In situ EELS study of dehydration of Al(OH)3 by electron beam irradiation

Jiang, Nan; Spence, John C. H.

doi:10.1016/j.ultramic.2010.11.004

Cited by 22 publications

(18 citation statements)

References 22 publications

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“…The peaks around 541, 549 and 560 eV in as-received alumina (spectrum 1), hydrated alumina (spectrum 2) and ethanol-modified alumina (spectrum 3) match the reported characteristic peaks for γ-Al 2 O 3 29. The hydroxylation of the as-received (spectrum1) and hydrated samples (spectrum2) is evidenced by the presence of peaks around 531 eV, which is, reportedly, one of the fingerprints for Al(OH) 3 30. The absence of this hydroxylated peak in ethanol-modified sample confirms the effective removal of the initial hydration layer via ethanol treatment.…”

Section: Discussionsupporting

confidence: 75%

“…Figure 5 (A) presents the spectra from as-received alumina ( 1 ), hydrated alumina ( 2 ), ethanol-modified alumina ( 3 ), reference γ-Al 2 O 3 29 (4) , reference α-Al(OH) 3 30 (5) and reference AlO(OH)31 (6) . Figure 5 (B) shows peak fitting analysis of the acquired data and details of peak fitting are given in Table SI 1.…”

Section: Resultsmentioning

confidence: 99%

“…Notably, Lefèrve and co-authors reported on hydroxylation of γ-Al 2 O 3 and formation of Al(OH) 3 and AlO(OH) upon the exposure to water37. The spectra acquired on as-received alumina (spectrum 1), hydrated alumina (spectrum 2) and ethanol-modified alumina (spectrum 3) are compared to those of reference materials reported in the literature, namely γ-Al 2 O 3 (spectrum 4)29, Al(OH) 3 (spectrum 5)30 and AlO(OH) (spectrum 6)31, respectively. The peak fitting analysis presented in Fig.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

Firlar

Çınar

Kashyap

et al. 2015

Sci Rep

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Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions. We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. Our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles.

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Section: Discussionsupporting

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

Firlar

Çınar

Kashyap

et al. 2015

Sci Rep

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“…1f ), which is different from the regular K-edge of oxygen in H 2 O and TiO 2 . The same pre-edge of oxygen has been detected in studies of Al(OH) 3 25 , and has been attributed to unpaired O originating from the loss of hydrogen in the hydroxyl layer of Al(OH) 3 26 induced by electron radiolysis. This provides implicit evidence that the surface shell around TiO 2 NPs also contains hydroxyl species due to diffusion of H atoms into the anatase TiO 2 NPs.…”

Section: Resultssupporting

confidence: 66%

Self-hydrogenated shell promoting photocatalytic H2 evolution on anatase TiO2

Yin

Peng³

et al. 2018

Nat Commun

199

159

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As one of the most important photocatalysts, TiO2 has triggered broad interest and intensive studies for decades. Observation of the interfacial reactions between water and TiO2 at microscopic scale can provide key insight into the mechanisms of photocatalytic processes. Currently, experimental methodologies for characterizing photocatalytic reactions of anatase TiO2 are mostly confined to water vapor or single molecule chemistry. Here, we investigate the photocatalytic reaction of anatase TiO2 nanoparticles in water using liquid environmental transmission electron microscopy. A self-hydrogenated shell is observed on the TiO2 surface before the generation of hydrogen bubbles. First-principles calculations suggest that this shell is formed through subsurface diffusion of photo-reduced water protons generated at the aqueous TiO2 interface, which promotes photocatalytic hydrogen evolution by reducing the activation barrier for H2 (H–H bond) formation. Experiments confirm that the self-hydrogenated shell contains reduced titanium ions, and its thickness can increase to several nanometers with increasing UV illuminance.

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“…The peak intensity at 537 eV energy loss represents the main edge feature characteristic of hydrogen bonding in liquid water, confirmed with X-ray Raman spectroscopy (Bergmann et al, 2002). Jiang and Spence (2011) recently observed a pre-edge feature at 528 eV during the damage of oxide materials caused by the removal of hydrogen atoms in Al(OH) 3 . That peak is attributed to a shift in the oxygen 1 s orbital due to an unpaired oxygen atom caused by dehydration from the electron beam (Jiang & Spence, 2011).…”

Section: Electron Probe Induced Radiolysis Damage To Watermentioning

confidence: 99%

Atomic-Scale Imaging and Spectroscopy for In Situ Liquid Scanning Transmission Electron Microscopy

et al. 2012

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Observation of growth, synthesis, dynamics, and electrochemical reactions in the liquid state is an important yet largely unstudied aspect of nanotechnology. The only techniques that can potentially provide the insights necessary to advance our understanding of these mechanisms is simultaneous atomic-scale imaging and quantitative chemical analysis (through spectroscopy) under environmental conditions in the transmission electron microscope. In this study we describe the experimental and technical conditions necessary to obtain electron energy loss (EEL) spectra from a nanoparticle in colloidal suspension using aberration-corrected scanning transmission electron microscopy (STEM) combined with the environmental liquid stage. At a fluid path length below 400 nm, atomic resolution images can be obtained and simultaneous compositional analysis can be achieved. We show that EEL spectroscopy can be used to quantify the total fluid path length around the nanoparticle and demonstrate that characteristic core-loss signals from the suspended nanoparticles can be resolved and analyzed to provide information on the local interfacial chemistry with the surrounding environment. The combined approach using aberration-corrected STEM and EEL spectra with the in situ fluid stage demonstrates a plenary platform for detailed investigations of solution-based catalysis.

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In situ EELS study of dehydration of Al(OH)3 by electron beam irradiation

Cited by 22 publications

References 22 publications

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

Self-hydrogenated shell promoting photocatalytic H2 evolution on anatase TiO2

Atomic-Scale Imaging and Spectroscopy for In Situ Liquid Scanning Transmission Electron Microscopy

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