-hydrate (C-(N)-(A)-S-H) gels using a wide range of alkali concentrations (0.1–5 M). We report that the addition of higher levels of alkalis during synthesis of the gels results in a systematic reduction in basal spacing, mean silicate chain lengths, and, most importantly, degree of silicate polymerization. These changes to the gel’s extent of polymerization, confirmed by X-ray pair distribution function and nuclear magnetic resonance (NMR) spectroscopy, may have implications on the long-term durability and stability of sustainable cements activated with high levels of alkali hydroxides or silicates. Finally, we compare the nanoscale ordering (between ∼5 and 40 Å) of our synthetic gels with real gels found in commercial systems and find that their nanoscale ordering is significantly different, where the real gels tend to be considerably more disordered.

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Section: Resultsmentioning

confidence: 99%

Nanoscale Ordering and Depolymerization of Calcium Silicate Hydrates in the Presence of Alkalis

et al. 2019

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“…A majority of NP species studied so far were found to be stiffer than bulk including but not limited to Au, Ag, Pt, TiO 2 , TiC, Fe 2 O 3 , CoFe 2 O 4 , CeO 2 , PbS, and BaF 2 . ,,,,,− Nobel metal NPs are the common subjects in material research due to their ease of synthesis and ambient stability. As reported by Gu et al, high-pressure XRD measurements revealed a significantly higher B 0 of 290 GPa of 30 nm gold NPs over the bulk value of 170 GPa as well as a B 0 of silver increased noticeably from 116 to 140 GPa .…”

Section: Properties and Applications Of Nps Under Pressurementioning

confidence: 99%

Pressure Induced Nanoparticle Phase Behavior, Property, and Applications

et al. 2019

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Nanoparticle (NP) high pressure behavior has been extensively studied over the years. In this review, we summarize recent progress on the studies of pressure induced NP phase behavior, property, and applications. This review starts with a brief overview of high pressure characterization techniques, coupled with synchrotron X-ray scattering, Raman, fluorescence, and absorption. Then, we survey the pressure induced phase transition of NP atomic crystal structure including size dependent phase transition, amorphization, and threshold pressures using several typical NP material systems as examples. Next, we discuss the pressure induced phase transition of NP mesoscale structures including topics on pressure induced interparticle separation distance, NP coupling, and NP coalescence. Pressure induced new properties and applications in different NP systems are highlighted. Finally, outlooks with future directions are discussed.

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“…It offers several advantages with respect to the use of energies in the range 10-30 keV. First, the enlarged range of Q range, where Q = (4πsinθ)/λ) is the scattering wave vector [116]. Second, the fast decay of the photoelectric cross-section with energy above the K-edge results in vanishing absorption corrections.…”

Section: Conclusion and Perspectivementioning

confidence: 99%

Using In-Situ Laboratory and Synchrotron-Based X-ray Diffraction for Lithium-Ion Batteries Characterization: A Review on Recent Developments

et al. 2020

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Renewable technologies, and in particular the electric vehicle revolution, have generated tremendous pressure for the improvement of lithium ion battery performance. To meet the increasingly high market demand, challenges include improving the energy density, extending cycle life and enhancing safety. In order to address these issues, a deep understanding of both the physical and chemical changes of battery materials under working conditions is crucial for linking degradation processes to their origins in material properties and their electrochemical signatures. In situ and operando synchrotron-based X-ray techniques provide powerful tools for battery materials research, allowing a deep understanding of structural evolution, redox processes and transport properties during cycling. In this review, in situ synchrotron-based X-ray diffraction methods are discussed in detail with an emphasis on recent advancements in improving the spatial and temporal resolution. The experimental approaches reviewed here include cell designs and materials, as well as beamline experimental setup details. Finally, future challenges and opportunities for battery technologies are discussed.

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High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

Cited by 19 publications

References 46 publications

Nanoscale Ordering and Depolymerization of Calcium Silicate Hydrates in the Presence of Alkalis

Nanoscale Ordering and Depolymerization of Calcium Silicate Hydrates in the Presence of Alkalis

Pressure Induced Nanoparticle Phase Behavior, Property, and Applications

Using In-Situ Laboratory and Synchrotron-Based X-ray Diffraction for Lithium-Ion Batteries Characterization: A Review on Recent Developments

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