NiAl-layered Double Hydroxide Research Articles

Cure Index for labeling curing potential of epoxy/LDH nanocomposites: A case study on nitrate anion intercalated Ni-Al-LDH

Curing process of thermoset nanocomposites strongly depends on the nature and functionality of nanoparticles. In the present work, Ni-Al layered double hydroxide (LDH) was synthesized and intercalated with nitrate anion via solvothermal method to form Ni-Al-NO3 LDH and characterized by FTIR, X-ray diffraction (XRD) and TGA techniques. Characterization proved the synthesis of Ni-Al LDH intercalated with nitrate anion by d-spacing value of 0.76 nm. Epoxy nanocomposite containing 0.1 wt.% of the synthesized LDH was prepared and its curing potential was studied by nonisothermal differential scanning calorimetry (DSC). According to the results and qualitative evaluations made by the use of Cure Index (CI), epoxy nanocomposite containing Ni-Al-NO3 LDHs revealed Excellent cure thanks to the participation of nitrate anion in epoxide ring opening reaction. The anions attack to the carbon atom of epoxide rings and breaking down the CO band led to facilitation of the curing reaction and formation of a more condensed cross-linked network. It was recognized that the CI can be used in labeling epoxy/LDH nanocomposites for curing potential demonstration.

Biotemplate-Assisted Synthesis of Layered Double Oxides Confining Ultrafine Ni Nanoparticles as a Stable Catalyst for Phenol Hydrogenation

A confined Ni(0) nanocatalyst derived from NiAl-layered double hydroxide (NiAl-LDH), with ultrafine Ni nanoparticles implanted in the NixAlyO support, was first fabricated by the urea coprecipitation method using pine pollen as a biotemplate, together with subsequent calcination/reduction process. This hollow biotemplate-assisted catalyst displayed high phenol-hydrogenation activity and stability, which can be ascribed to its higher surface area, better dispersibility, and ultrafine Ni particle size. The hollow morphology and confinement effect of lamellar NiAl-LDH can not only lead to better dispersion of the active Ni(0) species, but also strengthen the interaction between Ni(0) species and NixAlyO support. This protocol can overcome the shortcomings of conventional LDH-derived catalysts that lack specifically shaped morphology and hierarchical structure, inhibiting the aggregation of the Ni nanoparticles, hence resulting in its good activity and stability.

Low Carbonate Contaminative and Ultrasmall NiAl LDH Prepared by Acid Salt Treatment with High Adsorption Capacity of Methyl Orange

Layered double hydroxides (LDHs) are attracting intense research interests as methyl orange (MO) adsorbent due to the unique anionic exchange ability. Herein, ultrasmall NiAl LDHs with Cl– intercal...

Ni-Al layered double hydroxides (LDHs) coated superhydrophobic mesh with flower-like hierarchical structure for oil/water separation

Recently, there is an urgent demand to remove oil and organic solvents with low surface tension from oily wastewater, which promotes the application of interface biomimetic materials in oil/water separation. In our work, a novel NiAl LDHs coated superhydrophobic and superoleophilic stainless steel mesh (SS-SSM) with efficient oil/water separation performance was successfully prepared. The 3D flower-like structure intercalated by LDHs monocrystalline flakes was anchored on metallic wires in urea solution by a hydrothermal method and decorated with low surface energy molecules. The as-prepared mesh exhibited perfect superhydrophobicity with water contact angle of 156° and sliding angle of 5°, thus achieving self-cleaning property. In addition, the separation efficiency for a series of oil/water mixtures of the coated mesh was studied, which was up to 98% for most sample oils. More importantly, even treated under severer conditions such as ultrasonic, abrasion and chemical etching solution, the as-prepared meshes possessed good reproducibility in terms of contact angles and separation efficiencies. It is expected that the designed mesh could provide a b brand-new method for superhydrophobic surface coating, making it a potential functional material for self-cleaning, anti-corrosion, fluid drag reduction and oil/water separation.

Pillaring-Effect Induced Ultrahigh-Rate Pseudocapacitive Energy Storage Based on Layered Double Hydroxide Nanoplate Arrays

Two-dimensional layered materials with large interlayer distance to guarantee facilitated electrolyte diffusion are regarded as good candidates for high-performance supercapacitors. In this work, NiAl-layered double hydroxide (LDH) nanoplate arrays with NO3–, pentanesulfonate (PS) and dodecanesulfonate (DS) ions in their interlayer were synthesized, and the effect of different pillaring anions on the electrochemical properties of LDH electrodes was investigated. Combined studies of experiments and theoretical calculations show that the pillaring-effect of long-chain molecules drastically reduces the ion transport resistance between the electrode and electrolyte. An enhanced specific capacitance (1125 F g–1 at 1 A g–1) and a ultrahigh-rate capability (72.8% retention at 200 A g–1) were achieved for the NiAl(DS)-LDH electrode. Such an electrode was further assembled into an all-solid-state supercapacitor, which exhibits a significantly improved energy and power densities as well as long-term stability. This...

An aluminum silicate modified Ni-Al LDHs film to improve the corrosion resistance of AZ31 Mg alloy

Improving the corrosion resistance of Mg alloys is essential for broadening its application. In this paper, the aluminum silicate-modified Ni-Al layered double hydroxides (LDHs) were synthesized by co-precipitation, and then the aluminum silicate-modified Ni-Al LDHs film was fabricated on the surface of AZ31 Mg alloy to improve the anti-corrosion property via a facile in-situ growth method. The results showed that the aluminum silicate modified Ni-Al LDHs film could effectively improve the corrosion resistance of AZ31 Mg alloy and could maintain for a long time. Comparing to that of the bare AZ31 Mg alloy, the corrosion current density of the one with the aluminum silicate modified Ni-Al LDHs film was decreased by 2 orders of magnitude. It was due to the blocking effect of the aluminum silicate modified on the Ni-Al LDHs and the adsorption of Cl− by the LDHs film, delaying the corrosion of the Mg alloys. This work not only broadens the modification method of LDHs but also provides a new strategy for the corrosion protection of Mg alloys.

Controlled Growth of LDH Films with Enhanced Photocatalytic Activity in a Mixed Wastewater Treatment.

Due to multiple charge transport pathways, adjustable layer spacing, compositional flexibility, low manufacturing cost, and absorption of visible light, layered double hydroxides (LDHs) are a promising material for wastewater treatment. In this study, LDH films and Fe-doped LDH films with different metal ions (Ni, Al, Fe) on the surface of conductive cloth were successfully prepared and applied for the photocatalytic degradation of wastewater containing methyl orange and Ag ions under visible-light irradiation. The chemical state of Fe ions and the composition of LDHs on methyl orange photodegradation were investigated. The experimental results showed that LDH films exhibited high photocatalytic activity. The photocatalytic activity of LDH films on methyl orange improved in the mixed wastewater, and the Fe-doped NiAl–LDH films exhibited best visible-light photocatalytic performance. The analysis showed that Ag ions in the mixed wastewater were reduced by the LDH films and subsequently deposited on the surface of the LDH films. The Ag nanoparticles acted as electron traps and promoted the photocatalytic activity of the LDH films on methyl orange. Thus, we have demonstrated that prepared LDH films can be used in the treatment of mixed wastewater and have broad application prospects in environmental remediation and purification processes.

Intercalation of olanzapine into CaAl and NiAl Layered Double Hydroxides for dissolution rate improvement: Synthesis, characterization and in vitro toxicity

The aim of this work was to develop and characterize different Layered Double Hydroxides (LDHs) loaded with of Olanzapine (OLZ), CaAl:OLZ and NiAl:OLZ, by thermogravimetry (TG), differential scanning calorimetry (DSC), Fourier Transform Infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), dissolution rate improvement, inhibition of AAPH-induced hemolysis and toxicity prospections with Artemia salina assay. No peaks of OLZ were found on diffractograms of both systems (5%) indicating amorphization of OLZ. This behavior was decreased with the increasing of drug. FT-IR spectra showed decreasing, displacements, suppressions and enlargements of bands in specific regions suggesting OLZ intercalation in both HDLs. No OLZ endothermic events was found in DSC curves indicating a decrease in the drug crystallinity, excepting for samples with 30% of OLZ. The dissolution profile evidenced that in 45 min CaAl:OLZ 5% and NiAl:OLZ 5% presented the maximum drug solubilization of 89.08 and 61.66%, respectively. In the inhibition of AAPH-induced hemolysis, both systems, showed significant inhibition (p ≤ 0.05) compared to the negative control, and Artemia salina assay evidenced that both HDLs (5%) did not cause the significant death of the specimens compared to OLZ in 24 h. The exposed results reinforced the proposed use of LDHs as functional excipients.

Synthesis of NiAl layered double hydroxides intercalated with aliphatic dibasic anions and their exchange with heptamolybdate

Layered double hydroxides (LDH) of general formula Ni1-x Alx(OH)2(A)x/2. mH2O were obtained by a co-precipitation method at constant pH, using succinate (C4H4O42−), adipate (C6H8O42−) and sebacate (C10H16O42−) as compensation anions and two x values, 0.3 and 0.5. The formation of NiAl LDH was evidenced, although in the Al-richer samples carbon analysis and solid-state 27Al NMR spectroscopy indicated the segregation of a small amount of an aluminum-containing phase. To prepare NiAlMo LDH, the original compensation anions were replaced by heptamolybdate ion using an anion exchange method. The results showed almost complete anion exchange in most samples, with small amounts of residual organic material, evidencing easy removal of the aliphatic dibasic anions as compared with terephthalate. The samples were characterized by FTIR, XRD, ICP-OES, CHN and Raman and 27Al MAS solid-state NMR spectroscopies.

A novel pre-sulfided hydrotreating catalyst derived from thiomolybdate intercalated NiAl LDHs

A pre-sulfided hydrotreating catalyst was prepared via thiomolybdate intercalated NiAl layered double hydroxides (LDHs) followed by calcination under N2. Upon calcination, the decomposition of thiomolybdate in the interlayer produces MoS2 and releases sulfur to react with nickel in the sheets to produce NiSx. Poorly crystallized MoS2 and NiS2 are formed at 300 °C. However, MoS2 is converted into MoO2 while NiS2 is transformed into NiS and Ni3S2 at higher temperatures. The coordinatively unsaturated sites (CUS) on catalysts and dibenzothiophene (DBT) hydrodesulfurization (HDS) activity decrease as the calcination temperature increases. The catalyst calcined at 300 °C exhibits a little higher HDS activity but 2.3 times higher activity in tetralin (THN) hydrogenation than an oxidic catalyst derived from a molybdate intercalated LDH. Moreover, it shows 2.2 times higher THN hydrogenation activity than a commercial catalyst containing more metals. This could be ascribed to the formation of CUS and non-stoichiometric sulfur species.

Free-standing cotton-derived carbon microfiber@nickel-aluminum layered double hydroxides composite and its excellent capacitive performance

The main bottleneck of supercapacitor is its low energy density, mainly arising from the low capacity of the electrode materials. Although some pseudocapacitive metal oxide/hydroxides have been selected to improve the energy density of supercapacitor, their low conductivity and inferior reversibility still need to be considered. In this work, we prepared a free-standing composite comprised of NiAl-layered double hydroxide (LDH) nanoflakes decorated on a cotton derived carbon microfiber (CMF@NiAl-LDH) via a facile hydrothermal method. The large-scale and compressible cotton derived carbon fiber with connected three-dimensional pores served as conductive backbones for the growth of the NiAl-LDH nanoflakes. It can not only improve the conductivity of NiAl-LDH, but also amend the distribution of NiAl-LDH nanosheets, leading to both rapid electron and electrolyte ions transport kinetics. The abundant space among NiAl-LDH nanoflakes as well as developed 3D pores of CMF can accommodate the volume expansion of NiAl-LDH during long lifespan cycling. Benefited from these rational design, the as-prepared CMF@NiAl-LDH electrode exhibited significantly improved capacitive performance in terms of high specific capacitance (1667 F g−1 at 1 A g−1), excellent rate performance (68.7% retained at 15 A g−1) and remarkable cyclic stability (105.4% maintained after 2000 cycles) in aqueous electrolytes. The assembled CMF@NiAl-LDH//porous carbon asymmetric supercapacitor can deliver a large energy density of 45.2 Wh Kg−1. This investigation suggests that the prepared CMF@NiAl-LDH electrode offers a great potential in large-scale energy storage device applications.

Confined PtNi catalysts for enhanced catalytic performances in one-pot cellobiose conversion to hexitols: a combined experimental and DFT study

Ni nanoclusters were confined inside an alumina matrix through Ni–Al layered double hydroxide (NiAl-LDH) decomposition methods and showed great performance in one-pot cellobiose conversion to hexitols.

Electricity generation from a Ni-Al layered double hydroxide-based flexible generator driven by natural water evaporation

Natural water evaporation (NWE) is spontaneous and ubiquitous process that absorbs ambient thermal energy. Scavenging ambient thermal energy into electricity by NWE provides a promising approach to supply power for self-powered and low-cost devices and systems. Suitable materials and techniques are required to use this ubiquitous natural process for electricity generation. Herein, a continuous NWE-driven flexible generator is fabricated by painting Ni-Al layered double hydroxide (LDH) on a polyethylene terephthalate substrate at room temperature. The generator operates through an NWE-driven gradient of water that flows across the naturally formed surface-charged nanochannels between Ni-Al LDH flakes; i.e., the streaming potential mechanism. The output electrical characteristics of the device can be controlled by adjusting the environmental moisture and wind velocity. Continuous electricity output with a comparatively high power density of 16.1 μW cm−3 is achieved from a generator. The generator can maintain a stable output power under deformation. The output power of the generator can be scaled up to continuously power integrated circuit devices such as a digital calculator. Given the easy fabrication process of this flexible NWE-driven generator using an environmentally friendly LDH and its continuous electricity output with relatively high power density, this generator represents an important step towards practical green ambient energy harvesting.

Structural evolution of NiAl-based layered nanostructures grown by a low-temperature hydrothermal method

We report on the growth mechanism of NiAl-based layered nanostructures on rigid substrates using a low-temperature hydrothermal method. NiAl-layered double hydroxide (LDH) structures were grown with various source concentrations and growth times. Structural and optical investigations showed that uniform NiAl-LDHs were grown on the substrates because Al(OH)3 was sufficiently supplied from the aluminum thin film seed layer when the Ni source concentration was low and in the initial stage of the growth. However, a bilayer of NiAl-LDH and α-Ni(OH)2 was formed when the Ni sources were sufficiently supplied and the growth time was long enough because of the deficient Al(OH)3 sources at the growth front.

Sensitive electrochemical detection of methyl parathion in the presence of para-nitrophenol on a glassy carbon electrode modified by a functionalized NiAl-layered double hydroxide

An inorganic–organic composite material was prepared by the insertion of bis(ethylhexyl)hydrogen phosphate (BEHP) within the interlayer space of a nickel-aluminum–layered double hydroxide (NiAl LDH). X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared were used to characterize the pristine and modified LDH (NiAl–BEHP), which together confirm the intercalation of BEHP in the mineral structure. Cyclic voltammetry using [Fe(CN) 6 ] 3− as an anionic redox probe demonstrated a significant decrease in the anion exchange capacity of NiAl upon modification. Used as electrode modifier for methyl parathion (MP) detection, a remarkable increase in MP signal on NiAlBEHP–modified glassy carbon electrode (GCE/NiAl–BEHP) was observed, because of the high hydrophobicity character of the modified LDH. The signal assigned to the electroactivity of the nitro group being less stable than that of the reduction of the nitroso group, the use of both functions was explored for the calibration experiments. Sensitivities of 0.79 μA μM −1 and 0.14 μA μM −1 were obtained, with detection limits of 2.28 × 10 −8 and 12.4 × 10 −8 mol L −1 for nitro and nitroso groups, respectively. However, the linearity range was more important for the nitroso group (0.5–12 μM) as compared to the nitro group (0.5–3.5 μM). Moreover, the signal of the nitroso group showed poor interference with some chemical species likely to be encountered in the presence of MP. The GCE/NiAl-BEHP–modified electrode was particularly effective for the differentiation of 4-nitrophenol (4-NP) from MP. Interestingly, the decrease in the sensor sensitivity was negligible (0.13 μA μM −1 ) when the calibration curve of MP was plotted in the presence of 1 μM of 4-NP. The poor efficiency of the sensor to quantify 4-NP was probably because of the high organophilic character of the electrode material. The developed method was successfully applied to quantify MP in spring water. Un matériau composite inorgano–organique a été préparé par insertion d'hydrogénophosphate de bis(éthylhexyl) (BEHP) dans l'espace intercouche d'un hydroxyde double lamellaire (HDL) nickel–aluminum (NiAl). La diffraction de rayons X, l'analyse thermique et la spectroscopie infrarouge ont été utilisées pour caractériser l’HDL de départ et celui issue de l'intercalation (NiAl–BEHP), techniques qui toutes ont confirmé le processus d'insertion de la molécule organique dans la structure minérale. La voltammétrie cyclique utilisant la sonde électrochimique anionique [Fe(CN) 6 ] 3− a montré une diminution significative de la capacité d'échange anionique de l’HDL lors de la modification. Utilisé comme modifiant d'électrode pour la détection du méthyl parathion (MP), une augmentation remarquable du signal MP sur l'électrode de carbone vitreux (CV) modifiée par NiAl−BEHP (CV/NiAl–BEHP) a été observée en raison du caractère hautement hydrophobe dudit matériau. Le signal attribué à l'électroactivité du groupe nitro étant moins stable que celui de la réduction du groupe nitroso, l'utilisation des deux fonctions a été explorée pour les expériences de calibration. Des sensibilités de 0,79 μA μM −1 et 0,14 μA μM −1 ont été obtenues, avec des limites de détection de 2,28 × 10 −8 et 12,4 × 10 −8 mol L −1 , respectivement pour les groupements nitro et nitroso. Cependant, la gamme de linéarité la plus importante a été celle présentée par le groupement nitroso (0,5 μM à 12 μM) par rapport au groupe nitro (0,5 μM à 3,5 μM). De plus, le signal du groupe nitroso a montré une faible interférence avec certaines espèces chimiques susceptibles d'interférer avec le MP. L'électrode modifiée CV/NiAl−BEHP a été particulièrement sélective vis-à-vis des deux analytes étudiés. Ce qui est plus intéressant, la diminution de la sensibilité du capteur a été négligeable (0,13 μA μM −1 ) lorsque la courbe d'étalonnage du MP a été tracée en présence de 1 μM de 4-NP. Cette observation peut être attribuée au caractère organophile élevé du matériau NiAl−BEHP déposé sur l’électrode de carbone vitreux. La méthode développée a été appliquée avec succès pour quantifier le MP dans une eau de source.

Assembly of Ni–Al layered double hydroxide and oxide graphene quantum dots for supercapacitors

Abstract

Synthesis and Electrochemical Properties of CoAl, NiAl, CoFe and NiFe Layered Double Hydroxide Films

Synthesis and Electrochemical Properties of CoAl, NiAl, CoFe and NiFe Layered Double Hydroxide Films

Fabrication of Ni-Al LDH/nitramine-N-doped graphene hybrid composites via a novel self-assembly process for hybrid supercapacitors

The ingenious synthesis strategies have been highly desired to construct hybrid composites with intriguing properties for supercapacitors. Herein, Ni-Al LDH (layered double hydroxide)/NNDG (nitramine-N-doped graphene) hybrid composites with a layered structure were fabricated via a novel self-assembly process. Nitramine-N dopants anchored to graphene framework allow the self-immobilization of delaminated Ni-Al LDH nanolayers onto the surface of two-dimensional carbonaceous scaffolds and boost the abundance of Ni3+ within hybrid composites along with the removal of interlayer anions within Ni-Al LDH-NO3. Remarkably, the combination of Ni-Al LDH with NNDG can not only enhance the utilization of electrochemically active matrixes in dependence on the increase of electrolyte accessible active sites, but also maximize the electrochemically active contact between inorganic macromolecules and carbonaceous matrixes in favor of the establishment of conductive architectures. Furthermore, Ni-Al LDH/NNDG hybrid composites achieve a specific capacity of 975 C g−1 at a specific current of 1.0 A g−1 with a capacity retention of 75% as the increase of specific currents to 10 A g−1, superior to Ni-Al LDH-NO3 and Ni-Al LDH/rGO hybrid composites. The hybrid supercapacitor comprised of Ni-Al LDH/NNDG hybrid composites as a positive electrode and activated carbon as a negative electrode attains a high energy density of 59 Wh kg−1 with a power density of 1991 W kg−1 at a specific current of 2.5 A g−1 and retains 95% of the initial capacitance after 10 000 cycles at a specific current of 10 A g−1. The excellence electrochemical performance demonstrates clearly the potential application of self-assembled Ni-Al LDH/NNDG hybrid composites for hybrid supercapacitors.

Synthesis, characterization and enhanced visible light photocatalytic activity of Bi2WO6/Ni–Al layered double hydroxide composites

Bi2WO6/Ni–Al layered double hydroxide (LDH) composites assembled from Bi2WO6 and Ni–Al LDH composites were prepared by a simple hydrothermal method. The as-prepared composites were characterized by XRD, SEM, FT-IR, UV–Vis DRS, XPS, and N2 adsorption–desorption techniques. The results showed that the Bi2WO6/Ni–Al LDH composites heterojunction exhibited greatly increased specific surface area, improved the visible light absorption, and promoted the electron–hole pairs generated and separation efficient. Furthermore, the photocatalytic performance of Bi2WO6/Ni–Al LDH composites toward degradation of rhodamine B, safranine T, and tetracycline tightly depended on the mass fraction of LDH. At the LDH weight loading of 5 wt%, the photocatalytic degradation efficiency of Bi2WO6/Ni–Al LDH-5 composites reached 83.98, 99.74, and 84.51% within 8.0, 4.0, and 11.0 h, respectively. The enhanced activity of Bi2WO6/Ni–Al LDH-5 composites may be attributed to the concerted photocatalysts effect between two constituents of as-prepared composites. A possible photocatalytic mechanism was proposed according to various performance characterization and experimental results. In addition, the as-prepared catalysts showed remarkable reusability and stability in four successive cycles. It is wished that the Bi2WO6/Ni–Al LDH composites could be used as photocatalysts for energy transformation and environmental treatment. This material provides new ideals for degradation of organic compounds pollutants.

NiAl Layered Double Hydroxides and PdNiO as Multifunctional Anodes for Prospective Self‐Powered Lab‐on‐a‐Chip Dopamine Sensors

AbstractThe purpose of this work is the evaluation of two bimetallic materials, PdNiO and NiAl‐layered double hydroxides (NiAl‐LDHs) for their prospective use in Lab‐on‐a‐Chip devices, in which urea contained in human urine is used as fuel to provide the energy required by the device and dopamine in the sample is detected. A urea microfluidic fuel cell, using human urine as fuel and NiAl‐LDHs and PdNiO as anodes, was constructed and evaluated, resulting in a cell potential of 1 V with 50.19 mW/cm2 power density for NiAl‐LDHs and 0.9 V and 32.94 mW/cm2 for PdNiO. The multifunctionality of these anodes was extended for detecting dopamine with detection limits of 7.38×10−8 M and 5.46×10−6 M for NiAl‐LDHs and PdNiO, respectively. The higher content of hydroxides on NiAl‐LDHs than PdNiO material allowed a better activity for urea oxidation and dopamine detection. These results show the prospects for self‐powered biomedical Lab‐on‐a‐Chip device development.