Structural Characterisation of Complex Layered Double Hydroxides and TGA-GC-MS Study on Thermal Response and Carbonate Contamination in Nitrate- and Organic-Exchanged Hydrotalcites

2015 ◽  
Vol 21 (42) ◽  
pp. 14975-14986 ◽  
Author(s):  
Eleonora Conterosito ◽  
Luca Palin ◽  
Diego Antonioli ◽  
Davide Viterbo ◽  
Enrico Mugnaioli ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Thermal Response ◽  
Structural Characterisation ◽  
Double Hydroxides

scholarly journals Order and Disorder in Layered Double Hydroxides: Lessons Learned from the Green Rust Sulphate - Nikischerite Series.

2020 ◽  
Author(s):  
Knud Dideriksen ◽  
Laura Voigt ◽  
Marco Mangayayam ◽  
Simon H. J. Eiby ◽  
Case M. van Genuchten ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Coherent Scattering ◽  
Lessons Learned ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Structural Characterisation ◽  
Al Content ◽  
Contaminant Remediation ◽  
Structural Coherence ◽  
Double Hydroxides

<div>Layered double hydroxides (LDHs) occur naturally and are synthesised for catalysis, drug</div><div>delivery and contaminant remediation. They consist of Me(II)-Me(III) hydroxide sheets</div><div>separated by hydrated interlayers and weakly held anions. Often, LDHs are nanocrystalline and</div><div>sheet stacking and Me(II)-Me(III) arrangement can be disordered, which influence reactivity and</div><div>complicate structural characterisation. We have used pair distribution function (PDF) analysis, to</div><div>provide detailed information about local and medium range order (< 9 nm), to determine the</div><div>structure of synthetic Fe(II)-Fe(III)/Al(III) LDH. The data are consistent with ordered Me(II)</div><div>and Me(III) in hydroxide sheets, where structural coherence along the c axis decreases with </div><div>increasing Al content. The PDF for Fe(II)-Al(III) LDH (nikischerite) is best matched by a</div><div>pattern for a single metal hydroxide sheet. Parallel to decreased structural coherence between</div><div>layers, coherence within layers decreased to ~6 nm for synthetic nikischerite. Thus, disorder</div><div>developed within and between the sheets, resulting in mosaic crystals with coherent scattering</div><div>domains decreasing in all directions. The high density of grain boundary terminations would</div><div>affect reactivity. Based on classical nucleation theory and the Kossel crystal growth model, we</div><div>propose that loss of structural coherence stems from increased supersaturation and the presence</div><div>of Al-hydroxides during formation of the Al-rich LDH</div>

scholarly journals Order and Disorder in Layered Double Hydroxides: Lessons Learned from the Green Rust Sulphate - Nikischerite Series.

2020 ◽  
Author(s):  
Knud Dideriksen ◽  
Laura Voigt ◽  
Marco Mangayayam ◽  
Simon H. J. Eiby ◽  
Case M. van Genuchten ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Coherent Scattering ◽  
Lessons Learned ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Structural Characterisation ◽  
Al Content ◽  
Contaminant Remediation ◽  
Structural Coherence ◽  
Double Hydroxides

<div>Layered double hydroxides (LDHs) occur naturally and are synthesised for catalysis, drug</div><div>delivery and contaminant remediation. They consist of Me(II)-Me(III) hydroxide sheets</div><div>separated by hydrated interlayers and weakly held anions. Often, LDHs are nanocrystalline and</div><div>sheet stacking and Me(II)-Me(III) arrangement can be disordered, which influence reactivity and</div><div>complicate structural characterisation. We have used pair distribution function (PDF) analysis, to</div><div>provide detailed information about local and medium range order (< 9 nm), to determine the</div><div>structure of synthetic Fe(II)-Fe(III)/Al(III) LDH. The data are consistent with ordered Me(II)</div><div>and Me(III) in hydroxide sheets, where structural coherence along the c axis decreases with </div><div>increasing Al content. The PDF for Fe(II)-Al(III) LDH (nikischerite) is best matched by a</div><div>pattern for a single metal hydroxide sheet. Parallel to decreased structural coherence between</div><div>layers, coherence within layers decreased to ~6 nm for synthetic nikischerite. Thus, disorder</div><div>developed within and between the sheets, resulting in mosaic crystals with coherent scattering</div><div>domains decreasing in all directions. The high density of grain boundary terminations would</div><div>affect reactivity. Based on classical nucleation theory and the Kossel crystal growth model, we</div><div>propose that loss of structural coherence stems from increased supersaturation and the presence</div><div>of Al-hydroxides during formation of the Al-rich LDH</div>

Acceptorless amine dehydrogenation and transamination using Pd-doped layered double hydroxides

2018 ◽  
Author(s):  
Diana Ainembabazi ◽  
Nan An ◽  
Jinesh Manayil ◽  
Kare Wilson ◽  
Adam Lee ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Oxidation States ◽  
Secondary Amines ◽  
Primary Amines ◽  
Acid Dissolution ◽  
Oxidative Amination ◽  
Strong Function ◽  
Excellent Activity ◽  
High Yields ◽  
Double Hydroxides

<div> <p>The synthesis, characterization, and activity of Pd-doped layered double hydroxides (Pd-LDHs) for for acceptorless amine dehydrogenation is reported. These multifunctional catalysts comprise Brønsted basic and Lewis acidic surface sites that stabilize Pd species in 0, 2+, and 4+ oxidation states. Pd speciation and corresponding cataytic performance is a strong function of metal loading. Excellent activity is observed for the oxidative transamination of primary amines and acceptorless dehydrogenation of secondary amines to secondary imines using a low Pd loading (0.5 mol%), without the need for oxidants. N-heterocycles, such as indoline, 1,2,3,4-tetrahydroquinoline, and piperidine, are dehydrogenated to the corresponding aromatics with high yields. The relative yields of secondary imines are proportional to the calculated free energy of reaction, while yields for oxidative amination correlate with the electrophilicity of primary imine intermediates. Reversible amine dehydrogenation and imine hydrogenation determine the relative imine:amine selectivity. Poisoning tests evidence that Pd-LDHs operate heterogeneously, with negligible metal leaching; catalysts can be regenerated by acid dissolution and re-precipitation.</p> </div> <br>

Antibiotic-anionic Clay Matrix Used for Drug Controlled Release

2018 ◽  
Vol 69 (2) ◽  
pp. 321-323
Author(s):  
Georgeta Zegan ◽  
Elena Mihaela Carausu ◽  
Loredana Golovcencu ◽  
Alina Sodor Botezatu ◽  
Eduard Radu Cernei ◽  
...  
Keyword(s):  
Controlled Release ◽  
Layered Double Hydroxides ◽  
Bioactive Molecules ◽  
Drug Controlled Release ◽  
Anionic Clays ◽  
Anionic Clay ◽  
Toxicological Studies ◽  
High Efficient ◽  
Clay Matrix ◽  
Double Hydroxides

Anionic clay matrix acting as drug controlled release system have shown in last years a great potential for delivery of bioactive molecules and chemical therapeutics. This organic-inorganic nanohybrid system is high efficient offering an excellent protection of intercalated compounds from degradation. Compared to other nanoparticles used in medical area, anionic clays type layered double hydroxides have found to be biocompatible according to toxicological studies. Ampicillin containing MgAlLDHs and ZnAlLDH samples have been prepared following two routes: anion-exchange procedure and reconstruction from calcined layered double hydroxides. Solid samples have been characterized by FTIR and SEM-EDX highlighting the alteration of pristine LDHs structure when the antibiotic is introduced in the interlayer gallery.

Nanohybrid Enzymes - Layered Double Hydroxides: Potential Applications

2006 ◽  
Vol 2 (3) ◽  
pp. 283-294 ◽  
Author(s):  
Claude Forano ◽  
Stephanie Vial ◽  
Christine Mousty
Keyword(s):  
Layered Double Hydroxides ◽  
Potential Applications ◽  
Double Hydroxides
Sign in / Sign up

Export Citation Format

Share Document