scholarly journals Preparation of Layered Double Hydroxides toward Precisely Designed Hierarchical Organization

2019 ◽  
Vol 3 (3) ◽  
pp. 68 ◽  
Author(s):  
Rattanawadee (Ploy) Wijitwongwan ◽  
Soontaree (Grace) Intasa-ard ◽  
Makoto Ogawa
Keyword(s):  
Layered Double Hydroxides ◽  
Drug Carrier ◽  
Particle Morphology ◽  
Hierarchical Organization ◽  
Synthetic Methods ◽  
Practical Application ◽  
Preparation Methods ◽  
Wide Range ◽  
Varied Composition ◽  
Double Hydroxides

Layered double hydroxides (LDHs) are a class of materials with useful properties associated with their anion exchange abilities for a wide range of materials’ applications including adsorbent, catalyst and its support, ceramic precursor, and drug carrier. In order to satisfy the requirements for the detailed characterization and the practical application, the preparation of LDHs with varied composition and particle morphology has been examined extensively. The versatility of the preparation methods led LDHs with varied composition and micro/macroscopic morphology, which makes the application of LDHs more realistic. In the present review article, synthetic methods of LDHs are overviewed in order to highlight the present status of the LDHs for practical application.

scholarly journals Research Progress of NiMn Layered Double Hydroxides for Supercapacitors: A Review

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 747 ◽  
Author(s):  
Ai-Lan Yan ◽  
Xin-Chang Wang ◽  
Ji-Peng Cheng
Keyword(s):  
Layered Double Hydroxides ◽  
Electrode Materials ◽  
Low Cost ◽  
Specific Capacity ◽  
Research Progress ◽  
Electrochemical Performances ◽  
Preparation Methods ◽  
Large Power ◽  
Supercapacitor Application ◽  
Double Hydroxides

The research on supercapacitors has been attractive due to their large power density, fast charge/discharge speed and long lifespan. The electrode materials for supercapacitors are thus intensively investigated to improve the electrochemical performances. Various transition metal layered double hydroxides (LDHs) with a hydrotalcite-like structure have been developed to be promising electrode materials. Earth-abundant metal hydroxides are very suitable electrode materials due to the low cost and high specific capacity. This is a review paper on NiMn LDHs for supercapacitor application. We focus particularly on the recent published papers using NiMn LDHs as electrode materials for supercapacitors. The preparation methods for NiMn LDHs are introduced first. Then, the structural design and chemical modification of NiMn LDH materials, as well as the composites and films derived from NiMn LDHs are discussed. These approaches are proven to be effective to enhance the performance of supercapacitor. Finally, the reports related to NiMn LDH-based asymmetric supercapacitors are summarized. A brief discussion of the future development of NiMn LDHs is also provided.

scholarly journals Efficient Exfoliation of Layered Double Hydroxides; Effect of Cationic Ratio, Hydration State, Anions and Their Orientations

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 346 ◽  
Author(s):  
Jayakumar Karthikeyan ◽  
Helmer Fjellvåg ◽  
Silje Bundli ◽  
Anja Olafsen Sjåstad
Keyword(s):  
Layered Double Hydroxides ◽  
Particle Morphology ◽  
Clear Correlation ◽  
Water Molecules ◽  
Nitrate Anion ◽  
Hydration State ◽  
Double Hydroxides ◽  
Charge Balancing ◽  
Nitrate Anions ◽  
Anion Type

The exfoliation ability of nitrate based Mg1−xAlx(OH)2(NO3)x·mH2O layered double hydroxides (Mg-Al LDH) in formamide into single or multilayer nanosheets depends strongly on nitrate anion orientation and layer charge. Our systematic studies used materials that were likely to disclose differences with respect to anion type and their concentrations in the interlayer gallery. We assured to avoid any carbonate incorporation into the galleries for nitrate, chloride, iodide, and sulfate based Mg-Al LDHs. Furthermore, the comparative exfoliation experiments were conducted for fully hydrated samples with as similar particle morphology as possible. The exfoliation of nitrate Mg-Al LDH is far superior to similar clays with carbonate, sulfate, chloride, or iodide as charge balancing anions. Quantitative analysis of exfoliation yield for pre-treated, fully hydrated samples, shows an optimum composition for exfoliation into single nanosheets of around x ≈ 0.25, while double or triple layered sheets are encountered for other x-values. We observe a clear correlation between the expansion of the interlayer gallery due to progressing tilts of nitrate anions and water molecules out of the horizontal interlayer plane, suspension turbidity, and degree of exfoliation. The established correlations extends to nitrate Ni-Al LDH materials. We finally claim that morphology is a dominating parameter, with house-of-card morphology particles exfoliation far less than platelet-like particles. Hence, hydrothermal treatment may be favorable to enhance exfoliation yields.

Layered Double Hydroxides Applications in the High-Performance Magnetic Nanomaterials

2020 ◽  
Vol 19 (05) ◽  
pp. 1950039
Author(s):  
Abdullah Ahmed Ali Ahmed
Keyword(s):  
Data Storage ◽  
Layered Double Hydroxides ◽  
Environmental Remediation ◽  
High Performance ◽  
Magnetic Nanostructures ◽  
Chemical Properties ◽  
Magnetic Nanomaterials ◽  
High Dispersion ◽  
Wide Range ◽  
Double Hydroxides

Layered double hydroxides (LDHs), which is related to magnetic nanomaterials’ have promising applications due to their unique structural and chemical properties. The easy tunability of cationic metals without changing the LDH structure as well as anion exchange features of LDH interlayer make them potential applications in supercapacitors, batteries, catalysis, water splitting, etc. Moreover, due to the high dispersion of active compounds in the matrix of LDH layers, LDHs have been used to construct various nanostructures such as nanoparticles, 2D monolayer nanosheets and 3D hierarchical’ which are valued in wide nanotechnological applications. Magnetic nanomaterials are an important research area because they have been applied to a wide range of disciplines such as biotechnology, data storage, magnetic fluids, magnetic resonance imaging, environmental remediation and catalysis. LDHs as starting materials including Ni, Fe or/and Co, can be used as magnetic nanomaterials. The combination between LDHs and magnetic nanostructures has improved the magnetic properties of those materials, hence can be used in more applications.

scholarly journals Layered Double Hydroxides as Bifunctional Catalysts for the Aryl Borylation under Ligand-Free Conditions

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 302 ◽  
Author(s):  
Lorenna Silva ◽  
Vinícius Neves ◽  
Vitor Ramos ◽  
Raphael Silva ◽  
José Campos ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Catalytic Efficiency ◽  
X Ray Diffraction ◽  
Wide Range ◽  
Boronic Esters ◽  
Ligand Free ◽  
Double Hydroxides ◽  
Pure Cu ◽  
Derivatives Of ◽  
Health Applications

Organic derivatives of boron, such as boronic esters and acids, are important precursors for a wide range of environmental, energy, and health applications. Several catalytic methods for their synthesis have been reported, even though with the use of toxic and structurally complex ligands. Herein, we demonstrate preliminary studies envisaging the synthesis of boronic esters from an inexpensive catalytic system based on Cu/Al layered double hydroxides (LDH) in the presence of Na2PdCl4. The Cu/ Al LDHs were prepared according to coprecipitation method and characterized by X-ray diffraction (XRD) (with Rietveld refinement) to evaluate the contamination with malachite and other phases. Preliminary catalytic results suggest that pure Cu/Al LDH has potential for the borylation of aryl iodides/ bromides in the absence of base. Indeed, a synergic effect between copper and palladium is possibly related to the catalytic efficiency.

scholarly journals Synthesis and Characterization of Layered Double Hydroxides as Materials for Electrocatalytic Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 725
Author(s):  
Domenica Tonelli ◽  
Isacco Gualandi ◽  
Elisa Musella ◽  
Erika Scavetta
Keyword(s):  
Layered Double Hydroxides ◽  
Metal Centers ◽  
Anionic Clays ◽  
Direct Modification ◽  
Reversible Redox ◽  
Wide Range ◽  
Charge Transfer Reactions ◽  
Double Hydroxides

Layered double hydroxides (LDHs) are anionic clays which have found applications in a wide range of fields, including electrochemistry. In such a case, to display good performances they should possess electrical conductivity which can be ensured by the presence of metals able to give reversible redox reactions in a proper potential window. The metal centers can act as redox mediators to catalyze reactions for which the required overpotential is too high, and this is a key aspect for the development of processes and devices where the control of charge transfer reactions plays an important role. In order to act as redox mediator, a material can be present in solution or supported on a conductive support. The most commonly used methods to synthesize LDHs, referring both to bulk synthesis and in situ growth methods, which allow for the direct modification of conductive supports, are here summarized. In addition, the most widely used techniques to characterize the LDHs structure and morphology are also reported, since their electrochemical performance is strictly related to these features. Finally, some electrocatalytic applications of LDHs, when synthesized as nanomaterials, are discussed considering those related to sensing, oxygen evolution reaction, and other energy issues.

scholarly journals Hydrotalcites in Construction Materials

2020 ◽  
Vol 10 (22) ◽  
pp. 7989
Author(s):  
Anna-Marie Lauermannová ◽  
Iva Paterová ◽  
Jan Patera ◽  
Kryštof Skrbek ◽  
Ondřej Jankovský ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Radioactive Waste ◽  
Construction Industry ◽  
Layered Double Hydroxides ◽  
Building Materials ◽  
Construction Materials ◽  
Water Molecules ◽  
Wide Range ◽  
Waste Repository ◽  
Double Hydroxides

Hydrotalcites are layered double hydroxides displaying a variety of stoichiometry caused by the different arrangement of the stacking of the layers, ordering of the metal cations, as well as the arrangement of anions and water molecules, in the interlayer galleries. The compounds of the hydrotalcite group show a wide range of the possible applications due to their specific properties, such as their large surface area, ion exchange ability, the insolubility in water and most of the organic sorbents, and others. Affordability, wide possibilities of manufacturing, and presence of sufficient natural deposits make hydrotalcites potentially very useful for the construction industry, as either a building material itself or an additive in mortars, concrete or in polymers composites used in constructions. Similar possible application of such material is in leakage control in a radioactive waste repository. The effect of use of these materials for ion exchange, anti-corrosion protection, radioactive ions containment, and similar purposes in building materials is examined in this review.

scholarly journals Layered Double Hydroxide Protective Films Developed on Aluminum and Aluminum Alloys: Synthetic Methods and Anti-Corrosion Mechanisms

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 428 ◽  
Author(s):  
Muhammad Ahsan Iqbal ◽  
Luyi Sun ◽  
Allyson T. Barrett ◽  
Michele Fedel
Keyword(s):  
Aluminum Alloys ◽  
Synthetic Methods ◽  
Self Healing ◽  
Structural Variations ◽  
Protection Mechanism ◽  
Wide Range ◽  
Protective Films ◽  
Corrosion Mechanisms ◽  
Double Hydroxide ◽  
Double Hydroxides

This work reviews the characteristics of layered double hydroxides (LDHs) in the context of protective thin films to enhance the corrosion resistance properties of aluminum alloys. A discussion is made in detail about the LDH protection mechanism and the effect of synthesis approaches on LDH structural variations and the corresponding anti-corrosion behavior. LDHs anion-exchange behavior to host inorganic/organic anions makes them a potential material to investigate for anti-corrosion film. This unique advantage and the availability of a wide range of metal oxide-based layers, interlayer anions, and self-healing properties make LDH family an attractive choice for the development of compact LDHs based smart coating systems.

Layered double hydroxides as the next generation inorganic anion exchangers: Synthetic methods versus applicability

2017 ◽  
Vol 245 ◽  
pp. 62-80 ◽  
Author(s):  
Natalia Chubar ◽  
Robert Gilmour ◽  
Vasyl Gerda ◽  
Matej Mičušík ◽  
Maria Omastova ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Synthetic Methods ◽  
Next Generation ◽  
Inorganic Anion ◽  
Anion Exchangers ◽  
Double Hydroxides
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