NiAl-layered Double Hydroxide Research Articles

Fluoride rechargeable layered double hydroxide powders for dental applications

It has been widely reported that the prevention of early-stage carious lesions requires a sustained therapeutic low-level release of fluoride in the oral cavity. However dental caries remains as one of the most prevalent diseases worldwide. Therefore, there is a requirement for the development of a material capable of releasing fluoride at a therapeutic level. Layered double hydroxides (LDH) have the potential to achieve this by taking up and releasing fluoride repeatedly, such as recharging using a fluoride toothpaste/mouthwash. A range of fluoride rechargeable LDH powders; ZnAl, MgAl (1:1, 2:1 and 3:1) and CaAl (1:1 and 2:1) were successfully synthesised at different ratios and characterised (pXRD, FTIR, SEM and F− ISEs). NiAl LDH did not form an LDH structure at all ratios. The fluoride uptake (from sodium fluoride, NaF) and release (de-ionised water, DW) over two cycles (24 h) from these powders, demonstrated an increase in the LDH lattice interlamellar space and an increase in fluoride uptake in the following order of formulations; CaAl>MgAl>ZnAl LDH. 2:1 MgAl demonstrated the greatest fluoride release with the same amount released during release and re-release. Therefore, LDH has the potential to be incorporated into various applications, while altering the composition or ratio to obtain a desired fluoride uptake or release.

Synthesis, Characterization, and Hydrotreating Activity of NiW Presulfurized Catalysts Prepared via a Tetrathiotungstate-Intercalated NiAl LDH.

A tetrathiotungstate-intercalated NiAl layered double hydroxide (LDH) was synthesized and then calcined under N2 at various temperatures to prepare a series of NiW presulfurized hydrotreating catalysts. Upon calcination, WS42– in the interlayer decomposes into WS3 and then WS2, releasing sulfur to sulfurize nickel in the sheets. The property and activities of catalysts for hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of tetralin are dependent on the calcination temperature. At 300 °C, WS3 can be well maintained, offering highly active hydrogenation sites S22– and superior HDA activity. As the temperature increases up to 500 °C, WS3 converts into WS2, while nickel sulfides migrate to the edge of WS2 to form NiWS phases with high HDS activity. LDH-based presulfurized catalysts can achieve fully sulfurized and well-dispersed tungsten species even at high tungsten loadings and can retain more WS3 even at high temperatures because of the peculiar properties of LDHs. Therefore, they show better HDS and superior HDA activities over an oxidic NiW LDH-based catalyst (LDO) and an alumina-supported NiWS presulfurized catalyst (NiWS/Al2O3). The optimized catalyst shows 1.59 and 1.05 times higher HDS activity than LDO and NiWS/Al2O3 while 2.05 and 1.77 times higher HDA activity than LDO and NiWS/Al2O3, respectively. It also shows better HDS and HDA activity for a real diesel than a NiCoMoW/Al2O3 commercial catalyst.

Study on Simultaneous Removal of Dye and Heavy Metal Ions by NiAl-Layered Double Hydroxide Films.

Herein, nickel-aluminum-layered double hydroxide (NiAl-LDH) films were prepared by the hydrothermal method. Based on the photoinduced reduction ability and degradation of LDHs on heavy metal ions and organic compounds, NiAl-LDH films displayed favorable simultaneous removal performance. Benefiting from the electron traps of heavy metals reduced from solution, the coexisting metal ions improved the photocatalytic activity of NiAl-LDH films on methyl orange. The higher the Fermi level of coexisting metal ion was, the higher the photocatalytic degradation rate of methyl orange obtained. Meanwhile, the removal rates of heavy metal ions (Ag+, Pb2+, and Cu2+) from wastewater were both enhanced and could reach 95%. NiAl-LDH films showed affinity toward Ag+. Furthermore, NiAl-LDH films are tightly coupled with the substrate, providing active sites and a simple method for the catalyst recovery. This study provides new insights into the simultaneous removal of heavy metal ions and organic pollutants using LDH films.

Synthesis of a Crystalline and Transparent Aerogel Composed of Ni–Al Layered Double Hydroxide Nanoparticles through Crystallization from Amorphous Hydrogel

Enormous efforts have been devoted to the development of crystalline aerogels toward heterogeneous catalysis, energy storage, ion/molecular absorption, and luminescence. However, properties of aerogels are not fully exploited due to their low content of functional moieties embedded in their solid networks, low crystallinity, and limited chemical compositions. Herein, we develop a one-pot approach based on crystallization from amorphous metal hydroxides modified with a β-diketone ligand, toward crystalline transition-metal hydroxide aerogels. Synthesis of monolithic and crystalline aerogels of layered double hydroxide (LDH) was performed in a Ni-Al system starting from aqueous ethanol solutions of NiCl2·6H2O and AlCl3·6H2O with acetylacetone as an organic ligand. Propylene oxide as an alkalization reagent was added into precursory solutions to yield monolithic wet gels. The successive pH increase induces the formation of 3-dimentional (3-D) solid framework composed of amorphous Al(OH)3. Then, amphoteric Al(OH)3 undergoes crystallization into Ni-Al LDH via an acetylacetone-driven dissolution-crystallization of metal hydroxides without destroying the preformed 3-D solid framework. The process allows us to obtain crystalline aerogel monoliths with high porosity and high transparency after supercritical CO2 drying of wet gels. The present scheme can be expected to synthesize functionalized aerogel composed of crystalline transition-metal oxide/hydroxides nano-building-blocks.

Determination of Chlorpromazine Hydrochloride with a Layered Double Hydroxide Modified Glassy Carbon Electrode as a Nanocatalyst

AbstractWe report a simple and sensitive voltammetric sensor for the determination of chlorpromazine (CPZ) based on Ni−Al layered double hydroxide (NiAlLDH) modified glassy carbon electrode (GCE). NiAlLDH was simply electrodeposited on GCE surface in a very short time. The response linear range was 1×10−3–1×10−9 mol L−1, with a detection limit of 1×10−9 mol L−1. The NiAlLDH film showed well defined and well separate peaks for dopamine, ascorbic acid, uric acid and CPZ in the same solution. The proposed electrode was used to measure the active pharmaceutical ingredient of CPZ tablet as a real sample.

Electrochromic Thin Films Based on NiAl Layered Double Hydroxide Nanoclusters for Smart Windows and Low-Power Displays

To develop electrochromic thin films for smart windows and low-power displays, homogeneous thin films were produced by spin coating colloidal NiAl layered double hydroxide (LDH) nanocluster solutions on a fluorine-doped tin oxide (FTO) glass substrate. The nano-LDH dispersion was synthesized via a facile one-step epoxide mediated process at room temperature. In situ relative transmittance measurements at 400 nm, recorded during potential scans in cyclic voltammetry or differential pulse chronoamperometry, showed the electrochromic behavior of the homogeneous thin films. The impact of various parameters on the electrochromic properties of the films was detailed, such as the thickness of the film, the nature of the electrolyte, and the presence of electroactive anions. The electrochromic properties, namely, the change in transmittance (ΔT) and the bleaching reversibility, were greatly improved using alkaline metal hydroxide as the electrolyte and in the presence of Fe(CN)64–. The performances that we reached from the deposition of nanoclusters can be advantageously compared to the literature with ΔT = 70% and fast and good reversibility. Upon calcination, the NiAl-LDH film converted into mixed oxides (NiO and NiAl2O4). The higher the calcination temperature, the lower was the ΔT value. The presence of porosity within the thin films, through the introduction of sacrificial polymeric beads and then decomposition at 400 °C, was investigated, highlighting an enhancement of the ΔT value attributed to better accessibility to the nickel redox sites.

In Situ Formation of NiAl-Layered Double Hydroxide with a Tunable Interlayer Spacing in a Confined Impinging Jet Microreactor

This work reports for the first time an in situ synthesis of a NiAl-layered double hydroxide (NiAl-LDH) with a tunable interlayer spacing using a confined impinging jet microreactor (CIJ). It is found that CIJ allows simultaneous guest (water molecules and carbonate) intercalation and in situ growth of NiAl-LDH by imposing a proper micromixing scale in a space-confined mixing chamber. The final interlayer spacing of NiAl-LDH can be easily regulated from 0.9 to 3.6 nm by tuning the Reynolds number flow range from 4.8 × 103 to 6.7 × 102. The supercapacitor has been chosen as a model reaction to investigate the electrochemical activity of NiAl-LDHs. Results demonstrate that a higher interlayer space increases the electrochemical activity and enhances supercapacitor performances due to improvement in space accessibility of NiAl-LDHs during the faradaic redox reaction. NiAl-LDH with an interlayer space up to 3.6 nm presents fairly good performance as a supercapacitor electrode material in terms of specific capacitance (1285.2 F·g–1 at 1 A·g–1) and stability (capacitance retention rates over 80% after 5000 cycles). This work develops a rapid and continuous flow methodology for a one-pot, in situ formation of NiAl-LDH with the controlled interlayer spacing via microreactor technology.

Layered Double Hydroxides for Remediation of Industrial Wastewater from a Galvanic Plant

Owing to their structure, layered double hydroxides (LDHs) are nowadays considered as rising materials in different fields of application. In this work, the results obtained in the usage of two different LDHs to remove, by adsorption, some cationic and anionic pollutants from industrial wastewater are reported. The two compounds MgAl-CO3 and NiAl-NO3 have been prepared through a hydrothermal synthesis process and then characterized by means of PXRD, TGA, FESEM, and FTIR spectroscopy. The available wastewater, supplied by a galvanic treatment company, has been analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES), resulting as being polluted by Fe(III), Cu(II), and Cr(VI). The water treatment with the two LDHs showed that chromate is more efficiently removed by the NiAl LDH through an exchange with the interlayer nitrate. On the contrary, copper and iron cations are removed in higher amounts by the MgAl LDH, probably through a substitution with Mg, even if sorption on the OH− functional groups, surface complexation, and/or precipitation of small amounts of metal hydroxides on the surface of the MgAl LDH could not be completely excluded. Possible applications of the two combined LDHs are also proposed.

Ca–Al, Ni–Al and Zn–Al LDH powders as efficient materials to treat synthetic effluents containing o-nitrophenol

Abstract Powdered layered double hydroxides (LDH) based on calcium-aluminum (Ca–Al), nickel-aluminum (Ni–Al), and zinc-aluminum (Zn–Al) were synthesized with the purpose to evaluate the removal of o-nitrophenol from synthetic effluents by adsorption. It was verified that Ca–Al, Ni–Al, and Zn–Al LDHs presented a typical layered structure confirming the successful synthesis. o-nitrophenol adsorption on the LDH powders was favored at a pH of 5.0, being attained removal percentages from 70 to 90%, depending on the material. Kinetic experimental data obeyed the general order model, while, Sips represented the experimental equilibrium behavior of the three materials adequately. The maximum adsorption capacities were 135.1 mg g−1,122.1 mg g−1 and 130.3 mg g−1 for Ca–Al, Ni–Al, and Zn–Al LDHs, respectively. For simulated effluent, it was attained a removal of up to 60.3% using Ni–Al LDH. In a general way, the layered double hydroxides based on Ca–Al, Ni–Al, and Zn–Al exhibited an interesting potential as adsorbent materials for the treatment of simulated effluents containing o-nitrophenol. Ni–Al is preferred due to its better performance in the treatment of simulated effluents and higher regeneration potential.

Surface area expansion by flower-like nanoscale layered double hydroxides for high efficient stir bar sorptive extraction

Enhancing the surface area of stationary phase is essential in chromatographic science. In this work, nanoscale NiAl-layered double hydroxides (NiAl-LDHs) with flower-like structure was used as a platform for supporting the stationary phase. Then strong hydrophobic p-naphtholbenzein molecule was immobilized onto the LDHs layer as sorbent for stir bar sorptive extraction (SBSE). The flower-like LDHs layer significantly increased the extraction efficiency through increasing the specific surface area and immobilized amounts of stationary phase. In addition, the LDHs can also provide anion exchange ability, which expanded the application of this stir bar for analysis of not only hydrophobic but also anionic analytes. For improving the workability, a poly(ether ether ketone) (PEEK) jacket stir bar with detachable dumbbell-shaped structure was employed. The PEEK jacket with high mechanical strength and dumbbell-shaped structure improved the durability of stir bar and the detectable design allowed elution to be realized with less solvent that enhanced the enrichment factor. The proposed stir bar showed good performance for the extraction of multiple analytes including flavonoids, non-steroid anti-inflammatory drugs and chlorophenoxy acids. By coupling with high performance liquid chromatography-ultraviolet detection (HPLC-UV), the SBSE-HPLC-UV method was applied for the extraction of three active components including bavachin, isobavachalcone and bavachinin in Psoralea corylifolia L. herb with low limit detection of 0.01–0.02 ng/mL.

Tremella-like NiAl-Layered double hydroxides anchored on polydopamine/reduced graphene oxide for supercapacitor with high energy density

The NiAl-layered double hydroxides (NiAl LDHs) has been known as a very desirable positive electrode material for alkaline supercapacitors due to it can provide a higher theoretical specific capacity than β-Ni(OH)2. However, NiAl LDHs is structurally unstable in an alkaline solution and can easily convert into another crystal (β-Ni(OH)2). Therefore, it is important to study and design the true active phase of the effective electrode material. In this work, we use high-valence Al ions to replace some of the Ni ions in the raw materials to stabilize its crystal structure and prepare the tremella-like NiAl LDHs decorated on polydopamine/reduced graphene oxide (NiAl LDHs@PDA/rGO) by a simple hydrothermal method. The NiAl LDHs@PDA/rGO exhibit high specific capacitance of 2210.7 F g−1 at 1 A g−1 and excellence rate performance (71% of capacitance retention with the increase of current density from 1 to 40 A g−1) as the cathode material for supercapacitor. Furthermore, the hybrid supercapacitor delivers a superior energy density of 58.93 W h Kg−1 at 800.21 W kg−1 and long cycling life. This work not only provides a simple method to prepare the tremella-like NiAl LDHs@PDA/rGO but also paves the way for the development of advanced cathode materials for the next generation of supercapacitors.

Effect of intercalated anions on the electrical and dielectric properties of NiAl-X layered double hydroxide ($$\text {X}\, =\, \text {CO}_{3}^{2-}$$, $$\text {NO}_{3}^{-}$$ and $$\text {H}_{2}\text {PO}_{4}^{-})$$: investigation by impedance spectroscopy

This paper reports the effect of interlayer species on the electrical and dielectric behaviours of a lamellar structure. The successful intercalation of three oxyanions ( $$\text {CO}_{3}^{2-}$$ , $$\text {NO}_{3}^{-}$$ and $$\text {H}_{2}\text {PO}_{4}^{-})$$ in the interlayer space of NiAl-layered double hydroxide (LDH) was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma. Using complex impedance spectroscopy measurements, equivalent circuit consisting of three serially connected R-CPE units was established for each sample. Each unit contains a resistance and a constant phase element representing contributions of grain, grain boundary and electrode interface, which allowed the determination of their electrical parameters. The adjustment of experimental data of conductivity by the double power law allowed the determination of $$\sigma _{\mathrm {dc}}$$ and other conductivity parameters, and therefore, the investigation of the effect of intercalated anions on NiAl LDH electrical behaviour. Indeed, dihydrogenophosphates intercalated sample was found to decrease $$\sigma _{\mathrm {ac}}$$ over the frequency range of measure, comparing to the other anions. The intercalation of this anion has also an effect on dielectric properties, it reduces the value of dielectric constant of NiAl LDH, and shifts the maximum of tan $$\delta $$ towards medium frequencies with a decrease in the value of loss tangent above $$10^{5}$$ Hz. Carbonate and nitrate intercalated LDH showed a similarity in their effect on electrical and dielectric properties of NiAl LDH.

Flower-like layered double hydroxide-modified stainless-steel fibers for online in-tube solid-phase microextraction of Sudan dyes.

Layered double hydroxides are a family of inorganic crystals that have gained a lot of attention due to its special structure and properties such as high porosity, large specific area, and excellent anion exchange ability. In this work, flower-like NiAl-layered double hydroxides with high specific area were in situ immobilized onto the stainless steel fibers by bioinspired polydopamine modification method and packed into poly (ether ether) ketone tube for online solid-phase microextraction with high performance liquid chromatography analysis. Thanks to the high specific surface area and excellent extraction ability of the NiAl-layered double hydroxides, the fibers showed excellent extraction performance to three Sudan dyes with enrichment factors between 260 to 650 folds. After optimization of the reaction and extraction conditions, an online solid-phase microextraction method was developed for determination of Sudan dyes in water samples and chili samples. The method has limits of detection of 0.01 to 0.02ng/mL, good linearity and good reproducibility (≤1.45%).

Chlorpromazine Electro‐oxidation at BDD Electrode Modified with nZVI Nanoparticles Impregnated NiAl LDH

AbstractNanocomposite of nanoscale zero‐valent iron (nZVI) and layered double hydroxide (LDH) was used as modifier for boron‐doped diamond electrode in determination of anti‐psychotic drug chlorpromazine (CPZ). nZVI nanoparticles were prepared by liquid phase reduction of ferric chloride with sodium borohydride on the surface of NiAl LDH matrix owing to the strong exchange and confinement efficiency of LDH. The structure, binding and surface properties of the nZVI@LDH nanocomposite were monitored using powder X‐ray diffractometry, FT‐IR spectroscopy, scanning and transmission microscopy and BET techniques. The electrochemical properties of the modified electrode were investigated by CV and EIS, performed in a phosphate buffer containing ferro/ferricyanide as redox probe. The modified electrode exhibited excellent electrochemical performance compared with unmodified electrode. As regard potential application of the nanocomposite surface to the CPZ detection, square‐wave voltammetric signals showed a good linear correlation over CPZ concentrations in a broad range from 0.1 to 8.0 μM with low detection limit of 0.005 μM. Nevertheless, these results suggest that the proposed nanocomposite modifier surface provides exceptional synergy and significant enhancement effect to the voltammetric response of CPZ and thus could be applied as highly efficient and stable platform of sensors in clinical analysis.

Surface charge density-dependent performance of Ni–Al layered double hydroxide-based flexible self-powered generators driven by natural water evaporation

Natural water evaporation (NWE) can be used as a driving force to generate electricity. NWE-driven generators (NWEGs) require materials with charged surfaces. However, the quantitative adjustment of the surface charge density (dc) remains difficult and the relationship between dc and NWEG performance has not been clarified. Herein, Ni–Al layered double hydroxide (LDH) films with tailored structural dc in the range of 2.52–4.59 e/nm2 were synthesized by precisely adjusting the molar ratio of Al3+ to Ni2+. The Ni–Al LDH films were assembled into NWEGs by the spraying method and then their electrical performance was investigated. Strong positive correlations were observed between dc, open-circuit voltage (Voc), and short-circuit current (Isc); that is, the larger dc, the higher Voc and Isc. The maximum Voc of ~0.6 V, Isc of ~0.3 μA, and output power density of ~15 μW/cm3 were achieved simultaneously for a 4 × 1.5 cm NWEG with a maximum dc of 4.59 e/nm2. A reasonable increase of dc resulted in improved device performance, which was attributed to the positive correlation between the densities of both hydroxide ions in the diffusion layer and positive charge on the Ni–Al LDH film surface. In addition, a relatively stable total Voc of ~2.5 V and Isc of ~1.5 μA were obtained using eight NWEGs with a modified individual generator structure. The eight assembled NWEGs successfully powered a simple electronic watch. The spraying method used to fabricate the NWEGs not only greatly shortened the device molding time, but also markedly improved device stability. This study reveals a new avenue to guide the design of materials and to improve the performance of flexible self-powered NWEGs.

Intercalation Effect in NiAl-layered Double Hydroxide Nanosheets for CO2 Reduction Under Visible Light

Photocatalytic reduction of CO2(CO2PR) to valuable solar fuels is considered as a promising route to the amelioration of fossil fuel conundrum and the mitigation of greenhouse gases. Although progress has been made to enhance CO2PR performance, the available method that can promote the selectivity of CO2PR products remains to be a challenge. In this work, we synthesized NO3− or CO32− intercalated NiAl-layered double hydroxide(NiAl-LDH) photocatalysts and investigated the performance of CO2PR in the presence of an electron donor and a photosensitizer. Compared with Ni2Al-CO32−, Ni2Al-NO3− exhibited superior catalytic performance in the CO2PR, and the resulted selectivity of CH4 in Ni2Al-NO3−(6.1%) was 12.2 times that of Ni2Al-CO32−(0.5%) under visible light irradiation. X-Ray absorption fine structure(XAFS) result reveals a relative abundance of defects in Ni2Al-NO3−, which played as active sites and promoted charge transfer in CO2PR for the efficient CH4 evolution.

Catalytically Active Oil-Based Lubricant Additives Enabled by Calcining Ni-Al Layered Double Hydroxides.

Layered double hydroxides (LDHs) have lately been hailed as robust lubricant additives for improving tribological properties and as ideal catalysts for synthesizing carbon-based nanomaterials. In this paper, in situ analytical tools are used to track the evolution of the crystal structure and chemical composition of LDHs during calcination. Nickel oxide and elemental nickel can be produced by calcining NiAl-LDH in air (LDH-C-Air) and argon (LDH-C-Ar), respectively. For the base oil with 1 wt % LDH-C-Air, negligible wear can be detected even after a 2 h friction test under a severe contact pressure (∼637 MPa). A relatively thick tribofilm (∼60 nm) with a better mechanical property is formed, which protects the solid surface from severe wear. In addition, the possible formed carbon debris may also prevent the direct collision of asperities and effectively improve the wear resistance. This work provides a unique vision for the application of calcined LDHs with the combination of catalysis and tribology.

Ni-Based Catalyst Derived from NiAl Layered Double Hydroxide for Vapor Phase Catalytic Exchange between Hydrogen and Water.

A high-efficient and low-cost catalyst on hydrogen isotope separation between hydrogen and water is an essential factor in industrial application for heavy water production and water detritiation. In past studies, Pt-based catalysts were developed but not practical for commercial use due to their high cost for vapor phase catalytic exchange (VPCE), while for impregnated nickel catalysts with a lower cost the problems of agglomeration and low Ni utilization existed. Therefore, to solve these problems, in-situ grown Ni-based catalysts (NiAl-LDO) derived from a layered double hydroxide (LDH) precursor were fabricated and first applied in VPCE in this work. Compared with traditional impregnated Ni-based catalysts, NiAl-LDO catalysts own a unique layered structure, homogeneous dispersed metallic phase, higher specific surface area as well as stronger metal-support interactions to prevent active metal from agglomerating. These advantages are beneficial for exposing more active sites to improve dynamic contacts between H2 and HDO in a catalyst surface and can bring excellent catalytic activity under a reaction temperature of lower than 400 °C. Additionally, we found that the dissociative chemisorption of HDO and H2 occurs not only in Ni (111) but also in NiO species where chemisorbed H(ads), D(ads), OH(ads) and OD(ads) are formed. The results highlight that both of the Ni2+ species and Ni0 species possess catalytic activities for VPCE process.

A Novel Sensitive Doxorubicin Hydrochloride Electrochemical Sensor Based on a Nickel Hexacyanoferrate/Ni-Al-LDH Modified Gold Electrode.

A highly sensitive and selective electrochemical sensor has been fabricated by the electrodepositing of nickel hexacyanoferrate (NiHCF) on a Ni-Al layered double hydroxides (Ni-Al-LDH) modified Au electrode for the quantification of doxorubicin hydrochloride (DOX). The characterization of synthesized nanomaterials has been conducted by scanning electron microscopy, energy dispersive X-ray spectroscopy and electrochemical methods. The synergistic effect of NiHCF and Ni-Al-LDH not only excellently improves the performance of DOX electro-reduction, but also promotes electron transfer between DOX and the NiHCF/Ni-Al-LDH/Au sensor. The differential pulse voltammetric response of the NiHCF/Ni-Al-LDH/Au sensor shows a linear relationship with the concentration of DOX in the range of 1.0 × 10-8 - 6.2 × 10-6 mol L-1, a limit of detection of 1.9 × 10-9 mol L-1 (S/N = 3) and a sensibility of 14.71 A mol L-1 cm-2. The developed sensor exhibits good sensitivity, reproducibility, anti-interference and a long-term stability property. Furthermore, the NiHCF/Ni-Al-LDH/Au sensor has been successfully applied to determine DOX in biological samples and human blood serum samples.

NiAl Layered Double Hydroxide Flowers with Ultrathin Structure Grown on 3D Graphene for High‐Performance Supercapacitors

To overcome the low electrical conductivity weakness of layered double hydroxide and to improve the electrochemical energy storage performance as supercapacitor electrodes, NiAl layered double hydroxide (NiAl‐LDH) flowers with ultrathin structure grown on three‐dimensional graphene (3DG) was constructed via a facile hydrothermal strategy. The NiAl‐LDH/3DG composites as binder‐free supercapacitor electrode showed a high specific capacitance of 884.5 F g–1 at 1 A g–1. Excellent cycle stability retaining 90 % of the initial capacitance after 7000 cycles at 5 A g–1 was also demonstrated, with the coulombic efficiency stayed above 95 % during the whole cycling process. The excellent performances should be ascribed to the synergistic effect of NiAl‐LDH and 3DG, in which the NiAl‐LDH ultrathin nanoflake petals provide sufficient pseudocapacitive sites; while 3DG provides robust and highly interconnected skeleton for efficient mass/charge transport.