In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxide...In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxides/hydroxides composite(FeMg/CER)was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment.Characteristics of FeMg/CER were determined by techniques such as Fouriertransform infrared spectroscopy,scanning electron microscopy,and Xray diffraction.The results showed that FeMg/CER material had a high nitrate adsorption capacity of 200 mg NO_(3)^()·g^(1)with a fast equilibrium adsorption time of 30 min at pH 5.In addition,it had good durability of at least 10 times of regeneration,which could be applied to practical water and wastewater treatment.展开更多
High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that ...High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.展开更多
Novel and promising chloride ion batteries(CIBs)that can operate at room temperature have attracted great attentions,due to the sustainable chloride-containing resources and high theoretical energy density.To achieve ...Novel and promising chloride ion batteries(CIBs)that can operate at room temperature have attracted great attentions,due to the sustainable chloride-containing resources and high theoretical energy density.To achieve the superior electrochemical properties of CIBs,the structure design of electrode materials is essential.Herein,2D NiAl-layered double hydroxide(NiAl-LDH)nanoarrays derived from Al2O3 are in-situ grafted to graphene(G)by atomic layer deposition(ALD)and hydrothermal method.The achieved NiAl-LDH@G hybrids with 2D NiAl-LDH arrays grown perpendicularly on graphene surface,can efficiently prevent the stacking of LDHs and enlarge specific surface area to provide more active sites.The NiAl-LDH@G cathode exhibits a maximum discharge capacity of 223.3 mA h g^(-1)and an excellent reversible capacity of 107 mA h g^(-1)over 500 cycles at 100 mA g^(-1)with a high coulombic efficiency around 96%,whereas pure NiAl-LDH has a discharge capacity of only 48.8 mA h g^(-1)and a coulombic efficiency(CE)of about 78%.More importantly,the NiAl-LDH@G electrode has a stable voltage at 1.9 V and an outstanding discharge capacity of higher than 72 mA h g^(-1)after 120 days.Additionally,XRD,XPS,and EDS have been employed to unveil the electrochemical reaction and Cl-storage mechanism of the NiAlLDH@G cathode in CIBs.This work opens a facile and reasonable way for improving electrochemical performance at anion-type rechargeable batteries in terms of cathode material design and mechanism interpretation.展开更多
CoFe bimetallic hydroxides(CoFe BMHs)find wide applications as excellent catalysts in the field of water splitting.However,no study has systematically investigated the influence of the morphologies of CoFe BMHs on cat...CoFe bimetallic hydroxides(CoFe BMHs)find wide applications as excellent catalysts in the field of water splitting.However,no study has systematically investigated the influence of the morphologies of CoFe BMHs on catalyst performance.In this study,CoFe BMH nanoflowers(CoFe BMH NFs),CoFe BMH nanosheets(CoFe BMH NSHs),CoFe BMH nanorods(CoFe BMH NRs),and CoFe BMH nanospheres(CoFe BMH NSPs)were prepared on nickel foam via a hydrothermal method.CoFe BMH NSHs exhibited the most beneficial catalytic activity.At a current density of 100 mA·cm^(-2),its overpotential for oxygen evolution reaction(OER)was 282 mV,and the overall water splitting voltage was 2.05 V.The double-layer charging capacitance(Cdl)value of CoFe BMH NSHs was the largest in CoFe BMHs,which proves that CoFe BMH NSHs have the largest active area.Furthermore,the active site in the OER process was metal oxyhydroxide(MOOH)through in situ Raman characterization,and the generation of the active substance was an irreversible process.This work provides important insights into the design of catalyst morphologies and offers valuable guidelines for the enhancement of the performance of other catalysts.展开更多
Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.H...Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.Herein,we find that oxygen vacancies can significantly boost the capacity,electrochemical kinetics,and structure stability of LDHs.The corresponding structure-performance relationship and energy storage mechanism are elaborated through exhaustive in/ex-situ experimental characterizations and density functional theory(DFT)calculations.Specially,in-situ Raman and DFT calculations reveal that oxygen vacancies elevate orbital energy of O 2p and electron density of O atoms,thereby enhancing the orbital hybridization of O 2p with Ni/Co 3d.This facilitates electron transfer between O and adjacent Ni/Co atoms and improves the covalency of Ni–O and Co–O bonds,which activates Ni/Co atoms to release more capacity and stabilizes the Ov-NiCo-LDH structure.Moreover,the distribution of relaxation times(DRT)and molecular dynamics(MD)simulations disclose that the enhanced d-p orbital hybridization optimizes the electronic structure of Ov-NiCo-LDH,which distinctly reduces the diffusion energy barriers of Mg^(2+)and improves the charge transfer kinetics of Ov-NiCo-LDH.Consequently,the assembled Ov-NiCo-LDH//active carbon(AC)and Ov-NiCo-LDH//perylenediimide(PTCDI)AMIBs can both deliver high specific discharge capacity(182.7 and 59.4 mAh g^(−1)at 0.5 A g^(−1),respectively)and long-term cycling stability(85.4%and 89.0%of capacity retentions after 2500 and 2400 cycles at 1.0 A g^(−1),respectively).In addition,the practical prospects for Ov-NiCo-LDH-based AMIBs have been demonstrated in different application scenarios.This work not only provides an effective strategy for obtaining high-performance cathodes of AMIBs,but also fundamentally elucidates the inherent mechanisms.展开更多
Electrically driven water splitting is an efficient method for green hydrogen production;however,its practical application is substantially constrained by the kinetically sluggish anodic oxygen evolution reaction(OER)...Electrically driven water splitting is an efficient method for green hydrogen production;however,its practical application is substantially constrained by the kinetically sluggish anodic oxygen evolution reaction(OER).Ruthenium(Ru)and its oxides are widely recognized as highly active OER catalysts.Although Ru is significantly cheaper than iridium(Ir),further reducing its content remains desirable.Herein,atomically dispersed Ru is doped into iron-nickel layered double hydroxides(Ru-FeNi-LDH)to decrease the Ru usage.We found that the Ru doping limit is roughly 9 wt%,and the Ru doping content significantly alters the OER kinetics-note that the high Ru concentration remarkably damages the Ru-FeNi-LDH structure and leads to agglomeration formation.By optimizing the Ru doping content to 3.3 wt%,the Ru-FeNi-LDH presents a low overpotential of 230 mV to reach a current density of 10 mA cm^(-2) in 1 M KOH,which is far better than the reference FeNi-LDH(280 mV)and RuO_(2)(350 mV).In the overall water splitting test,the current density of 10 mA cm^(-2) can be reached at a low voltage of 1.52 V,with stable operation for 80 h.Interestingly,Ru and Fe form an asymmetric Ru-Fe dipole,which is likely doped together into the LDH because the content of Fe instead of Ni is dependent on Ru content in experimental results.The electron-deficient feature of the Ru-Fe dipole thus facilitates the OER process.This work demonstrates a dual-transition metal synergy,providing a design strategy for OER and related catalysts.展开更多
Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and c...Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and complex synthesis processes.In this work,platinum atoms were anchored onto nickel-iron layered double hydroxide/carbon nanotube(LDH/CNT)hybrid electrocatalysts by using a straightforward milling technique with K_(2)Pt Cl_(6)·6H_(2)O as the Pt source.By adjusting the Pt-to-Fe ratio to 1/2 and 1/10,excellent electrocatalysts—Pt_(1/6)-Ni_(2/3)Fe_(1/3)-LDH/CNT and Pt_(1/30)-Ni_(2/3)Fe_(1/3)-LDH/CNT—were achieved with superior performance in hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),outperforming the corresponding commercial Pt/C(20 wt%)and Ru O_(2)electrocatalysts.The enhanced electrochemical performance is attributed to the modification of Pt's electronic structure,which exhibits electron-rich states for HER and electrondeficient states for OER,significantly boosting Pt's electrochemical activity.Furthermore,the simple milling technology for controlling Pt loading offers a promising approach for scaling up the production of electrocatalysts.展开更多
Malignant obstruction makes gallbladder cancer have a high mortality rate.Nickel-titanium alloy(nitinol)stents are commonly used as a local intervention to maximize patient survival time,but the stents lack antitumor ...Malignant obstruction makes gallbladder cancer have a high mortality rate.Nickel-titanium alloy(nitinol)stents are commonly used as a local intervention to maximize patient survival time,but the stents lack antitumor and antibacterial capacity and are vulnerable to secondary obstruction.Arsenic-based drugs show good therapeutic promise against gallbladder cancer.To meet clinical needs.the layered double hydroxides(LDHs)film is constructed on the nitinol,whose arsenite loading amounts rose by 60%after simple heat treatment compared with the conventional anion-exchange strategy.In addition,calcination promotes the dissolution of nickel ions from the LDHs lattice,resulting in a powerful synergistic killing effect on tumor cells together with the released arsenic.More importantly,the calcined arsenic-loaded LDHs are sensitive to the acidic microenvironment of tumor tissues,which presents a much lower arsenic and nickel release amount in the normal tissues,guaranteeing its biosafety.Meanwhile,the vertically sharp LDHs nanosheets can synergize with arsenic to achieve effective physical cleavage and chemical killing of adherent and planktonic bacteria.In short,we attempt to use arsenic drugs for local interventions and reasonably avoid their toxic side effects,which provides a new design idea for nitinol stents applied in the treatment of gallbladder cancer.展开更多
Designing efficient and long-lasting non-metal electrocatalysts is an urgent task for addressing the issue of kinetic hysteresis in electrochemical oxidation reactions.The bimetallic hydroxides,catalyzing the oxygen e...Designing efficient and long-lasting non-metal electrocatalysts is an urgent task for addressing the issue of kinetic hysteresis in electrochemical oxidation reactions.The bimetallic hydroxides,catalyzing the oxygen evolution reaction(OER),have significant research potential because hydroxide reconstruction to generate an active phase is a remarkable advantage.Herein,the complete reconstruction of ultrathin CoNi(OH)_(2) nanosheets was achieved by embedding Ag nanoparticles into the hydroxide to induce a spontaneous redox reaction(SRR),forming heterojunction Ag@CoNi(OH)_(2) for bifunctional hydrolysis.Theoretical calculations and in situ Raman and ex situ characterizations revealed that the inductive effect of the Ag cation redistributed the charge to promote phase transformation to highly activate Ag-modified hydroxides.The Co-Ni dual sites in Co/NiOOH serve as novel active sites for optimizing the intermediates,thereby weakening the barrier formed by OOH^*.Ag@CoNi(OH)_(2) required a potential of 1.55 V to drive water splitting at a current density of 10 mA cm^(-2),with nearly 98.6% Faraday efficiency.Through ion induction and triggering of electron regulation in the OER via the synergistic action of the heterogeneous interface and surface reconstruction,this strategic design can overcome the limited capacity of bimetallic hydroxides and bridge the gap between the basic theory and industrialization of water decomposition.展开更多
Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional...Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional structure andexhibit great potential as cathodes for multi-ion intercalation.However,theinsufficient active sites of LDHs result in low capacities in the discharging process.Interestingly,the LDHs after the deprotonation process exhibit favorable electrochemicalperformance of multi-cation intercalation.The deprotonation process ofLDHs has been widely found in the oxygen evolution reaction and energy storagefield,where LDHs lose H in laminates and converts to deprotonatedγ-phaseMOOHs(MOOs).Herein,we take a comprehensive overview of the dynamicsstructure transformation of the deprotonation process of LDHs.Furthermore,thedevelopment of advanced aqueous battery cathode and metal battery anode basedon deprotonated LDHs for energy storage is explored and summarized.Finally,theperspective of deprotonated LDHs in the energy storage field is discussed.展开更多
The dynamic surface self-reconstruction behavior in local structure correlates with oxygen evolution reaction(OER)performance,which has become an effective strategy for constructing the catalytic active phase.However,...The dynamic surface self-reconstruction behavior in local structure correlates with oxygen evolution reaction(OER)performance,which has become an effective strategy for constructing the catalytic active phase.However,it remains a challenge to understand the mechanisms of reconstruction and to accomplish it fast and deeply.Here,we reported a photo-promoted rapid reconstruction(PRR)process on Ag nanoparticle-loaded amorphous Ni-Fe hydroxide nanosheets on carbon cloth for enhanced OER.The photogenerated holes generated by Ag in conjunction with the anodic potential contributed to a thorough reconstruction of the amorphous substrate.The valence state of unsaturated coordinated Fe atoms,which serve as active sites,is significantly increased,while the corresponding crystalline substrate shows little change.The different structural evolutions of amorphous and crystalline substrates during reconstruction lead to diverse pathways of OER.This PRR utilizing loaded noble metal nanoparticles can accelerate the generation of active species in the substrate and increase the electrical conductivity,which provides a new inspiration to develop efficient catalysts via reconstruction strategies.展开更多
The detrimental“shuttle effect”of lithium polysulfides(LiPSs)together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur(Li-S)batteries from commercial success.Here,we first ...The detrimental“shuttle effect”of lithium polysulfides(LiPSs)together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur(Li-S)batteries from commercial success.Here,we first propose the implementability of layered rare-earth hydroxides(LREHs)in Li-S batteries to optimize electrochemical performance.In this work,a two-dimensional(2D)rare-earth-based composite constructed by the layered gadolinium hydroxy chloride[Gd_(2)(OH)_(5)(H_(2)O)_(n)]Cl nanoplates(LGdH NPs)and graphene oxide(GO)was designed as a sulfur immobilizer for Li-S batteries.Combining the experimental results and density functional theory(DFT)calculations,it is revealed that the LGdH@GO composite not only provides a strong anchoring of the intermediates during cycling,but also acts as an effective catalyst to accelerate the liquid-solid conversion of polysulfides.The Li-S batteries assembled by LGdH@GO modified separators delivered a superior rate performance with a specific capacity of 605.34 mAh/g at 5 C,as well as excellent cycle stability with a decay rate of 0.087%over 500 cycles at 2 C.This study provided a deep understanding of the mechanism to suppress the“shuttle effect”by the LREHs,and a guide to design effective functional interlayers for high-performance Li-S batteries with excellent electrocatalytic activity.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
Layered rare-earth hydroxides(LREHs) draw wide research interest because of their peculiar crystal structure,rich interlayer chemistry and abundant functionality of the RE element,but are limited to the two categories...Layered rare-earth hydroxides(LREHs) draw wide research interest because of their peculiar crystal structure,rich interlayer chemistry and abundant functionality of the RE element,but are limited to the two categories of RE_(2)(OH)_(5)A·nH_(2)O(A:typical of Cl^(-)or NO_(3)^(-)) and RE_(2)(OH)_(4)SO_(4)·nH_(2)O.On the other hand,rare-earth oxysulfates(RE_(2)O_(2)SO_(4)) have attracted attention due to their properties of large-capacity oxygen storage,low-temperature magnetism and luminescence,but their preparation procedure mostly involves toxic SO_(x) gases and/or complicated procedures.In this work,RE_(2)(OH)_(2)CO_(3)SO_(4)·nH_(2)O as a new family of LREHs(RE=Gd-Lu lanthanides and Y) were produced via hydrothermal reaction,from which phase-pure RE_(2)O_(2)SO_(4) was derived via subsequent annealing at 800℃ in air without the involvement of SO_(x),The compounds were thoroughly characterized to reveal the intrinsic influence of lanthanide contraction(RE^(3+) radius) on crystal structure,thermal behavior(dehydroxylation/decarbonation/desulfurization),vibrational property and crystallite morphology.Through analyzing the photoluminescence of Eu^(3+) and Sm^(3+)in the Gd_(2)O_(2)SO_(4) typical host it is found that the 617 nm(Eu^(3+),λ_(ex)=275 nm) and 608 nm(Sm^(3+),λ_(ex)=407 nm) main emissions can retain as high as ^(7)9.6% and 85.5%of their room-temperature intensities at 423 K,with activation energies of ~0.19 and 0.21 eV for thermal quenching,respectively.Application also indicates that both the phosphors have the potential for optical temperature sensing via the fluorescence intensity ratio(FIR) technology,whose maximum relative sensitivity reaches -2.70%/K for Eu^(3+)and 1.73%/K for Sm^(3+) at 298 K.展开更多
Delivering high areal capacitance(CA)at high rates is crucial but challenging for flexible supercapacitors.CA is the product of areal loading mass(MA)and gravimetric capacitance(CW).Finding and understanding the balan...Delivering high areal capacitance(CA)at high rates is crucial but challenging for flexible supercapacitors.CA is the product of areal loading mass(MA)and gravimetric capacitance(CW).Finding and understanding the balance between MA and CW of supercapacitor materials is significant for designing high-CA electrodes.Herein,we have systematically studied the correlation between MA and CW of the nanosheet arrays of NiCo-layered double hydroxide(NiCo-LDH),which were electrodeposited on carbon cloth with different heights to adjust the MA,accompanied by the interlayer distance regulation to improve the CW.The optimal CW performance is achieved at the best charge transfer kinetics for each of MA series.The NiCo-LDH electrode with the suitable MA(2.58 mg cm^(-2))and the relatively high CW(1918 F g^(-1) at 5 A g^(-1) and 400 F g^(-1) at 150 A g^(-1))present a high CA of 4948 mF cm^(-2) at 12.9 mA cm^(-2) and a record-high 1032 mF cm^(-2) among LDHs-based flexible electrodes at an ultrahigh current density of 387 mA cm^(-2).The corresponding flexible supercapacitor coupled with activated carbon delivers a high energy density of 0.28 mWh cm^(-2) at an ultrahigh power density of 712 mW cm^(-2),showing great potential applications.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
Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological b...Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.展开更多
Precipitation is often used for the preparation of La(OH)_(3)with precipitants of liquid alkali and ammonia.To solve the problems of high cost and wastewater pollution caused by common precipitants,the active MgO synt...Precipitation is often used for the preparation of La(OH)_(3)with precipitants of liquid alkali and ammonia.To solve the problems of high cost and wastewater pollution caused by common precipitants,the active MgO synthesized by pyrolysis was used as the precipitant to prepare La(OH)_(3).The species distribution of LaCl_(3)and LaCl_(3)-MgCl_(2)mixed system solution was calculated,and the kinetic analysis of the precipi-tation process was carried out to confirm the key factors influencing the precipitation of La(OH)_(3).The results show that La(OH)_(3)with D_(50)of 5.57μm,a specific surface area of 25.70 m^(2)/g,a rod-like shape,and MgO content of 0.044 wt%,was successfully prepared by adding active MgO.The precipitation ratio of La reaches 99.92%.The La(OH)_(3)precipitation is controlled by the diffusion process.The activity of MgO has a significant influence on MgO content in the precipitate.The preparation of La(OH)_(3)by active MgO provides a potential way for an eco-friendly preparation method of rare earth.展开更多
Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demo...Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
基金Vietnam National University-Ho Chi Minh City under grant number A2020-16-01.
文摘In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxides/hydroxides composite(FeMg/CER)was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment.Characteristics of FeMg/CER were determined by techniques such as Fouriertransform infrared spectroscopy,scanning electron microscopy,and Xray diffraction.The results showed that FeMg/CER material had a high nitrate adsorption capacity of 200 mg NO_(3)^()·g^(1)with a fast equilibrium adsorption time of 30 min at pH 5.In addition,it had good durability of at least 10 times of regeneration,which could be applied to practical water and wastewater treatment.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(No.52021004)the Funds for Chongqing Talents Plan(No.CQYC2021059563)+1 种基金the Fundamental Research Funds for the Central Universities(No.2021CDJQY-027)the National Natural Science Foundation of China(No.52206089).
文摘High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.22278101,22068010,22168016,and 52365044)the Natural Science Foundation of Hainan Province(Grant Nos.2019RC142 and 519QN176)the Finance Science and Technology Project of Hainan Province(Grant No.ZDYF2020009).
文摘Novel and promising chloride ion batteries(CIBs)that can operate at room temperature have attracted great attentions,due to the sustainable chloride-containing resources and high theoretical energy density.To achieve the superior electrochemical properties of CIBs,the structure design of electrode materials is essential.Herein,2D NiAl-layered double hydroxide(NiAl-LDH)nanoarrays derived from Al2O3 are in-situ grafted to graphene(G)by atomic layer deposition(ALD)and hydrothermal method.The achieved NiAl-LDH@G hybrids with 2D NiAl-LDH arrays grown perpendicularly on graphene surface,can efficiently prevent the stacking of LDHs and enlarge specific surface area to provide more active sites.The NiAl-LDH@G cathode exhibits a maximum discharge capacity of 223.3 mA h g^(-1)and an excellent reversible capacity of 107 mA h g^(-1)over 500 cycles at 100 mA g^(-1)with a high coulombic efficiency around 96%,whereas pure NiAl-LDH has a discharge capacity of only 48.8 mA h g^(-1)and a coulombic efficiency(CE)of about 78%.More importantly,the NiAl-LDH@G electrode has a stable voltage at 1.9 V and an outstanding discharge capacity of higher than 72 mA h g^(-1)after 120 days.Additionally,XRD,XPS,and EDS have been employed to unveil the electrochemical reaction and Cl-storage mechanism of the NiAlLDH@G cathode in CIBs.This work opens a facile and reasonable way for improving electrochemical performance at anion-type rechargeable batteries in terms of cathode material design and mechanism interpretation.
基金supported by the National Science Fund for Distinguished Young Scholars(No.52025041)the National Natural Science Foundation of China(Nos.52474319,52250091,U2341267,and 52450003)+1 种基金the Fundamental Research Funds for the Central Universities(No.FRF-TP-20-02C2)supported by the Interdisciplinary Research Project for Young Teachers of USTB,China(Fundamental Research Funds for the Central Universities)(No.FRF-IDRY-GD23-003).
文摘CoFe bimetallic hydroxides(CoFe BMHs)find wide applications as excellent catalysts in the field of water splitting.However,no study has systematically investigated the influence of the morphologies of CoFe BMHs on catalyst performance.In this study,CoFe BMH nanoflowers(CoFe BMH NFs),CoFe BMH nanosheets(CoFe BMH NSHs),CoFe BMH nanorods(CoFe BMH NRs),and CoFe BMH nanospheres(CoFe BMH NSPs)were prepared on nickel foam via a hydrothermal method.CoFe BMH NSHs exhibited the most beneficial catalytic activity.At a current density of 100 mA·cm^(-2),its overpotential for oxygen evolution reaction(OER)was 282 mV,and the overall water splitting voltage was 2.05 V.The double-layer charging capacitance(Cdl)value of CoFe BMH NSHs was the largest in CoFe BMHs,which proves that CoFe BMH NSHs have the largest active area.Furthermore,the active site in the OER process was metal oxyhydroxide(MOOH)through in situ Raman characterization,and the generation of the active substance was an irreversible process.This work provides important insights into the design of catalyst morphologies and offers valuable guidelines for the enhancement of the performance of other catalysts.
基金financial support of the National Natural Science Foundation of China (22379063)
文摘Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.Herein,we find that oxygen vacancies can significantly boost the capacity,electrochemical kinetics,and structure stability of LDHs.The corresponding structure-performance relationship and energy storage mechanism are elaborated through exhaustive in/ex-situ experimental characterizations and density functional theory(DFT)calculations.Specially,in-situ Raman and DFT calculations reveal that oxygen vacancies elevate orbital energy of O 2p and electron density of O atoms,thereby enhancing the orbital hybridization of O 2p with Ni/Co 3d.This facilitates electron transfer between O and adjacent Ni/Co atoms and improves the covalency of Ni–O and Co–O bonds,which activates Ni/Co atoms to release more capacity and stabilizes the Ov-NiCo-LDH structure.Moreover,the distribution of relaxation times(DRT)and molecular dynamics(MD)simulations disclose that the enhanced d-p orbital hybridization optimizes the electronic structure of Ov-NiCo-LDH,which distinctly reduces the diffusion energy barriers of Mg^(2+)and improves the charge transfer kinetics of Ov-NiCo-LDH.Consequently,the assembled Ov-NiCo-LDH//active carbon(AC)and Ov-NiCo-LDH//perylenediimide(PTCDI)AMIBs can both deliver high specific discharge capacity(182.7 and 59.4 mAh g^(−1)at 0.5 A g^(−1),respectively)and long-term cycling stability(85.4%and 89.0%of capacity retentions after 2500 and 2400 cycles at 1.0 A g^(−1),respectively).In addition,the practical prospects for Ov-NiCo-LDH-based AMIBs have been demonstrated in different application scenarios.This work not only provides an effective strategy for obtaining high-performance cathodes of AMIBs,but also fundamentally elucidates the inherent mechanisms.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2022B1515120079)Tertiary Education Scientific research project of Guangzhou Municipal Education Bureau(2024312194)+1 种基金the Science and Technology Projects in Guangzhou(2024A03J0308)the Outstanding Youth Project of Natural Science Foundation of Guangdong Province(2022B1515020020).
文摘Electrically driven water splitting is an efficient method for green hydrogen production;however,its practical application is substantially constrained by the kinetically sluggish anodic oxygen evolution reaction(OER).Ruthenium(Ru)and its oxides are widely recognized as highly active OER catalysts.Although Ru is significantly cheaper than iridium(Ir),further reducing its content remains desirable.Herein,atomically dispersed Ru is doped into iron-nickel layered double hydroxides(Ru-FeNi-LDH)to decrease the Ru usage.We found that the Ru doping limit is roughly 9 wt%,and the Ru doping content significantly alters the OER kinetics-note that the high Ru concentration remarkably damages the Ru-FeNi-LDH structure and leads to agglomeration formation.By optimizing the Ru doping content to 3.3 wt%,the Ru-FeNi-LDH presents a low overpotential of 230 mV to reach a current density of 10 mA cm^(-2) in 1 M KOH,which is far better than the reference FeNi-LDH(280 mV)and RuO_(2)(350 mV).In the overall water splitting test,the current density of 10 mA cm^(-2) can be reached at a low voltage of 1.52 V,with stable operation for 80 h.Interestingly,Ru and Fe form an asymmetric Ru-Fe dipole,which is likely doped together into the LDH because the content of Fe instead of Ni is dependent on Ru content in experimental results.The electron-deficient feature of the Ru-Fe dipole thus facilitates the OER process.This work demonstrates a dual-transition metal synergy,providing a design strategy for OER and related catalysts.
基金supported by the Natural Science Foundation of Henan(242300421230)the Young Teacher Fundamental Research Cultivation Program of Zhengzhou University(JC23557030)the National Natural Science Foundation of China(U21A20281 and 22208322)。
文摘Noble metal-loaded layered hydroxides exhibit high efficiency in electrocatalyzing water splitting.However,their widespread use as bifunctional electrocatalysts is hindered by low metal loading,inefficient yield,and complex synthesis processes.In this work,platinum atoms were anchored onto nickel-iron layered double hydroxide/carbon nanotube(LDH/CNT)hybrid electrocatalysts by using a straightforward milling technique with K_(2)Pt Cl_(6)·6H_(2)O as the Pt source.By adjusting the Pt-to-Fe ratio to 1/2 and 1/10,excellent electrocatalysts—Pt_(1/6)-Ni_(2/3)Fe_(1/3)-LDH/CNT and Pt_(1/30)-Ni_(2/3)Fe_(1/3)-LDH/CNT—were achieved with superior performance in hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),outperforming the corresponding commercial Pt/C(20 wt%)and Ru O_(2)electrocatalysts.The enhanced electrochemical performance is attributed to the modification of Pt's electronic structure,which exhibits electron-rich states for HER and electrondeficient states for OER,significantly boosting Pt's electrochemical activity.Furthermore,the simple milling technology for controlling Pt loading offers a promising approach for scaling up the production of electrocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.31971249 and 51901239)the Science and Technology Commission of Shanghai Municipality(Nos.19JC1415500 and 20S31903300)。
文摘Malignant obstruction makes gallbladder cancer have a high mortality rate.Nickel-titanium alloy(nitinol)stents are commonly used as a local intervention to maximize patient survival time,but the stents lack antitumor and antibacterial capacity and are vulnerable to secondary obstruction.Arsenic-based drugs show good therapeutic promise against gallbladder cancer.To meet clinical needs.the layered double hydroxides(LDHs)film is constructed on the nitinol,whose arsenite loading amounts rose by 60%after simple heat treatment compared with the conventional anion-exchange strategy.In addition,calcination promotes the dissolution of nickel ions from the LDHs lattice,resulting in a powerful synergistic killing effect on tumor cells together with the released arsenic.More importantly,the calcined arsenic-loaded LDHs are sensitive to the acidic microenvironment of tumor tissues,which presents a much lower arsenic and nickel release amount in the normal tissues,guaranteeing its biosafety.Meanwhile,the vertically sharp LDHs nanosheets can synergize with arsenic to achieve effective physical cleavage and chemical killing of adherent and planktonic bacteria.In short,we attempt to use arsenic drugs for local interventions and reasonably avoid their toxic side effects,which provides a new design idea for nitinol stents applied in the treatment of gallbladder cancer.
基金supported by the Inner Mongolia R&D Program Plan(2021ZD0042,2021EEDSCXSFQZD006)the National Natural Science Foundation of China(21902123)the Natural Science Basic Research Program of Shaanxi(2023-JC-ZD-22)。
文摘Designing efficient and long-lasting non-metal electrocatalysts is an urgent task for addressing the issue of kinetic hysteresis in electrochemical oxidation reactions.The bimetallic hydroxides,catalyzing the oxygen evolution reaction(OER),have significant research potential because hydroxide reconstruction to generate an active phase is a remarkable advantage.Herein,the complete reconstruction of ultrathin CoNi(OH)_(2) nanosheets was achieved by embedding Ag nanoparticles into the hydroxide to induce a spontaneous redox reaction(SRR),forming heterojunction Ag@CoNi(OH)_(2) for bifunctional hydrolysis.Theoretical calculations and in situ Raman and ex situ characterizations revealed that the inductive effect of the Ag cation redistributed the charge to promote phase transformation to highly activate Ag-modified hydroxides.The Co-Ni dual sites in Co/NiOOH serve as novel active sites for optimizing the intermediates,thereby weakening the barrier formed by OOH^*.Ag@CoNi(OH)_(2) required a potential of 1.55 V to drive water splitting at a current density of 10 mA cm^(-2),with nearly 98.6% Faraday efficiency.Through ion induction and triggering of electron regulation in the OER via the synergistic action of the heterogeneous interface and surface reconstruction,this strategic design can overcome the limited capacity of bimetallic hydroxides and bridge the gap between the basic theory and industrialization of water decomposition.
基金support from the National Natural Science Foundation of China(22090031,22090030,22288102),Qinghai Salt Lake Industry Group Co.,Ltd.
文摘Aqueous rechargeable batteries using abundant multi-ion cations have receivedincreasing attention in the energy storage field for their high safety and low cost.Layered double hydroxides(LDHs)possess a two-dimensional structure andexhibit great potential as cathodes for multi-ion intercalation.However,theinsufficient active sites of LDHs result in low capacities in the discharging process.Interestingly,the LDHs after the deprotonation process exhibit favorable electrochemicalperformance of multi-cation intercalation.The deprotonation process ofLDHs has been widely found in the oxygen evolution reaction and energy storagefield,where LDHs lose H in laminates and converts to deprotonatedγ-phaseMOOHs(MOOs).Herein,we take a comprehensive overview of the dynamicsstructure transformation of the deprotonation process of LDHs.Furthermore,thedevelopment of advanced aqueous battery cathode and metal battery anode basedon deprotonated LDHs for energy storage is explored and summarized.Finally,theperspective of deprotonated LDHs in the energy storage field is discussed.
基金This work was supported by the National Natural Science Foundation of China(52073008,52272181)the China Postdoctoral Science Foundation(2023T160036).
文摘The dynamic surface self-reconstruction behavior in local structure correlates with oxygen evolution reaction(OER)performance,which has become an effective strategy for constructing the catalytic active phase.However,it remains a challenge to understand the mechanisms of reconstruction and to accomplish it fast and deeply.Here,we reported a photo-promoted rapid reconstruction(PRR)process on Ag nanoparticle-loaded amorphous Ni-Fe hydroxide nanosheets on carbon cloth for enhanced OER.The photogenerated holes generated by Ag in conjunction with the anodic potential contributed to a thorough reconstruction of the amorphous substrate.The valence state of unsaturated coordinated Fe atoms,which serve as active sites,is significantly increased,while the corresponding crystalline substrate shows little change.The different structural evolutions of amorphous and crystalline substrates during reconstruction lead to diverse pathways of OER.This PRR utilizing loaded noble metal nanoparticles can accelerate the generation of active species in the substrate and increase the electrical conductivity,which provides a new inspiration to develop efficient catalysts via reconstruction strategies.
基金supported by National Science Foundation for Youths of China(Nos.22209184 and 22109163)。
文摘The detrimental“shuttle effect”of lithium polysulfides(LiPSs)together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur(Li-S)batteries from commercial success.Here,we first propose the implementability of layered rare-earth hydroxides(LREHs)in Li-S batteries to optimize electrochemical performance.In this work,a two-dimensional(2D)rare-earth-based composite constructed by the layered gadolinium hydroxy chloride[Gd_(2)(OH)_(5)(H_(2)O)_(n)]Cl nanoplates(LGdH NPs)and graphene oxide(GO)was designed as a sulfur immobilizer for Li-S batteries.Combining the experimental results and density functional theory(DFT)calculations,it is revealed that the LGdH@GO composite not only provides a strong anchoring of the intermediates during cycling,but also acts as an effective catalyst to accelerate the liquid-solid conversion of polysulfides.The Li-S batteries assembled by LGdH@GO modified separators delivered a superior rate performance with a specific capacity of 605.34 mAh/g at 5 C,as well as excellent cycle stability with a decay rate of 0.087%over 500 cycles at 2 C.This study provided a deep understanding of the mechanism to suppress the“shuttle effect”by the LREHs,and a guide to design effective functional interlayers for high-performance Li-S batteries with excellent electrocatalytic activity.
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.
基金supported in part by the National Natural Science Foundation of China (52172112,51972047)。
文摘Layered rare-earth hydroxides(LREHs) draw wide research interest because of their peculiar crystal structure,rich interlayer chemistry and abundant functionality of the RE element,but are limited to the two categories of RE_(2)(OH)_(5)A·nH_(2)O(A:typical of Cl^(-)or NO_(3)^(-)) and RE_(2)(OH)_(4)SO_(4)·nH_(2)O.On the other hand,rare-earth oxysulfates(RE_(2)O_(2)SO_(4)) have attracted attention due to their properties of large-capacity oxygen storage,low-temperature magnetism and luminescence,but their preparation procedure mostly involves toxic SO_(x) gases and/or complicated procedures.In this work,RE_(2)(OH)_(2)CO_(3)SO_(4)·nH_(2)O as a new family of LREHs(RE=Gd-Lu lanthanides and Y) were produced via hydrothermal reaction,from which phase-pure RE_(2)O_(2)SO_(4) was derived via subsequent annealing at 800℃ in air without the involvement of SO_(x),The compounds were thoroughly characterized to reveal the intrinsic influence of lanthanide contraction(RE^(3+) radius) on crystal structure,thermal behavior(dehydroxylation/decarbonation/desulfurization),vibrational property and crystallite morphology.Through analyzing the photoluminescence of Eu^(3+) and Sm^(3+)in the Gd_(2)O_(2)SO_(4) typical host it is found that the 617 nm(Eu^(3+),λ_(ex)=275 nm) and 608 nm(Sm^(3+),λ_(ex)=407 nm) main emissions can retain as high as ^(7)9.6% and 85.5%of their room-temperature intensities at 423 K,with activation energies of ~0.19 and 0.21 eV for thermal quenching,respectively.Application also indicates that both the phosphors have the potential for optical temperature sensing via the fluorescence intensity ratio(FIR) technology,whose maximum relative sensitivity reaches -2.70%/K for Eu^(3+)and 1.73%/K for Sm^(3+) at 298 K.
基金supported by the National Key Research and Development Program of China(Nos.2021YFA1500900,2018YFA0209103)the National Natural Science Foundation of China(Nos.21832003,52071174,21972061,22369020)+1 种基金the Natural Science Foundation of Jiangsu Province Major Project(No.BK20212005)the Project funded by China Postdoctoral Science Foundation(No.2023M732352).
文摘Delivering high areal capacitance(CA)at high rates is crucial but challenging for flexible supercapacitors.CA is the product of areal loading mass(MA)and gravimetric capacitance(CW).Finding and understanding the balance between MA and CW of supercapacitor materials is significant for designing high-CA electrodes.Herein,we have systematically studied the correlation between MA and CW of the nanosheet arrays of NiCo-layered double hydroxide(NiCo-LDH),which were electrodeposited on carbon cloth with different heights to adjust the MA,accompanied by the interlayer distance regulation to improve the CW.The optimal CW performance is achieved at the best charge transfer kinetics for each of MA series.The NiCo-LDH electrode with the suitable MA(2.58 mg cm^(-2))and the relatively high CW(1918 F g^(-1) at 5 A g^(-1) and 400 F g^(-1) at 150 A g^(-1))present a high CA of 4948 mF cm^(-2) at 12.9 mA cm^(-2) and a record-high 1032 mF cm^(-2) among LDHs-based flexible electrodes at an ultrahigh current density of 387 mA cm^(-2).The corresponding flexible supercapacitor coupled with activated carbon delivers a high energy density of 0.28 mWh cm^(-2) at an ultrahigh power density of 712 mW cm^(-2),showing great potential applications.
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support from the National Natural Science Foundation of China(grant number 52075544)Innovation Funds of Jihua Laboratory(X220971UZ230)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515110649)Funds from Research Platforms of Guangdong Higher Education Institutes(2022ZDJS038).
文摘Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.
基金the National Key Research and Development Program of China(2022YFB3504503)the National Natural Science Foundation of China(52274355)the Gansu Province Science and Technology Major Special Project,China(22ZD6GD061).
文摘Precipitation is often used for the preparation of La(OH)_(3)with precipitants of liquid alkali and ammonia.To solve the problems of high cost and wastewater pollution caused by common precipitants,the active MgO synthesized by pyrolysis was used as the precipitant to prepare La(OH)_(3).The species distribution of LaCl_(3)and LaCl_(3)-MgCl_(2)mixed system solution was calculated,and the kinetic analysis of the precipi-tation process was carried out to confirm the key factors influencing the precipitation of La(OH)_(3).The results show that La(OH)_(3)with D_(50)of 5.57μm,a specific surface area of 25.70 m^(2)/g,a rod-like shape,and MgO content of 0.044 wt%,was successfully prepared by adding active MgO.The precipitation ratio of La reaches 99.92%.The La(OH)_(3)precipitation is controlled by the diffusion process.The activity of MgO has a significant influence on MgO content in the precipitate.The preparation of La(OH)_(3)by active MgO provides a potential way for an eco-friendly preparation method of rare earth.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(No.12034002)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities,No.FRF-IDRY-23-033)。
文摘Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
