Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau...Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.展开更多
Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to ...Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to their unique layered and tunable chemical structures and abundant surface hydroxide(OH)moieties,which are hydroxyl radical(OH)precursors.However,the practical applications of LDHs are limited by their poor charge-separation ability and insufficient active sites.Herein,we developed a facile N_(2)H_(4)-driven etching approach to introduce dual Ni^(2+)and OHvacancies(Niv and OHv,respectively)into NiFe-LDH nanosheets(hereafter referred to as NiFe-LDH-et)to facilitate improved charge-carrier separation and active Lewis acidic site(Fe^(3+)and Ni^(2+)exposed at OHv)formation.In contrast to inert pristine LDH,NiFe-LDH-et actively removed NO under visible-light illumination.Specifically,Ni_(76)Fe_(24)-LDH-et etched with 1.50 mmol·L^(-1)N_(2)H_(4)solution removed 32.8%of the NO in continuously flowing air(NO feed concentration:500 parts per billion(ppb))under visible-light illumination,thereby outperforming most reported catalysts.Experimental and theoretical data revealed that the dual vacancies promoted the production of reactive oxygen species(O_(2)·^(-)andOH)and the adsorption of NO on the LDH.In situ spectroscopy demonstrated that NO was preferentially adsorbed at Lewis acidic sites,particularly exposed Fe^(3+)sites,converted into NO+,and subsequently oxidized to NO3without the notable formation of the more toxic intermediate NO2,thereby alleviating risks associated with its production and emission.展开更多
Modulating metal-organic framework’s(MOF)crystallinity and size using a polymer,in conjunction with a high surface area of layered double hydroxide,yields an effective strategy for concurrently enhancing the electroc...Modulating metal-organic framework’s(MOF)crystallinity and size using a polymer,in conjunction with a high surface area of layered double hydroxide,yields an effective strategy for concurrently enhancing the electrochemical and photocatalytic performance.In this study,we present the development of an optimized nanocomposite,denoted as 0.5PVP/ZIF-67,developed on AZ31 magnesium alloy,serving as an efficient and durable multifunctional coating.This novel strategy aims to enhance the overall performance of the porous coating through the integration of microarc oxidation(MAO),ZnFe LDH backbone,and ZIF-67 formation facilitated by the addition of polyvinylpyrrolidone(PVP),resulting in a three-dimensional,highly efficient,and multifunctional material.The incorporation of 0.5 g of PVP proved to be effective in the size modulation of ZIF-67,which formed a corrosion-resistant top layer,improving the total polarization resistance(R_(p)=8.20×10^(8)).The dual functionality exhibited by this hybrid architecture positions it as a promising candidate for mitigating environmental pollution,degrading 97.93%of Rhodamine B dye in 45 min.Moreover,the sample displayed exceptional degradation efficiency(96.17%)after 5 cycles.This study illuminates the potential of nanocomposites as electrochemically stable and photocatalytically active materials,laying the foundation for the advancements of next-generation multifunctional frameworks.展开更多
Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particul...Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particularly Mg-based LDHs,rank among the most prevalent two-dimensional materials utilized in separation processes,which include adsorption,extraction,and membrane technology.The high popularity of Mg-based LDHs in separation applications can be attributed to their properties,such as excellent hydrophilicity,high surface area,ion exchangeability,and adjustable interlayer space.Currently,polymer membranes play a pivotal role in semi-industrial and industrial separation processes.Consequently,the development of polymer membranes and the mitigation of their limitations have emerged as compelling topics for researchers.Several methods exist to enhance the separation performance and anti-fouling properties of polymer membranes.Among these,incorporating additives into the membrane polymer matrix stands out as a cost-effective,straightforward,readily available,and efficient approach.The use of Mg-based LDHs,either in combination with other materials or as a standalone additive in the polymer membrane matrix,represents a promising strategy to bolster the separation and anti-fouling efficacy of flat sheet mixed matrix polymer membranes.This review highlights Mg-based LDHs as high-potential additives designed to refine flat sheet mixed matrix polymer membranes for applications in wastewater treatment and brackish water desalination.展开更多
Dry milling followed by ultrasonic irradiation in the presence of small amounts of aqueous NaOH, was used to synthesise ZnAl-layered double hydroxide （LDH）. The synthetic conditions were optimised and the Zn（OH）2,...Dry milling followed by ultrasonic irradiation in the presence of small amounts of aqueous NaOH, was used to synthesise ZnAl-layered double hydroxide （LDH）. The synthetic conditions were optimised and the Zn（OH）2, ZnO, and AI（OH）3 contaminants were removed by rinsing with aqueous NH3 solution from the sample prepared in the optimum conditions. Thus, phase-pure ZnAl-layered double hydroxide was obtained with high crystallinity. All materials produced during the syntheses were characterised by X- ray diffractometry, and a rose-like morphology was observed by scanning electron microscopy in the phase-pure sample. By changing the initial Zn/Al ratio, it was revealed that an LDH with low zinc content was always formed, probably through substitution of some of the Zn2. ions by AI3. ions in the gibbsite lattice.展开更多
In this study, new nano spherical graphene modified with LDH(Layered Double Hydroxide) was prepared and used to remove As(Ⅲ) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a ...In this study, new nano spherical graphene modified with LDH(Layered Double Hydroxide) was prepared and used to remove As(Ⅲ) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a well-known Hammer method. The obtained graphene oxide solution was sprayed in octanol solution under different temperatures and sprayed speed as influenced variables. The structure and physical characterization of synthesized spherical graphene oxide were determined by various techniques,including FT-IR, N_(2) adsorption–desorption, SEM, TEM, and EDX. In the next step, the hydrothermal method was applied to deposition LDH on the spherical graphene oxide. The synthesized spherical graphene modified by LDH was used to remove As(Ⅲ) as a toxic heavy metal ion. The effect of influenced variables including p H, contact time, amount of sorbent, and type eluent studied and the optimum values were as 8, 30, 50, and HCl(0.5 mol·L^(-1)), respectively. After optimization, the studied sorbent was shown a high adsorption capacity(149.3 mg·g^(-1)). The adsorption mechanism and kinetic models exhibited good agreement with the Langmuir isotherm and pseudo-second-order trends, respectively. Besides, the synthesized product was tested for seven times without significant loss in its sorption efficiency.展开更多
To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on ele...To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.展开更多
Electrochemical CO_(2)reduction into energy-carrying compounds,such as formate,is of great importance for carbon neutrality,which however suffers from high electrical energy input and liquid products crossover.Herein,...Electrochemical CO_(2)reduction into energy-carrying compounds,such as formate,is of great importance for carbon neutrality,which however suffers from high electrical energy input and liquid products crossover.Herein,we fabricated self-supported ultrathin NiCo layered double hydroxides(LDHs)electrodes as anode for methanol electrooxidation to achieve a high formate production rate(5.89 mmol h^(-1)cm^(-2))coupled with CO_(2)electro-reduction at the cathode.A total formate faradic efficiency of both anode for methanol oxidation and cathode for CO_(2)reduction can reach up to 188%driven by a low cell potential of only 2.06 V at 100 mA cm^(-2)in membrane-electrode assembly(MEA).Physical characterizations demonstrated that Ni^(3+)species,formed on the electrochemical oxidation of Ni-containing hydroxide,acted as catalytically active species for the oxidation of methanol to formate.Furthermore,DFT calculations revealed that ultrathin LDHs were beneficial for the formation of Ni^(3+)in hydroxides and introducing oxygen vacancy in NiCo-LDH could decrease the energy barrier of the rate-determining step for methanol oxidation.This work presents a promising approach for fabricating advanced electrodes towards electrocatalytic reactions.展开更多
Layered double hydroxide(LDH)coatings on magnesium(Mg)alloys shine brightly in the field of corrosion protection because of their special ion-exchange function.State-of-the-art steam coating as a type of LDH film prep...Layered double hydroxide(LDH)coatings on magnesium(Mg)alloys shine brightly in the field of corrosion protection because of their special ion-exchange function.State-of-the-art steam coating as a type of LDH film preparation technique has emerged in recent years because only pure water is required as the steam source and its environmentally friendly LDH coating fits the current need for green development.Moreover,this coating can effectively inhibit the corrosion of the Mg alloy substrate due to the chemical bonding between the coating and the Mg alloy substrate.This review systematically explains cutting-edge advancements in the growth mechanism and corrosion behavior of LDH steam coatings,and analyzes the advantages and limitations of the steam-coating method.The influencing factors including pressure,CO_(2)/CO_(3)^(2-),aluminum content of the substrate alloy,solution type,and acid-pickling pretreatment,as well as the post-treatment of steam-coating defects,are comprehensively elucidated,providing new insights into the development of the in situ steam-coating technique.Finally,existing issues and future prospects are discussed to further accelerate the widespread application of Mg alloys.展开更多
1-Tetralone, a useful synthetic intermediate in the manufacture of pharmaceuticals, agrochemicals and dyes, can be prepared by liquid phase catalytic oxidation of tetralin. Selective oxidation of tetralin to 1-tetralo...1-Tetralone, a useful synthetic intermediate in the manufacture of pharmaceuticals, agrochemicals and dyes, can be prepared by liquid phase catalytic oxidation of tetralin. Selective oxidation of tetralin to 1-tetralone is still a big challenge with low-temperature processes using environmentally friendly routes even after decades of research. Herein, we demonstrate room-temperature oxidation of tetralin to 1-tetralone over layered double hydroxide-hosted sulphonato-salen-nickel(II) complex, LDH-[Ni-salen]. The layered double hydroxide-hosted sulphonato-salen-nickel(II) compound was characterized by powder X-ray diffraction, Fourier transform infrared spectrometer (FTIR), UV-Visible diffuse reflectance spectra, scanning electron microscopy (SEM) and elemental analysis. The theoretical calculations of free sulphonato-salen-nickel(II) complex using Density Functional Theory/CAM-B3LYP at the 6-311++ G(d,p) level of theory were also used to determine the orientation of the Ni-salen compound within the layered structure. The immobilized compound, LDH-[Ni-salen] was found to be an effective reusable catalyst for the oxidation of tetralin to 1-tetralone using a combination of trimethylacetaldehyde and molecular oxygen (14.5 psi) and at 25°C. At 45.5% conversion, tetralin was converted to 1-tetralone with 77.2% selectivity at room temperature and atmospheric pressure after 24 h. The catalyst recycles test and hot filtration experiment showed that oxidation proceeded through Ni(II) sites in LDH-[Ni-salen]. The catalysts were reused several times without losing their catalytic activity and selectivity. The present results may provide a convenient strategy for the preparation of 1-tetralone using layered double hydroxide-based heterogeneous catalyst at ambient temperature for industrial application in near future.展开更多
Bimetallic compounds such as hydrotalcite-type layered double hydroxides(LDHs)are promising electrocatalysts owing to their unique electronic structures.However,their abilities toward nitrogen adsorption and reduction...Bimetallic compounds such as hydrotalcite-type layered double hydroxides(LDHs)are promising electrocatalysts owing to their unique electronic structures.However,their abilities toward nitrogen adsorption and reduction are undermined since the surface-mantled,electronegative-OH groups hinder the charge transfer between transition metal atoms and nitrogen molecules.Herein,a smart interfacing strategy is proposed to construct a coupled heterointerface between LDH and 2D g-C_(3)N_(4),which is proven by density functional theory(DFT)investigations to be favorable for nitrogen adsorption and ammonia desorption compared with neat LDH surface.The interfaced LDH and g-C_(3)N_(4) is further hybridized with a self-standing TiO_(2) nanofibrous membrane(NM)to maximize the interfacial effect owing to its high porosity and large surface area.Profited from the synergistic superiorities of the three components,the LDH@C_(3)N_(4)@TiO_(2) NM delivers superior ammonia yield(2.07×10^(−9) mol s^(−1) cm^(−2))and Faradaic efficiency(25.3%),making it a high-efficiency,noble-metal-free catalyst system toward electrocatalytic nitrogen reduction.展开更多
Layered double hydroxides(LDHs) have attracted considerable attention as a cost effective alternative to the precious iridium-and ruthenium-based electrocatalysts for an oxygen evolution reaction(OER),a bottleneck of ...Layered double hydroxides(LDHs) have attracted considerable attention as a cost effective alternative to the precious iridium-and ruthenium-based electrocatalysts for an oxygen evolution reaction(OER),a bottleneck of water electrolysis for sustainable hydrogen production.Despite their excellent OER performance,the structural and electronic properties of LDHs,particularly during the OER process,remain to be poorly understood.In this study,a series of LDH catalysts is investigated through in situ X-ray absorption fine structure analyses and density functional theory(DFT) calculations.Our experimental results reveal that the LDH catalyst with equal amounts of Ni and Fe(NF-LDH) exhibits the highest OER activity and catalytic life span when compared with its counterparts having equal amounts of Ni and Co(NC-LDH)and Ni only(Ni-LDH).The NF-LDH shows a markedly enhanced OER kinetics compared to the NC-LDH and the Ni-LDH,as proven by the lower overpotentials of 180,240,and 310 mV,respectively,and the Tafel slopes of 35.1,43.4,and 62.7 mV dec^(-1),respectively.The DFT calculations demonstrate that the lowest overpotential of the NF-LDH is associated with the active sites located at the edge planes of NF-LDH in contrast to those located at the basal planes of Ni-LDH and NC-LDH.The current study pinpoints the active sites on various LDHs and presents strategies for optimizing the OER performance of the LDH catalysts.展开更多
ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered d...ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.展开更多
Layered double Mg-Fe-CO3 hydroxide （Mg-Fe-LDH） with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg-Fe-CLDH was obtained by heating Mg-Fe-LDH at 500 ℃ for 6 h. The as...Layered double Mg-Fe-CO3 hydroxide （Mg-Fe-LDH） with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg-Fe-CLDH was obtained by heating Mg-Fe-LDH at 500 ℃ for 6 h. The as prepared Mg-Fe-LDH and calcined Mg-Fe-CLDH were used for removal of glutamic acid （Glu） from aqueous solution, respectively. Batch studies were carried out to address various experimental parameters such as contact time, pH, initial glutamic acid （Glu） concentration, co-existing anions and temperature. Glu was removed effectively （99.9%） under the optimized experimental conditions with Mg-Fe-CLDH. The adsorption kinetics follows the Ho’s pseudo second-order model. Isotherms for adsorption with Mg-Fe-CLDH at different solution temperatures were well described using the Langmuir model with a good correlation coefficient. The intraparticle diffusion model fitted the data well, which suggests that the intraparticle diffusion is not only the rate-limiting step.展开更多
Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773...Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773 K for 6 h. Removal of vanadate anion （ 3-4VO ） from aqueous solution on CLDH2 was studied. Batch studies were carried out to address various experimental parameters such as Mg/Al molar ratio, adsorbent dosage, initial concentration of solution, contact time and temperature. Vanadate was removed effectively at the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-first-order model. Isotherms for adsorption vanadate by CLDH2 at different solution temperatures were well described using the Langmuir and Freundlich equations, and the isotherm parameters were calculated using linear regression analysis. The adsorption data fitted the langmuir model with good values of the correlation coefficient （R2〉0.999）. The negative value ofΔGΘand the positive value ofΔHΘindicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption suggests that the surface adsorption is the main process.展开更多
Colored layered double hydroxides （LDHs） can be synthesized by introducing colored cations such as Fe^3＋ and Cr^3 ＋, which call be used as thermal stabilizers for polyvinyl chloride （PVC）. The yellowish Mg/Fe an...Colored layered double hydroxides （LDHs） can be synthesized by introducing colored cations such as Fe^3＋ and Cr^3 ＋, which call be used as thermal stabilizers for polyvinyl chloride （PVC）. The yellowish Mg/Fe and bluish Mg/Cr LDHs are prepared by the co-precipitation method. The results show that the MgsCr_ CO3 and Mg3Fe_ CO3 colored layered double hydroxides can stabilize PVC for more than 30 min under the thermal aging temperature of 180 ℃. The preparation can use cheap Mg（OH） 2 instead of MgCl2, which produces a much smaller amount of the by-product NH4Cl. It is known that NH4Cl is a cheap fertilizer that is difficult to sell; therefore, the preparation is much greener and more economic than the one using magnesium salt.展开更多
For many two-dimensional(2D)materials,low coordination edges and corner sites offer greatly enhanced catalytic performance compared to basal sites,motivating the search for new synthetic approaches towards ultrathin a...For many two-dimensional(2D)materials,low coordination edges and corner sites offer greatly enhanced catalytic performance compared to basal sites,motivating the search for new synthetic approaches towards ultrathin and ultrafine 2D nanomaterials with high specific surface areas.To date,the synthesis of catalysts that are both ultrathin(monolayer)and ultrafine(lateral size<10nm)has proven extremely challenging.Herein,using a facile ultrasonic exfoliation procedure,we describe the successful synthesis of ultrafine ZnCo-LDH nanosheets(denoted as ZnCo-UF)with a size^3.5 nm and thickness^0.5 nm.The single layer ZnCo-UF nanosheets possess an abundance of oxygen vacancies(Vo)and unsaturated coordination s让es,thereby affording outstanding electrocatalytic water oxidation performance.DFT calculations confirmed that Vo on the surface of ZnCo-UF enhanced H20 adsorption via increasing the electropositivity of the nanosheets.展开更多
With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1]...With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1],fuel cells[2]and water splitting devices[3].Electrocatalytic oxidation of water to O2(oxygen evolution reaction,OER)is a vital chemical process involved in energy storage and conversion from renewable sources in form of molecular fuels such as H2 via water electrolysis,which has attracted a great amount of research efforts in the past few years[4,5].Nowadays,RuO2 and IrO2 are widely used as typical excellent OER electrocatalysts.However,their high-cost and scarce nature restricts the broadly commercial application of those materials[6,7].Hence,there is an urgent demand to develop low cost,highly efficient,and superb stable OER catalysts.展开更多
The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water sp...The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides（LDHs） and their derivatives（e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides） have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.展开更多
Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen...Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen evolution reaction(OER)due to their layered structure combined with versatile com-positions.Furthermore,reducing the thickness of platelet LDH crystals to nanometer or even molecular scale via cleavage or delamination provides an important clue to enhance the activity.In this review,recent progresses on rational design of LDH nanosheets are reviewed,including direct synthesis via traditional coprecipitation,homogeneous precipitation,and newly developed topochemical oxidation as well as chemical exfoliation of parent LDH crystals.In addition,diverse strategies are introduced to modulate their electrochemical activity by tuning the composition of host metal cations and intercalated counter-anions,and incorporating dopants,cavi-ties,and single atoms.In particular,hybridizing LDHs with conductive components or in situ growing them on conductive substrates to produce freestanding electrodes can further enhance their intrinsic catalytic activity.A brief discussion on future research directions and prospects is also summarized.展开更多
基金support from the Free Exploration Project of Frontier Technology for Laoshan Laboratory(No.16-02)the National Natural Science Foundation of China(Nos.22072015 and 21927811)。
文摘Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.
基金the supports from Debris of the Anthropocene to Resources(DotA2)Lab at NTU.
文摘Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to their unique layered and tunable chemical structures and abundant surface hydroxide(OH)moieties,which are hydroxyl radical(OH)precursors.However,the practical applications of LDHs are limited by their poor charge-separation ability and insufficient active sites.Herein,we developed a facile N_(2)H_(4)-driven etching approach to introduce dual Ni^(2+)and OHvacancies(Niv and OHv,respectively)into NiFe-LDH nanosheets(hereafter referred to as NiFe-LDH-et)to facilitate improved charge-carrier separation and active Lewis acidic site(Fe^(3+)and Ni^(2+)exposed at OHv)formation.In contrast to inert pristine LDH,NiFe-LDH-et actively removed NO under visible-light illumination.Specifically,Ni_(76)Fe_(24)-LDH-et etched with 1.50 mmol·L^(-1)N_(2)H_(4)solution removed 32.8%of the NO in continuously flowing air(NO feed concentration:500 parts per billion(ppb))under visible-light illumination,thereby outperforming most reported catalysts.Experimental and theoretical data revealed that the dual vacancies promoted the production of reactive oxygen species(O_(2)·^(-)andOH)and the adsorption of NO on the LDH.In situ spectroscopy demonstrated that NO was preferentially adsorbed at Lewis acidic sites,particularly exposed Fe^(3+)sites,converted into NO+,and subsequently oxidized to NO3without the notable formation of the more toxic intermediate NO2,thereby alleviating risks associated with its production and emission.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘Modulating metal-organic framework’s(MOF)crystallinity and size using a polymer,in conjunction with a high surface area of layered double hydroxide,yields an effective strategy for concurrently enhancing the electrochemical and photocatalytic performance.In this study,we present the development of an optimized nanocomposite,denoted as 0.5PVP/ZIF-67,developed on AZ31 magnesium alloy,serving as an efficient and durable multifunctional coating.This novel strategy aims to enhance the overall performance of the porous coating through the integration of microarc oxidation(MAO),ZnFe LDH backbone,and ZIF-67 formation facilitated by the addition of polyvinylpyrrolidone(PVP),resulting in a three-dimensional,highly efficient,and multifunctional material.The incorporation of 0.5 g of PVP proved to be effective in the size modulation of ZIF-67,which formed a corrosion-resistant top layer,improving the total polarization resistance(R_(p)=8.20×10^(8)).The dual functionality exhibited by this hybrid architecture positions it as a promising candidate for mitigating environmental pollution,degrading 97.93%of Rhodamine B dye in 45 min.Moreover,the sample displayed exceptional degradation efficiency(96.17%)after 5 cycles.This study illuminates the potential of nanocomposites as electrochemically stable and photocatalytically active materials,laying the foundation for the advancements of next-generation multifunctional frameworks.
文摘Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particularly Mg-based LDHs,rank among the most prevalent two-dimensional materials utilized in separation processes,which include adsorption,extraction,and membrane technology.The high popularity of Mg-based LDHs in separation applications can be attributed to their properties,such as excellent hydrophilicity,high surface area,ion exchangeability,and adjustable interlayer space.Currently,polymer membranes play a pivotal role in semi-industrial and industrial separation processes.Consequently,the development of polymer membranes and the mitigation of their limitations have emerged as compelling topics for researchers.Several methods exist to enhance the separation performance and anti-fouling properties of polymer membranes.Among these,incorporating additives into the membrane polymer matrix stands out as a cost-effective,straightforward,readily available,and efficient approach.The use of Mg-based LDHs,either in combination with other materials or as a standalone additive in the polymer membrane matrix,represents a promising strategy to bolster the separation and anti-fouling efficacy of flat sheet mixed matrix polymer membranes.This review highlights Mg-based LDHs as high-potential additives designed to refine flat sheet mixed matrix polymer membranes for applications in wastewater treatment and brackish water desalination.
文摘Dry milling followed by ultrasonic irradiation in the presence of small amounts of aqueous NaOH, was used to synthesise ZnAl-layered double hydroxide （LDH）. The synthetic conditions were optimised and the Zn（OH）2, ZnO, and AI（OH）3 contaminants were removed by rinsing with aqueous NH3 solution from the sample prepared in the optimum conditions. Thus, phase-pure ZnAl-layered double hydroxide was obtained with high crystallinity. All materials produced during the syntheses were characterised by X- ray diffractometry, and a rose-like morphology was observed by scanning electron microscopy in the phase-pure sample. By changing the initial Zn/Al ratio, it was revealed that an LDH with low zinc content was always formed, probably through substitution of some of the Zn2. ions by AI3. ions in the gibbsite lattice.
文摘In this study, new nano spherical graphene modified with LDH(Layered Double Hydroxide) was prepared and used to remove As(Ⅲ) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a well-known Hammer method. The obtained graphene oxide solution was sprayed in octanol solution under different temperatures and sprayed speed as influenced variables. The structure and physical characterization of synthesized spherical graphene oxide were determined by various techniques,including FT-IR, N_(2) adsorption–desorption, SEM, TEM, and EDX. In the next step, the hydrothermal method was applied to deposition LDH on the spherical graphene oxide. The synthesized spherical graphene modified by LDH was used to remove As(Ⅲ) as a toxic heavy metal ion. The effect of influenced variables including p H, contact time, amount of sorbent, and type eluent studied and the optimum values were as 8, 30, 50, and HCl(0.5 mol·L^(-1)), respectively. After optimization, the studied sorbent was shown a high adsorption capacity(149.3 mg·g^(-1)). The adsorption mechanism and kinetic models exhibited good agreement with the Langmuir isotherm and pseudo-second-order trends, respectively. Besides, the synthesized product was tested for seven times without significant loss in its sorption efficiency.
基金the National Natural Science Foundation of China(NSFC Grant No.62174152).
文摘To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.
基金the financial support from the National Nature Science Foundation of China(22078232 and 21938008)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Electrochemical CO_(2)reduction into energy-carrying compounds,such as formate,is of great importance for carbon neutrality,which however suffers from high electrical energy input and liquid products crossover.Herein,we fabricated self-supported ultrathin NiCo layered double hydroxides(LDHs)electrodes as anode for methanol electrooxidation to achieve a high formate production rate(5.89 mmol h^(-1)cm^(-2))coupled with CO_(2)electro-reduction at the cathode.A total formate faradic efficiency of both anode for methanol oxidation and cathode for CO_(2)reduction can reach up to 188%driven by a low cell potential of only 2.06 V at 100 mA cm^(-2)in membrane-electrode assembly(MEA).Physical characterizations demonstrated that Ni^(3+)species,formed on the electrochemical oxidation of Ni-containing hydroxide,acted as catalytically active species for the oxidation of methanol to formate.Furthermore,DFT calculations revealed that ultrathin LDHs were beneficial for the formation of Ni^(3+)in hydroxides and introducing oxygen vacancy in NiCo-LDH could decrease the energy barrier of the rate-determining step for methanol oxidation.This work presents a promising approach for fabricating advanced electrodes towards electrocatalytic reactions.
基金This work was supported by the National Natural Science Foundation of China through the projects 51601108 and 52071191。
文摘Layered double hydroxide(LDH)coatings on magnesium(Mg)alloys shine brightly in the field of corrosion protection because of their special ion-exchange function.State-of-the-art steam coating as a type of LDH film preparation technique has emerged in recent years because only pure water is required as the steam source and its environmentally friendly LDH coating fits the current need for green development.Moreover,this coating can effectively inhibit the corrosion of the Mg alloy substrate due to the chemical bonding between the coating and the Mg alloy substrate.This review systematically explains cutting-edge advancements in the growth mechanism and corrosion behavior of LDH steam coatings,and analyzes the advantages and limitations of the steam-coating method.The influencing factors including pressure,CO_(2)/CO_(3)^(2-),aluminum content of the substrate alloy,solution type,and acid-pickling pretreatment,as well as the post-treatment of steam-coating defects,are comprehensively elucidated,providing new insights into the development of the in situ steam-coating technique.Finally,existing issues and future prospects are discussed to further accelerate the widespread application of Mg alloys.
文摘1-Tetralone, a useful synthetic intermediate in the manufacture of pharmaceuticals, agrochemicals and dyes, can be prepared by liquid phase catalytic oxidation of tetralin. Selective oxidation of tetralin to 1-tetralone is still a big challenge with low-temperature processes using environmentally friendly routes even after decades of research. Herein, we demonstrate room-temperature oxidation of tetralin to 1-tetralone over layered double hydroxide-hosted sulphonato-salen-nickel(II) complex, LDH-[Ni-salen]. The layered double hydroxide-hosted sulphonato-salen-nickel(II) compound was characterized by powder X-ray diffraction, Fourier transform infrared spectrometer (FTIR), UV-Visible diffuse reflectance spectra, scanning electron microscopy (SEM) and elemental analysis. The theoretical calculations of free sulphonato-salen-nickel(II) complex using Density Functional Theory/CAM-B3LYP at the 6-311++ G(d,p) level of theory were also used to determine the orientation of the Ni-salen compound within the layered structure. The immobilized compound, LDH-[Ni-salen] was found to be an effective reusable catalyst for the oxidation of tetralin to 1-tetralone using a combination of trimethylacetaldehyde and molecular oxygen (14.5 psi) and at 25°C. At 45.5% conversion, tetralin was converted to 1-tetralone with 77.2% selectivity at room temperature and atmospheric pressure after 24 h. The catalyst recycles test and hot filtration experiment showed that oxidation proceeded through Ni(II) sites in LDH-[Ni-salen]. The catalysts were reused several times without losing their catalytic activity and selectivity. The present results may provide a convenient strategy for the preparation of 1-tetralone using layered double hydroxide-based heterogeneous catalyst at ambient temperature for industrial application in near future.
基金financially supported by the National Natural Science Foundation of China(No.52173055 and 21961132024)the Natural Science Foundation of Shanghai(No.19ZR1401100)+3 种基金the International Cooperation Fund of Science and Technology Commission of Shanghai Municipality(No.21130750100)the Innovation Program of Shanghai Municipal Education Commission(No.2017-01-07-00-03-E00024)the Fundamental Research Funds for the Central Universities(No.18D310109)the DHU Distinguished Young Professor Program(No.LZA2020001).
文摘Bimetallic compounds such as hydrotalcite-type layered double hydroxides(LDHs)are promising electrocatalysts owing to their unique electronic structures.However,their abilities toward nitrogen adsorption and reduction are undermined since the surface-mantled,electronegative-OH groups hinder the charge transfer between transition metal atoms and nitrogen molecules.Herein,a smart interfacing strategy is proposed to construct a coupled heterointerface between LDH and 2D g-C_(3)N_(4),which is proven by density functional theory(DFT)investigations to be favorable for nitrogen adsorption and ammonia desorption compared with neat LDH surface.The interfaced LDH and g-C_(3)N_(4) is further hybridized with a self-standing TiO_(2) nanofibrous membrane(NM)to maximize the interfacial effect owing to its high porosity and large surface area.Profited from the synergistic superiorities of the three components,the LDH@C_(3)N_(4)@TiO_(2) NM delivers superior ammonia yield(2.07×10^(−9) mol s^(−1) cm^(−2))and Faradaic efficiency(25.3%),making it a high-efficiency,noble-metal-free catalyst system toward electrocatalytic nitrogen reduction.
基金supported by the National Research Foundation of Korea (NRF-2022R1C1C1004171)supported by the National Science Foundation (Grant number ACI1548562)。
文摘Layered double hydroxides(LDHs) have attracted considerable attention as a cost effective alternative to the precious iridium-and ruthenium-based electrocatalysts for an oxygen evolution reaction(OER),a bottleneck of water electrolysis for sustainable hydrogen production.Despite their excellent OER performance,the structural and electronic properties of LDHs,particularly during the OER process,remain to be poorly understood.In this study,a series of LDH catalysts is investigated through in situ X-ray absorption fine structure analyses and density functional theory(DFT) calculations.Our experimental results reveal that the LDH catalyst with equal amounts of Ni and Fe(NF-LDH) exhibits the highest OER activity and catalytic life span when compared with its counterparts having equal amounts of Ni and Co(NC-LDH)and Ni only(Ni-LDH).The NF-LDH shows a markedly enhanced OER kinetics compared to the NC-LDH and the Ni-LDH,as proven by the lower overpotentials of 180,240,and 310 mV,respectively,and the Tafel slopes of 35.1,43.4,and 62.7 mV dec^(-1),respectively.The DFT calculations demonstrate that the lowest overpotential of the NF-LDH is associated with the active sites located at the edge planes of NF-LDH in contrast to those located at the basal planes of Ni-LDH and NC-LDH.The current study pinpoints the active sites on various LDHs and presents strategies for optimizing the OER performance of the LDH catalysts.
基金Project(21306041)supported by the National Natural Science Young Foundation of ChinaProject(21271071)supported by the National Natural Science Foundation of ChinaProject(15A076)supported by the Scientific Research Foundation of Hunan Provincial Education Department of China
文摘ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.
基金Project(21176263)supported by the National Natural Science Foundation of China
文摘Layered double Mg-Fe-CO3 hydroxide （Mg-Fe-LDH） with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg-Fe-CLDH was obtained by heating Mg-Fe-LDH at 500 ℃ for 6 h. The as prepared Mg-Fe-LDH and calcined Mg-Fe-CLDH were used for removal of glutamic acid （Glu） from aqueous solution, respectively. Batch studies were carried out to address various experimental parameters such as contact time, pH, initial glutamic acid （Glu） concentration, co-existing anions and temperature. Glu was removed effectively （99.9%） under the optimized experimental conditions with Mg-Fe-CLDH. The adsorption kinetics follows the Ho’s pseudo second-order model. Isotherms for adsorption with Mg-Fe-CLDH at different solution temperatures were well described using the Langmuir model with a good correlation coefficient. The intraparticle diffusion model fitted the data well, which suggests that the intraparticle diffusion is not only the rate-limiting step.
基金Projects(21176263,21175155)supported by the National Natural Science Foundation of China
文摘Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773 K for 6 h. Removal of vanadate anion （ 3-4VO ） from aqueous solution on CLDH2 was studied. Batch studies were carried out to address various experimental parameters such as Mg/Al molar ratio, adsorbent dosage, initial concentration of solution, contact time and temperature. Vanadate was removed effectively at the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-first-order model. Isotherms for adsorption vanadate by CLDH2 at different solution temperatures were well described using the Langmuir and Freundlich equations, and the isotherm parameters were calculated using linear regression analysis. The adsorption data fitted the langmuir model with good values of the correlation coefficient （R2〉0.999）. The negative value ofΔGΘand the positive value ofΔHΘindicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption suggests that the surface adsorption is the main process.
基金The Fundamental Research Funds for the Central Universities,the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXLX12-0105)the Analysis and Test Fund of Southeast University(No.201226)
文摘Colored layered double hydroxides （LDHs） can be synthesized by introducing colored cations such as Fe^3＋ and Cr^3 ＋, which call be used as thermal stabilizers for polyvinyl chloride （PVC）. The yellowish Mg/Fe and bluish Mg/Cr LDHs are prepared by the co-precipitation method. The results show that the MgsCr_ CO3 and Mg3Fe_ CO3 colored layered double hydroxides can stabilize PVC for more than 30 min under the thermal aging temperature of 180 ℃. The preparation can use cheap Mg（OH） 2 instead of MgCl2, which produces a much smaller amount of the by-product NH4Cl. It is known that NH4Cl is a cheap fertilizer that is difficult to sell; therefore, the preparation is much greener and more economic than the one using magnesium salt.
基金financial support from the National Key R&D Program of China (Grant Nos.: 2017YFA0206904, 2017YFA0206900, and 2016YFB0600901)the National Program on Key Basic Research Project (Grant No.: 2014CB239402)+6 种基金the National Natural Science Foundation of China (Grant Nos.: 51772305, 51572270, U1662118, 31671489, U1332205, and 21701131)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.: XDB17000000)the Royal Society Newton Advanced Fellowship (Grant No.: NA170422)the Young Elite Scientist Sponsorship Program by CAST (Grant No.: YESS20160137)the Youth Innovation Promotion Association of the CASthe Fund of Xi’an University of Science and Technology (Grant No.:2018QDJ014)funding support from the Energy Education Trust of New Zealand
文摘For many two-dimensional(2D)materials,low coordination edges and corner sites offer greatly enhanced catalytic performance compared to basal sites,motivating the search for new synthetic approaches towards ultrathin and ultrafine 2D nanomaterials with high specific surface areas.To date,the synthesis of catalysts that are both ultrathin(monolayer)and ultrafine(lateral size<10nm)has proven extremely challenging.Herein,using a facile ultrasonic exfoliation procedure,we describe the successful synthesis of ultrafine ZnCo-LDH nanosheets(denoted as ZnCo-UF)with a size^3.5 nm and thickness^0.5 nm.The single layer ZnCo-UF nanosheets possess an abundance of oxygen vacancies(Vo)and unsaturated coordination s让es,thereby affording outstanding electrocatalytic water oxidation performance.DFT calculations confirmed that Vo on the surface of ZnCo-UF enhanced H20 adsorption via increasing the electropositivity of the nanosheets.
基金financially supported by the National Natural Science Foundation of China(U1707603,21521005,21975013,21901017)the National Key Research and Development Program of China(2017YFA0206500,2018YFA0702000)+2 种基金Beijing Natural Science Foundation(2172042)PetroChina Innovation Foundationthe Fundamental Research Funds for the Central Universities。
文摘With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1],fuel cells[2]and water splitting devices[3].Electrocatalytic oxidation of water to O2(oxygen evolution reaction,OER)is a vital chemical process involved in energy storage and conversion from renewable sources in form of molecular fuels such as H2 via water electrolysis,which has attracted a great amount of research efforts in the past few years[4,5].Nowadays,RuO2 and IrO2 are widely used as typical excellent OER electrocatalysts.However,their high-cost and scarce nature restricts the broadly commercial application of those materials[6,7].Hence,there is an urgent demand to develop low cost,highly efficient,and superb stable OER catalysts.
基金supported by the National Natural Science Foundation of China(Nos.U146211821601011)+2 种基金the 973 Program(Grant No.2014CB932102)the Fundamental Research Funds for the Central Universities(buctrc201506PYCC1704)
文摘The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides（LDHs） and their derivatives（e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides） have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.
基金supported in part by the WPIMANA,Ministry of Education,Culture,Sports,Science and TechnologyCREST of the Japan Science and Technology Agency(JST)(Grant No.JPMJCR17N1)the support from JSPS KAKENNHI grant 15H02004 and 18H03869.
文摘Layered double hydroxides(LDHs)have attracted tremendous research interest in widely spreading applications.Most notably,transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen evolution reaction(OER)due to their layered structure combined with versatile com-positions.Furthermore,reducing the thickness of platelet LDH crystals to nanometer or even molecular scale via cleavage or delamination provides an important clue to enhance the activity.In this review,recent progresses on rational design of LDH nanosheets are reviewed,including direct synthesis via traditional coprecipitation,homogeneous precipitation,and newly developed topochemical oxidation as well as chemical exfoliation of parent LDH crystals.In addition,diverse strategies are introduced to modulate their electrochemical activity by tuning the composition of host metal cations and intercalated counter-anions,and incorporating dopants,cavi-ties,and single atoms.In particular,hybridizing LDHs with conductive components or in situ growing them on conductive substrates to produce freestanding electrodes can further enhance their intrinsic catalytic activity.A brief discussion on future research directions and prospects is also summarized.
