Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to a...Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to all reactions,making it essential to understand the electrochemistry of selected TMDs.Tungsten diselenide(WSe_(2))is reactive in gas evolution processes,similar to molybdenum,yet has received limited attention.This work explores how different exfoliation powers affect WSe_(2)structural configurations and their impact on catalytic performance in hydrogen evolution,oxygen evolution,and capacitive behaviour.The study investigates the structural properties of WSe_(2)nanosheets in both liquid(dispersion)and solid(electrode)phases.Low exfoliation power(90.4 W)contributes to well-defined WSe_(2),while higher power(814 W)leads to an increased number of selenium vacancies.These modifications influence key properties such as thickness,band gaps(1.518 to 1.578 eV),exfoliation yield(0.27 to 0.12 mg mL^(-1)),and oxide content(44.3%to 53.9%),resulting in distinct electrochemical behaviours in different electrolytes.WSe_(2)nanosheets exfoliated at higher power exhibit reduced activity in the hydrogen evolution reaction(HER)due to the loss of W–Se bonds and the formation of an amorphous structure,but they show enhanced oxygen evolution reaction(OER)performance,particularly in alkaline media.Additionally,a higher concentration of selenium vacancies improves capacitive performance in acidic conditions due to proton contributions but are less favourable in neutral and basic electrolytes.This study highlights the importance of exfoliation power in tuning the structural properties of WSe_(2)for specific electrochemical applications,advancing the understanding of its synthesis and performance.展开更多
The preparation of dispersible MFI-type zeolite nanoparticles with open micropores is challenging.Herein,a rapid and effective ultrasound-assisted liquid-phase exfoliation method along with a freezedrying process for ...The preparation of dispersible MFI-type zeolite nanoparticles with open micropores is challenging.Herein,a rapid and effective ultrasound-assisted liquid-phase exfoliation method along with a freezedrying process for redispersion of calcined silicalite-1(S-1)zeolite nanoparticle aggregates using 3-aminopropanol as an exfoliating agent is demonstrated.The exfoliation of S-1 zeolite nanoparticles is characterized by X-ray diffraction,scanning electron microscopy and DLS particle size analysis.The effects of drying methods of as-synthesized zeolite nanoparticle suspension,zeolite contents in frozen nanoparticle suspension,exfoliating agent concentrations,and zeolite doses in ultrasonic suspension on exfoliation efficiency are systematically investigated.It is found that the S-1 zeolite nanoparticle(~70 nm)achieves a yield up to 95%through a 30 min ultrasonic exfoliation in a 3-aminopropanol solution along with a freeze-drying process.The proposed exfoliation mechanism involves two primary stages:vip molecule insertion followed by water expansion,both substantially enhanced by tip sonication.This work offers a comprehensive understanding of the exfoliation process,provides valuable insights into the dispersion of sintered zeolite nanoparticles.展开更多
Background:Enzyme fragility remains a major challenge in research and applications.Free enzymes are highly unstable,inactivated by heat,acid,alkali,or organic solvents,and often lose activity even under optimal storag...Background:Enzyme fragility remains a major challenge in research and applications.Free enzymes are highly unstable,inactivated by heat,acid,alkali,or organic solvents,and often lose activity even under optimal storage conditions.Limiting their use in cosmetics.Few commercial products combine acids and enzymes effectively.Objective:To investigate the physicochemical properties,in vitro exfoliation efficacy,and effects on facial skin parameters of a supramolecular acid-enzyme complex(SAE)composed of mandelic acid(MAN),betaine(BET),and composite enzymes(CE;papain and bromelain),thereby establishing a theoretical foundation for cosmetic applications.Methods:The supramolecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy and proton nuclear magnetic resonance(1H NMR)spectroscopy.Dissolution experiments were conducted to compare the solubility of SAE and CE in aqueous solutions.Enzymatic activity assays evaluated the stabilizing effect of supramolecular deep eutectic technology on enzymes.In vitro exfoliation tests assessed acid-enzyme synergy in keratin removal.A 4-week clinical trial evaluated the efficacy of a 2%SAE essence aqueous solution on facial skin parameters.Results:Dissolution experiments confirmed that supramolecular deep eutectic technology significantly improved enzyme solubility.Enzymatic activity tests demonstrated that this technology effectively preserved protease activity,substantially enhancing its practical applicability.Furthermore,in vitro exfoliation efficacy tests revealed that this technology strengthened the synergistic interaction between acids and enzymes and exhibited superior stratum corneum-removing capability of the SAE.In clinical evaluations of efficacy,after 7 days of using the essence containing SAE,the formulation significantly enhanced cheek gloss(+8.08%),while reducing comedones volume(-16.25%).after 28 days,significantly enhanced cheek hydration(+25.0%,SCH),gloss(+15.93%),and smoothness(−7.78%SEsm),while reducing TEWL(−6.86%),sebum(−15.54%),roughness(+16.24%SEr),and pore metrics(volume:−39.98%;count:−30.64%),and decreased comedones(blackheads:−70.33%;Whiteheads:−52.42%;all p<0.05).Conclusion:The supramolecular acid-enzyme complex demonstrates enhanced stability,improved solubility,and superior exfoliation efficacy compared to free enzymes.Clinical results further confirm its multifunctional benefits,including enhancing skin hydration,sebum regulation,barrier repair,pore refinement,and comedolytic effects.This study provides both theoretical and practical foundations for developing stable acid-enzyme combinations in dermatological applications.展开更多
Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It ...Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It exhibits negligible interlayer electronic coupling and significant excitonic behavior in the bulk state.Here we substantiate that NbOCl_(2) nanosheets can be exfoliated and effectively size-selected using controlled centrifugation techniques by the liquid phase exfoliation(LPE)method.Spectroscopic measurements displayed that the variations in dispersion were highly dependent on the nanosheet dimensions.The nanosheets seemed to be comparatively defect-free which will be further corroborated by high resolution transmission electron microscopy(HRTEM)and Raman analysis.The size selected nanosheets are unanticipated stable in isopropyl alcohol(IPA),possibly owing to the protective influence of a solvation shell.Additionally,the photothermal conversion response and photothermal stability of nanosized NbOCl_(2) were investigated.Our finding revealed that NbOCl_(2) possesses a robust photothermal agent property,boasting a photothermal conversion efficiency of more than 30%.This underscores its promising potential for various photothermal applications in different fields such as photothermal therapy and thermal energy conversion.展开更多
With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent p...With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent properties,such as distinct pleated structures in layers,adjustable direct bandgap,high carrier mobility,moderate on/off ratio,large specific surface area,and various interesting in-layer anisotropies.However,the realization of these excellent properties depends on the preparation of highquality 2 D BP sheets.Electrochemical exfoliation methods are typically performed under mild conditions,thus,these methods are convenient,controllable,and can produce high-quality 2 D BP sheets.This review summarizes research progress in BP sheets preparation through anodic,cathodic,and electrolyte exfoliation in recent years.Different exfoliating methods affect the quality of 2 D BP sheets.Moreover,possible exfoliating mechanisms and the potential applications of different exfoliating methods are summarized and discussed in detail.Lastly,the shortcomings of existing research on electrochemical exfoliation are presented,and suggestions and prospects for future research on the electrochemical exfoliation of 2 D BP are proposed.展开更多
The exfoliation corrosion （EFC） behavior of 7050-T6 aluminum alloy treated with various quench transfer time after solution heat treatment was investigated by standard EFC immersion tests, strength loss measurements...The exfoliation corrosion （EFC） behavior of 7050-T6 aluminum alloy treated with various quench transfer time after solution heat treatment was investigated by standard EFC immersion tests, strength loss measurements after EFC tests and electrochemical impedance spectroscope （EIS） technique. The results showed that EFC resistance of the alloy decreased with increasing quench transfer time. Backscattered electron scanning electron microscope （SEM） together with transmission electron microscope （TEM） observations revealed that the coverage ratio and microstructure of precipitates at grain boundary area are the most important factors which influence the EFC susceptibility of the alloy, while precipitate-free zone （PFZ） near grain boundary has no or only a minor effect on it. In addition, galvanostatic measurements of the alloy present a good correlation between EFC resistance and transients in potential. The cumulated number of transients in potential can be used to evaluate EFC resistance of the alloy.展开更多
Influence of dual retrogression and re-aging（dual-RRA） temper on microstructure,strength and exfoliation corrosion（EC） behavior of Al-Zn-Mg-Cu alloy was investigated by hardness measurements,tensile properties tes...Influence of dual retrogression and re-aging（dual-RRA） temper on microstructure,strength and exfoliation corrosion（EC） behavior of Al-Zn-Mg-Cu alloy was investigated by hardness measurements,tensile properties tests,exfoliation corrosion tests,transmission electron microscopy（TEM） and scanning electron microscopy（SEM） observation combined energy dispersive X-ray detector（EDX） analysis.Dual-RRA temper maintains the matrix precipitates（MPs） similar to RRA temper,meanwhile obtains coarser and sparser grain boundary precipitates（GBPs） as well as higher Cu and lower Zn content compared with T76 temper.Therefore,dual-RRA temper not only keeps strength equivalent to the RRA temper but also obtains higher EC resistance than T76 temper.展开更多
Exfoliation on as-extruded Mg-1 Li-1 Ca magnesium alloy was investigated after an immersion in 3.5 wt%NaCl aqueous solution for 90, 120 and 150 days through optical microscope, digital camera, scanning electron micros...Exfoliation on as-extruded Mg-1 Li-1 Ca magnesium alloy was investigated after an immersion in 3.5 wt%NaCl aqueous solution for 90, 120 and 150 days through optical microscope, digital camera, scanning electron microscope, electrochemical workstation, scanning Kalvin probe, X-ray diffraction and Fourier transform infrared spectroscope. The results demonstrated that exfoliation corrosion occurred on extruded Mg-1 Li-1 Ca alloy due to elongated microstructure parallel to surface, and delamination of lamellar structure resulted from galvanic effect and wedge effect. Skin layer with fine grains exhibited better corrosion resistance, whereas the interior with coarse grains and the intermetallic compound,Mg2 Ca particles existing in a fibrous structure, dispersed along grain boundaries and extrusion direction in a line. Furthermore, galvanic effect between Mg2 Ca particles and their neighboring a-Mg matrix facilitated dissolution of Mg2 Ca particles and a-Mg matrix; wedge effect was caused by formation of corrosion products. Exfoliation corrosion of extruded Mg-Li-Ca alloys might be a synergic effect of pitting corrosion,filiform corrosion, intergranular corrosion and stress corrosion. Finally, exfoliation corrosion mechanism was proposed.展开更多
Multilayer graphene was prepared by mechanical exfoliation of natural graphite with dioctyl phthalate （DOP） as milling medium without solvent. The obtained mixture could be directly mixed with poly（vinyl chloride）...Multilayer graphene was prepared by mechanical exfoliation of natural graphite with dioctyl phthalate （DOP） as milling medium without solvent. The obtained mixture could be directly mixed with poly（vinyl chloride） （PVC） for melt-forming, with DOP acting as plasticizer and graphene acting as conductive filler for antistatic performance. The composite showed surface resistance of 2.5 ×10 6 Ω/ at 1 wt% carbon additive, significantly lower than approx. 7 wt% of raw graphite required for achieving the same level. This value is low enough for practical antistatic criterion of 3 × 10 8 Ω/ . The effect of filler addition on mechanical performance was minimal, or even beneficial for the milled carbon in contrast to the case of raw graphite.展开更多
Spent cathode carbon(SCC)from aluminum electrolysis is a potential graphite resource.However,full use of the SCC remains a challenge,since it contains many hazardous substances(e.g.,fluoride salts,cyanides),encapsulat...Spent cathode carbon(SCC)from aluminum electrolysis is a potential graphite resource.However,full use of the SCC remains a challenge,since it contains many hazardous substances(e.g.,fluoride salts,cyanides),encapsulated within the thick carbon layers and thus posing serious environmental concerns.This work presents a chemical oxidative exfoliation route to achieve the recycling of SCC and the decontaminated SCC with high-valued graphene oxide(GO)-like carbon structures(SCC-GO)is applied as an excellent adsorbent for organic pollutants.Specifically,after the oxidative exfoliation,the embedded hazardous constituents are fully exposed,facilitating their subsequent removal by aqueous leaching.Moreover,benefiting from the enhanced specific surface areas along with abundant O-containing functional groups,the as-produced SCC-GO,shows an adsorption capacity as high as 347 mg·g^(-1)when considering methylene blue as a pollutant model,which exceeds most of the recently reported carbon-based adsorbents.Our study provides a feasible solution for the efficient recycling of hazardous carbonaceous wastes.展开更多
Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices.Herein,we report a bioinspired nanostructured film with the integration of large ductilit...Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices.Herein,we report a bioinspired nanostructured film with the integration of large ductility and high thermal conductivity based on self-exfoliated pristine graphene and three-dimensional aramid nanofiber network.A self-grinding strategy to directly exfoliate flake graphite into few-layer and few-defect pristine graphene is successfully developed through mutual shear friction between graphite particles,generating largely enhanced yield and productivity in comparison to normal liquid-based exfoliation strategies,such as ultrasonication,high-shear mixing and ball milling.Inspired by nacre,a new bioinspired layered structural design model containing three-dimensional nanofiber network is proposed and implemented with an interconnected aramid nanofiber network and high-loading graphene nanosheets by a developed continuous assembly strategy of sol-gel-film transformation.It is revealed that the bioinspired film not only exhibits nacre-like ductile deformation behavior by releasing the hidden length of curved aramid nanofibers,but also possesses good thermal transport ability by directionally conducting heat along pristine graphene nanosheets.展开更多
The influence of exfoliation corrosion on the tensile properties of a high strength Al-Zn-Mg-Cu alloy was investigated by ambient temperature tensile testing, optical microscopy, transmission electron microscopy （TEM...The influence of exfoliation corrosion on the tensile properties of a high strength Al-Zn-Mg-Cu alloy was investigated by ambient temperature tensile testing, optical microscopy, transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and electron backscatter diffraction （EBSD）. After exfoliation corrosion immersion, blisters and corrosion pits can be seen on the sheet surface, which lead to loss of materials and notches. A number of intergranular cracks are observed to initiate at the bottom of the corrosion-induced notches and propagate rapidly into the bulk materials during tensile. Consequently, exfoliation corrosion results in significant loss of strength and brittle fracture. EBSD results show that the crack propagation path is primarily along the grain boundaries with misorientation of-45°, and coincidence site lattice （CSL） boundaries are slightly more resistant to crack.展开更多
Synthesis of structurally controlled graphene materials is critical for realizing their practical applications.The electrochemical exfoliation of graphite has emerged as a simple method to produce graphene materials.T...Synthesis of structurally controlled graphene materials is critical for realizing their practical applications.The electrochemical exfoliation of graphite has emerged as a simple method to produce graphene materials.This review examines research progress in the last 5 years,from 2015 to 2019.Graphene material synthesis methods generally have a trade‐off between increasing production yield and achieving better material property control.The synthesis conditions for synthesizing pristine graphene,graphene oxide(GO),and graphene composites are significantly different.Thus,in this review,we first discuss synthesis methods for graphene materials with high C/O ratios from four aspects:graphite electrodes,equipment engineering,electrolytes,and additional reduction methods.Next,we survey synthesis methods for GO and examine how the pretreatment of the graphite electrodes,electrolytes,and operation parameters,such as applied voltages,electrolyte temperatures,and mechanical forces,affect the quality of GO.Further,we summarize electrochemical exfoliation methods used to dope graphene materials,introduce covalent functional groups,incorporate various nanoparticles,and assembly of graphene architectures.For all synthesis methods,we compare the properties of resulting graphene materials such as C/O ratios,lateral size,layer numbers,and quality characterized by Raman spectroscopy.Lastly,we propose our perspectives on further research.We hope this review stimulates more studies to realize the on‐demand production of graphene materials with desired properties using electrochemical exfoliation methods.展开更多
The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation fo...The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.展开更多
Graphene nanosheets(GSs) were prepared from graphite oxide by thermal exfoliation method. The effect of thermal exfoliation temperature on the structure and supercapacitive performance of GSs has been investigated. Th...Graphene nanosheets(GSs) were prepared from graphite oxide by thermal exfoliation method. The effect of thermal exfoliation temperature on the structure and supercapacitive performance of GSs has been investigated. The results show that the GSs with pore sizes center around 4.0 nm. With an increase of thermal reduction temperature, the number of stacking layers and the structure disorder degree increase, while the oxygen-containing groups content, BET surface area,and electrical resistivity of GSs decrease. The results indicate that 673 K is the preferable thermal exfoliation temperature to acquire good supercapacitive performance. In this case, the GSs have the best supercapacitive performance(233.1 F g-1) in a 6 mol L-1KOH electrolyte. The prepared GSs at the preferable thermal exfoliation temperature have good rate performance and cycle stability.展开更多
Stanene(Sn)-based materials have been extensively applied in industrial production and daily life,but their potential biomedical application remains largely unexplored,which is due to the absence of the appropriate an...Stanene(Sn)-based materials have been extensively applied in industrial production and daily life,but their potential biomedical application remains largely unexplored,which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials.Herein,we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional(2D)Sn nanosheets(SnNSs).The obtained SnNSs exhibited a typical sheet-like structure with an average size of~100 nm and a thickness of~5.1 nm.After PEGylation,the resulting PEGylated SnNSs(SnNSs@PEG)exhibited good stability,superior biocompatibility,and excellent photothermal performance,which could serve as robust photothermal agents for multi-modal imaging(fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer.Furthermore,we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs,revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal.This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics.This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.展开更多
Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the...Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the electrolyte acid concentration appears to be a critical parameter.However,the effect of the acid concentration,particularly at low concentrations,is still not fully understood.To address this issue,we used a packed bed electrochemical reactor to synthesize seven different electrochemical graphite oxide(EGO)products in 2–16M sulfuric acid.Detailed XRD,XPS,Raman,conductivity and optical microscopy analysis of the products was carried out.We found dilute acid(<10 M)graphite oxides were less crystalline and less oxidized than those produced in stronger acids.The oxygen evolution reaction at the graphite surface appears to affect the structural changes,oxidation mechanism,and electrochemical corrosion of the anode.EGO conductivity is also strongly affected by the electrolyte’s acidity.We show that well oxidized,yet reasonably conductive,single layer graphene oxide can be produced from 7.1M acid.These results broaden our understanding of graphite electrochemistry and will serve to inform future electrochemical graphene synthesis efforts.展开更多
A highly stable and luminescent metal-organic framework(LMOF) with layered structure,namely,C6H4N5OZn(1) has been successfully achieved and fully characterized by single crystal X-ray diffraction,powder X-ray diffract...A highly stable and luminescent metal-organic framework(LMOF) with layered structure,namely,C6H4N5OZn(1) has been successfully achieved and fully characterized by single crystal X-ray diffraction,powder X-ray diffractions,fluorescence titration and thermogravimetry.This blue-light emitting compound 1 exhibit outstanding stability and can detect Fe3+ and Cu2+ in water specifically,presenting potential application in the field of fluorescent probe technology.Fluorescence titration experiments indicate that the detection of Fe3+ ions by 1 is more significant than that of Cu2+ ions in terms of Ksv value.Furthermore,vip-assisted exfoliation of layered MOF 1 is efficiently carried out through ether O—H hydrogen bond or π…π interactions between the layered host structure and intercalated vip molecules(4,4’-oxybisbenzoic acid and triphenylamine).Tyndal scattering was observed in the suspensions of obtained MOF nanosheets.This study shows that the compound 1 with unique metal ion sensing properties can be applied as a probe material in water pollution treatment field,but also opens up the opportunity for synthesizing luminescent MONs through the "bottom-up" vip intercalation methodology.展开更多
To quest for the best combination of mechanical properties and exfoliation corrosion resisting property of Al-Mg-Mn base alloys, and to seek after the effect of Sc and Zr on mechanical and exfoliation corrosion proper...To quest for the best combination of mechanical properties and exfoliation corrosion resisting property of Al-Mg-Mn base alloys, and to seek after the effect of Sc and Zr on mechanical and exfoliation corrosion properties of Al-Mg-Mn alloys, comparative research technique was used, the mechanical properties of Al-Mg-Mn alloys with and without minor Sc and Zr treated by different annealing were measured, the degrees of exfoliation corrosion for these alloys through accelerated exfoliation corrosion test were evaluated, and polarization curves of these alloys were measured, too. The micro-morphologies of corrosion specimens were observed by SEM and the corrosion product was analyzed using EDS. Optical microscope and TEM were used, the relationship between their microstruc-tures and mechanical properties, exfoliation corrosion resisting property was investigated, and the results show that the addition of minor Sc and Zr can enhance the strength greatly and also improve the combination of strength and plasticity. Moreover, the addition of minor Sc, Zr does not cause appreciable decrease of exfoliation corrosion resisting property, the Al-Mg-Mn-Sc-Zr alloy annealed at 350 ℃ for 1 h has excellent combination of mechanical properties and exfoliation corrosion resisting property, the satisfied combination of mechanical properties nad exfoliation corrosion resisting property can be obtained by means of adding minor Sc and Zr, decreasing the content of Mn, and adopting reasonable annealing practice.展开更多
基金supported by Matching Fund from Thammasat University Research Fund,Thammasat University,under Contract No.MF2/2567the ETS scholarship awarded by Sirindhorn International Institute of Technology,Thammasat University。
文摘Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to all reactions,making it essential to understand the electrochemistry of selected TMDs.Tungsten diselenide(WSe_(2))is reactive in gas evolution processes,similar to molybdenum,yet has received limited attention.This work explores how different exfoliation powers affect WSe_(2)structural configurations and their impact on catalytic performance in hydrogen evolution,oxygen evolution,and capacitive behaviour.The study investigates the structural properties of WSe_(2)nanosheets in both liquid(dispersion)and solid(electrode)phases.Low exfoliation power(90.4 W)contributes to well-defined WSe_(2),while higher power(814 W)leads to an increased number of selenium vacancies.These modifications influence key properties such as thickness,band gaps(1.518 to 1.578 eV),exfoliation yield(0.27 to 0.12 mg mL^(-1)),and oxide content(44.3%to 53.9%),resulting in distinct electrochemical behaviours in different electrolytes.WSe_(2)nanosheets exfoliated at higher power exhibit reduced activity in the hydrogen evolution reaction(HER)due to the loss of W–Se bonds and the formation of an amorphous structure,but they show enhanced oxygen evolution reaction(OER)performance,particularly in alkaline media.Additionally,a higher concentration of selenium vacancies improves capacitive performance in acidic conditions due to proton contributions but are less favourable in neutral and basic electrolytes.This study highlights the importance of exfoliation power in tuning the structural properties of WSe_(2)for specific electrochemical applications,advancing the understanding of its synthesis and performance.
基金supported by the Natural Science Foundation of Zhejiang Province,China(LD24B060002)National Key Research and Development Program of China(2021YFB3801102)the Fundamental Research Funds for the Central Universities(226-2024-00060).
文摘The preparation of dispersible MFI-type zeolite nanoparticles with open micropores is challenging.Herein,a rapid and effective ultrasound-assisted liquid-phase exfoliation method along with a freezedrying process for redispersion of calcined silicalite-1(S-1)zeolite nanoparticle aggregates using 3-aminopropanol as an exfoliating agent is demonstrated.The exfoliation of S-1 zeolite nanoparticles is characterized by X-ray diffraction,scanning electron microscopy and DLS particle size analysis.The effects of drying methods of as-synthesized zeolite nanoparticle suspension,zeolite contents in frozen nanoparticle suspension,exfoliating agent concentrations,and zeolite doses in ultrasonic suspension on exfoliation efficiency are systematically investigated.It is found that the S-1 zeolite nanoparticle(~70 nm)achieves a yield up to 95%through a 30 min ultrasonic exfoliation in a 3-aminopropanol solution along with a freeze-drying process.The proposed exfoliation mechanism involves two primary stages:vip molecule insertion followed by water expansion,both substantially enhanced by tip sonication.This work offers a comprehensive understanding of the exfoliation process,provides valuable insights into the dispersion of sintered zeolite nanoparticles.
文摘Background:Enzyme fragility remains a major challenge in research and applications.Free enzymes are highly unstable,inactivated by heat,acid,alkali,or organic solvents,and often lose activity even under optimal storage conditions.Limiting their use in cosmetics.Few commercial products combine acids and enzymes effectively.Objective:To investigate the physicochemical properties,in vitro exfoliation efficacy,and effects on facial skin parameters of a supramolecular acid-enzyme complex(SAE)composed of mandelic acid(MAN),betaine(BET),and composite enzymes(CE;papain and bromelain),thereby establishing a theoretical foundation for cosmetic applications.Methods:The supramolecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy and proton nuclear magnetic resonance(1H NMR)spectroscopy.Dissolution experiments were conducted to compare the solubility of SAE and CE in aqueous solutions.Enzymatic activity assays evaluated the stabilizing effect of supramolecular deep eutectic technology on enzymes.In vitro exfoliation tests assessed acid-enzyme synergy in keratin removal.A 4-week clinical trial evaluated the efficacy of a 2%SAE essence aqueous solution on facial skin parameters.Results:Dissolution experiments confirmed that supramolecular deep eutectic technology significantly improved enzyme solubility.Enzymatic activity tests demonstrated that this technology effectively preserved protease activity,substantially enhancing its practical applicability.Furthermore,in vitro exfoliation efficacy tests revealed that this technology strengthened the synergistic interaction between acids and enzymes and exhibited superior stratum corneum-removing capability of the SAE.In clinical evaluations of efficacy,after 7 days of using the essence containing SAE,the formulation significantly enhanced cheek gloss(+8.08%),while reducing comedones volume(-16.25%).after 28 days,significantly enhanced cheek hydration(+25.0%,SCH),gloss(+15.93%),and smoothness(−7.78%SEsm),while reducing TEWL(−6.86%),sebum(−15.54%),roughness(+16.24%SEr),and pore metrics(volume:−39.98%;count:−30.64%),and decreased comedones(blackheads:−70.33%;Whiteheads:−52.42%;all p<0.05).Conclusion:The supramolecular acid-enzyme complex demonstrates enhanced stability,improved solubility,and superior exfoliation efficacy compared to free enzymes.Clinical results further confirm its multifunctional benefits,including enhancing skin hydration,sebum regulation,barrier repair,pore refinement,and comedolytic effects.This study provides both theoretical and practical foundations for developing stable acid-enzyme combinations in dermatological applications.
基金Projects(62275275,11904239)supported by the National Natural Science Foundation of ChinaProjects(2021JJ40709,2022JJ20080)supported by the Natural Science Foundation of Hunan Province,China。
文摘Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It exhibits negligible interlayer electronic coupling and significant excitonic behavior in the bulk state.Here we substantiate that NbOCl_(2) nanosheets can be exfoliated and effectively size-selected using controlled centrifugation techniques by the liquid phase exfoliation(LPE)method.Spectroscopic measurements displayed that the variations in dispersion were highly dependent on the nanosheet dimensions.The nanosheets seemed to be comparatively defect-free which will be further corroborated by high resolution transmission electron microscopy(HRTEM)and Raman analysis.The size selected nanosheets are unanticipated stable in isopropyl alcohol(IPA),possibly owing to the protective influence of a solvation shell.Additionally,the photothermal conversion response and photothermal stability of nanosized NbOCl_(2) were investigated.Our finding revealed that NbOCl_(2) possesses a robust photothermal agent property,boasting a photothermal conversion efficiency of more than 30%.This underscores its promising potential for various photothermal applications in different fields such as photothermal therapy and thermal energy conversion.
基金financially supported by the Youth talent support program of science and technology association of colleges of Shaanxi Province(Grant No.20190609)the Special scientific research plan of education department of Shaanxi province(Grant No.19JK0190 and 19JK0186)+3 种基金the Natural Science Foundation of Shaanxi Province(Grant No.2019JM508)the Open project of Key laboratory of catalytic foundation and application of Shaanxi province(Grant No.SLGPT2019KF01-23)the Opening Foundation of Shaanxi Key Laboratory of Industrial Automation(No.SLGPT2019KF01-10)the School-level project of Shaanxi University of Technology(Grant No.SLGRC03,SLGRC02)。
文摘With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent properties,such as distinct pleated structures in layers,adjustable direct bandgap,high carrier mobility,moderate on/off ratio,large specific surface area,and various interesting in-layer anisotropies.However,the realization of these excellent properties depends on the preparation of highquality 2 D BP sheets.Electrochemical exfoliation methods are typically performed under mild conditions,thus,these methods are convenient,controllable,and can produce high-quality 2 D BP sheets.This review summarizes research progress in BP sheets preparation through anodic,cathodic,and electrolyte exfoliation in recent years.Different exfoliating methods affect the quality of 2 D BP sheets.Moreover,possible exfoliating mechanisms and the potential applications of different exfoliating methods are summarized and discussed in detail.Lastly,the shortcomings of existing research on electrochemical exfoliation are presented,and suggestions and prospects for future research on the electrochemical exfoliation of 2 D BP are proposed.
基金Project(2012CB619502)supported by the National Basic Research Program of China
文摘The exfoliation corrosion （EFC） behavior of 7050-T6 aluminum alloy treated with various quench transfer time after solution heat treatment was investigated by standard EFC immersion tests, strength loss measurements after EFC tests and electrochemical impedance spectroscope （EIS） technique. The results showed that EFC resistance of the alloy decreased with increasing quench transfer time. Backscattered electron scanning electron microscope （SEM） together with transmission electron microscope （TEM） observations revealed that the coverage ratio and microstructure of precipitates at grain boundary area are the most important factors which influence the EFC susceptibility of the alloy, while precipitate-free zone （PFZ） near grain boundary has no or only a minor effect on it. In addition, galvanostatic measurements of the alloy present a good correlation between EFC resistance and transients in potential. The cumulated number of transients in potential can be used to evaluate EFC resistance of the alloy.
基金Projects (2010CB731701,2012CB619502) supported by the National Basic Research Program of ChinaProject (50721003) supported by the Creative Research Group of National Natural Science Foundation of China
文摘Influence of dual retrogression and re-aging（dual-RRA） temper on microstructure,strength and exfoliation corrosion（EC） behavior of Al-Zn-Mg-Cu alloy was investigated by hardness measurements,tensile properties tests,exfoliation corrosion tests,transmission electron microscopy（TEM） and scanning electron microscopy（SEM） observation combined energy dispersive X-ray detector（EDX） analysis.Dual-RRA temper maintains the matrix precipitates（MPs） similar to RRA temper,meanwhile obtains coarser and sparser grain boundary precipitates（GBPs） as well as higher Cu and lower Zn content compared with T76 temper.Therefore,dual-RRA temper not only keeps strength equivalent to the RRA temper but also obtains higher EC resistance than T76 temper.
基金supported by the National Natural Science Foundation of China (No. 51571134)the SDUST Research Fund (No. 2014TDJH104)
文摘Exfoliation on as-extruded Mg-1 Li-1 Ca magnesium alloy was investigated after an immersion in 3.5 wt%NaCl aqueous solution for 90, 120 and 150 days through optical microscope, digital camera, scanning electron microscope, electrochemical workstation, scanning Kalvin probe, X-ray diffraction and Fourier transform infrared spectroscope. The results demonstrated that exfoliation corrosion occurred on extruded Mg-1 Li-1 Ca alloy due to elongated microstructure parallel to surface, and delamination of lamellar structure resulted from galvanic effect and wedge effect. Skin layer with fine grains exhibited better corrosion resistance, whereas the interior with coarse grains and the intermetallic compound,Mg2 Ca particles existing in a fibrous structure, dispersed along grain boundaries and extrusion direction in a line. Furthermore, galvanic effect between Mg2 Ca particles and their neighboring a-Mg matrix facilitated dissolution of Mg2 Ca particles and a-Mg matrix; wedge effect was caused by formation of corrosion products. Exfoliation corrosion of extruded Mg-Li-Ca alloys might be a synergic effect of pitting corrosion,filiform corrosion, intergranular corrosion and stress corrosion. Finally, exfoliation corrosion mechanism was proposed.
基金financially supported by the National Natural Science Foundation of China (Nos. 51472253 and 51772306)
文摘Multilayer graphene was prepared by mechanical exfoliation of natural graphite with dioctyl phthalate （DOP） as milling medium without solvent. The obtained mixture could be directly mixed with poly（vinyl chloride） （PVC） for melt-forming, with DOP acting as plasticizer and graphene acting as conductive filler for antistatic performance. The composite showed surface resistance of 2.5 ×10 6 Ω/ at 1 wt% carbon additive, significantly lower than approx. 7 wt% of raw graphite required for achieving the same level. This value is low enough for practical antistatic criterion of 3 × 10 8 Ω/ . The effect of filler addition on mechanical performance was minimal, or even beneficial for the milled carbon in contrast to the case of raw graphite.
基金supported by the National Natural Science Foundation of China(22008221)Startup Research Fund of Zhengzhou University(32211716)+3 种基金Key Scientific Research Projects of Colleges and Universities in Henan Province(21A530005)Guangdong Basic and Applied Basic Research Foundation(2021A1515110789)Hunan Provincial Natural Science Foundation of China(2022JJ40431)Zhengzhou Collaborative Innovation Major Project。
文摘Spent cathode carbon(SCC)from aluminum electrolysis is a potential graphite resource.However,full use of the SCC remains a challenge,since it contains many hazardous substances(e.g.,fluoride salts,cyanides),encapsulated within the thick carbon layers and thus posing serious environmental concerns.This work presents a chemical oxidative exfoliation route to achieve the recycling of SCC and the decontaminated SCC with high-valued graphene oxide(GO)-like carbon structures(SCC-GO)is applied as an excellent adsorbent for organic pollutants.Specifically,after the oxidative exfoliation,the embedded hazardous constituents are fully exposed,facilitating their subsequent removal by aqueous leaching.Moreover,benefiting from the enhanced specific surface areas along with abundant O-containing functional groups,the as-produced SCC-GO,shows an adsorption capacity as high as 347 mg·g^(-1)when considering methylene blue as a pollutant model,which exceeds most of the recently reported carbon-based adsorbents.Our study provides a feasible solution for the efficient recycling of hazardous carbonaceous wastes.
基金support from the National Natural Science Foundation of China(51973054)Young Talents Program in Hunan Province(2020RC3024)+2 种基金Natural Science Funds of Hunan Province for Distinguished Young Scholar(2021JJ10018)Science Research Project of Hunan Provincial Education Department(21B0027)High-level Innovative Talent Project in Hunan Province(2018RS3055).
文摘Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices.Herein,we report a bioinspired nanostructured film with the integration of large ductility and high thermal conductivity based on self-exfoliated pristine graphene and three-dimensional aramid nanofiber network.A self-grinding strategy to directly exfoliate flake graphite into few-layer and few-defect pristine graphene is successfully developed through mutual shear friction between graphite particles,generating largely enhanced yield and productivity in comparison to normal liquid-based exfoliation strategies,such as ultrasonication,high-shear mixing and ball milling.Inspired by nacre,a new bioinspired layered structural design model containing three-dimensional nanofiber network is proposed and implemented with an interconnected aramid nanofiber network and high-loading graphene nanosheets by a developed continuous assembly strategy of sol-gel-film transformation.It is revealed that the bioinspired film not only exhibits nacre-like ductile deformation behavior by releasing the hidden length of curved aramid nanofibers,but also possesses good thermal transport ability by directionally conducting heat along pristine graphene nanosheets.
基金Project(2012CB619500) supported by the National Basic Research Program of ChinaProject(201012200238) supported from the Freedom Explore Program of Central South University, China
文摘The influence of exfoliation corrosion on the tensile properties of a high strength Al-Zn-Mg-Cu alloy was investigated by ambient temperature tensile testing, optical microscopy, transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and electron backscatter diffraction （EBSD）. After exfoliation corrosion immersion, blisters and corrosion pits can be seen on the sheet surface, which lead to loss of materials and notches. A number of intergranular cracks are observed to initiate at the bottom of the corrosion-induced notches and propagate rapidly into the bulk materials during tensile. Consequently, exfoliation corrosion results in significant loss of strength and brittle fracture. EBSD results show that the crack propagation path is primarily along the grain boundaries with misorientation of-45°, and coincidence site lattice （CSL） boundaries are slightly more resistant to crack.
基金National Natural Science Foundation of China,Grant/Award Numbers:51678163,91851202Australian Research Council,Grant/Award Number:FT160100107 and DP180102210。
文摘Synthesis of structurally controlled graphene materials is critical for realizing their practical applications.The electrochemical exfoliation of graphite has emerged as a simple method to produce graphene materials.This review examines research progress in the last 5 years,from 2015 to 2019.Graphene material synthesis methods generally have a trade‐off between increasing production yield and achieving better material property control.The synthesis conditions for synthesizing pristine graphene,graphene oxide(GO),and graphene composites are significantly different.Thus,in this review,we first discuss synthesis methods for graphene materials with high C/O ratios from four aspects:graphite electrodes,equipment engineering,electrolytes,and additional reduction methods.Next,we survey synthesis methods for GO and examine how the pretreatment of the graphite electrodes,electrolytes,and operation parameters,such as applied voltages,electrolyte temperatures,and mechanical forces,affect the quality of GO.Further,we summarize electrochemical exfoliation methods used to dope graphene materials,introduce covalent functional groups,incorporate various nanoparticles,and assembly of graphene architectures.For all synthesis methods,we compare the properties of resulting graphene materials such as C/O ratios,lateral size,layer numbers,and quality characterized by Raman spectroscopy.Lastly,we propose our perspectives on further research.We hope this review stimulates more studies to realize the on‐demand production of graphene materials with desired properties using electrochemical exfoliation methods.
基金Jiangsu Province Six Talent Peaks Project(No.2014-XCL-013)Jiangsu Industrial-academicresearch Prospective Joint Project(No.BY2016069-02)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsTop-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B112)。
文摘The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.
基金supported by the National Natural Science Foundation of China (Grant No. 41272051)the Doctor Foundation of Southwest University of Science and Technology (Grant No. 11ZX7135)
文摘Graphene nanosheets(GSs) were prepared from graphite oxide by thermal exfoliation method. The effect of thermal exfoliation temperature on the structure and supercapacitive performance of GSs has been investigated. The results show that the GSs with pore sizes center around 4.0 nm. With an increase of thermal reduction temperature, the number of stacking layers and the structure disorder degree increase, while the oxygen-containing groups content, BET surface area,and electrical resistivity of GSs decrease. The results indicate that 673 K is the preferable thermal exfoliation temperature to acquire good supercapacitive performance. In this case, the GSs have the best supercapacitive performance(233.1 F g-1) in a 6 mol L-1KOH electrolyte. The prepared GSs at the preferable thermal exfoliation temperature have good rate performance and cycle stability.
基金the US METAvivor Early Career Investigator Award(W.T.)and Harvard Medical School/Brigham and Women’s Hospital Department of Anesthesiology-Basic Scientist Grant(W.T.)National Natural Science Foundation of China(Nos.21877049,21807117)+2 种基金Major Program for Tackling Key Problems of Industrial Technology in Guangzhou(201902020013)Dedicated Fund for Promoting High-Quality Marine Economic Development in Guangdong Province(GDOE-2019-A31,2020-035)Dr J.Ouyang was supported by the China Postdoctoral Science Foundation(No.2020M683173).
文摘Stanene(Sn)-based materials have been extensively applied in industrial production and daily life,but their potential biomedical application remains largely unexplored,which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials.Herein,we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional(2D)Sn nanosheets(SnNSs).The obtained SnNSs exhibited a typical sheet-like structure with an average size of~100 nm and a thickness of~5.1 nm.After PEGylation,the resulting PEGylated SnNSs(SnNSs@PEG)exhibited good stability,superior biocompatibility,and excellent photothermal performance,which could serve as robust photothermal agents for multi-modal imaging(fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer.Furthermore,we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs,revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal.This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics.This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.
基金support from the Australian Research Council (LP160101521 and DP190100120)
文摘Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the electrolyte acid concentration appears to be a critical parameter.However,the effect of the acid concentration,particularly at low concentrations,is still not fully understood.To address this issue,we used a packed bed electrochemical reactor to synthesize seven different electrochemical graphite oxide(EGO)products in 2–16M sulfuric acid.Detailed XRD,XPS,Raman,conductivity and optical microscopy analysis of the products was carried out.We found dilute acid(<10 M)graphite oxides were less crystalline and less oxidized than those produced in stronger acids.The oxygen evolution reaction at the graphite surface appears to affect the structural changes,oxidation mechanism,and electrochemical corrosion of the anode.EGO conductivity is also strongly affected by the electrolyte’s acidity.We show that well oxidized,yet reasonably conductive,single layer graphene oxide can be produced from 7.1M acid.These results broaden our understanding of graphite electrochemistry and will serve to inform future electrochemical graphene synthesis efforts.
基金financially supported by the National Natural Science Foundation of China(No.21671084)NSF of Jiangsu Province(No.BK20131244)+5 种基金Six talent peaks project in Jiangsu Province(No.2014-XCL-008)the Qing Lan Project of Jiangsu Provincethe Innovation Program of Graduate Students in JiangsuProvince(No.KYLX16-0508)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionInnovation Program for Graduate Student from Jiangsu University of Science and Technology(No.YCX15S-19)the Foundation of Jiangsu Educational Committee(No.16KJB430011)。
文摘A highly stable and luminescent metal-organic framework(LMOF) with layered structure,namely,C6H4N5OZn(1) has been successfully achieved and fully characterized by single crystal X-ray diffraction,powder X-ray diffractions,fluorescence titration and thermogravimetry.This blue-light emitting compound 1 exhibit outstanding stability and can detect Fe3+ and Cu2+ in water specifically,presenting potential application in the field of fluorescent probe technology.Fluorescence titration experiments indicate that the detection of Fe3+ ions by 1 is more significant than that of Cu2+ ions in terms of Ksv value.Furthermore,vip-assisted exfoliation of layered MOF 1 is efficiently carried out through ether O—H hydrogen bond or π…π interactions between the layered host structure and intercalated vip molecules(4,4’-oxybisbenzoic acid and triphenylamine).Tyndal scattering was observed in the suspensions of obtained MOF nanosheets.This study shows that the compound 1 with unique metal ion sensing properties can be applied as a probe material in water pollution treatment field,but also opens up the opportunity for synthesizing luminescent MONs through the "bottom-up" vip intercalation methodology.
文摘To quest for the best combination of mechanical properties and exfoliation corrosion resisting property of Al-Mg-Mn base alloys, and to seek after the effect of Sc and Zr on mechanical and exfoliation corrosion properties of Al-Mg-Mn alloys, comparative research technique was used, the mechanical properties of Al-Mg-Mn alloys with and without minor Sc and Zr treated by different annealing were measured, the degrees of exfoliation corrosion for these alloys through accelerated exfoliation corrosion test were evaluated, and polarization curves of these alloys were measured, too. The micro-morphologies of corrosion specimens were observed by SEM and the corrosion product was analyzed using EDS. Optical microscope and TEM were used, the relationship between their microstruc-tures and mechanical properties, exfoliation corrosion resisting property was investigated, and the results show that the addition of minor Sc and Zr can enhance the strength greatly and also improve the combination of strength and plasticity. Moreover, the addition of minor Sc, Zr does not cause appreciable decrease of exfoliation corrosion resisting property, the Al-Mg-Mn-Sc-Zr alloy annealed at 350 ℃ for 1 h has excellent combination of mechanical properties and exfoliation corrosion resisting property, the satisfied combination of mechanical properties nad exfoliation corrosion resisting property can be obtained by means of adding minor Sc and Zr, decreasing the content of Mn, and adopting reasonable annealing practice.
