Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates sign...Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates significantly at elevated temperatures exceeding 600℃,primarily due to the collapse of pore structure.Meanwhile,the shielding capacity of SiO_(2) aerogel to the infrared radiation at high temperature is rather low due to the intrinsic properties of SiO_(2).Herein,a strategy for improving the high-temperature stability and infrared shielding properties of SiO_(2) aerogel via Ca doping was explored.Calcium-doped silica aerogel(CSA)powders were prepared by Sol-Gel,hydrothermal,and ambient pressure drying(APD)techniques using water glass and anhydrous calcium chloride as precursors and trimethylchlorosilane as a hydrophobic modifier.The effects of Ca/Si molar ratio in the precursor and hydrothermal conditions(temperature and pH)on the crystalline properties,microscopic morphology and pore structure of CSAs were investigated.The results show that the Ca/Si molar ratio and hydrothermal treatment have significant effects on the microstructure and heat resistance of CSAs in the temperature range of 400-1000℃.The samples sintered at 1000℃have a high specific surface area of 100.1 m^(2)/g and a pore volume of 0.8705 cm^(3)/g,indicating that the CSA has good heat resistance.One-side insulation tests at temperatures up to 600℃show that the sample with a Ca/Si molar ratio of 1.0 has the best insulation performance,with a cold surface temperature of 450℃,which is 27℃lower than that of the pure silica aerogel.展开更多
Aerogels,renowned as ultra-lightweight solids with exceptional porosity and specific surface area,have emerged as pivotal materials for thermal insulation,catalysis,energy storage,and biomedicine.This review comprehen...Aerogels,renowned as ultra-lightweight solids with exceptional porosity and specific surface area,have emerged as pivotal materials for thermal insulation,catalysis,energy storage,and biomedicine.This review comprehensively evaluates the recent strides in sustainable,high-performance cellulose-based aerogels,emphasizing their fabrication,functionalization,and application prospects.It details the extraction of cellulose fromdiverse sources and its subsequent processing into nanocellulose(e.g.,cellulose nanofibrils and nanocrystals),which serves as the fundamental building block for aerogel synthesis.The critical sol-gel transition,solvent selection,and the pivotal role of drying techniques—freeze-drying,supercritical drying,and ambient pressure drying—in determining final aerogel architecture and properties are systematically analyzed.Special emphasis is placed on the advanced chemical modification of nanocellulose,including esterification,click chemistry,etherification,silanization,and amidation,which tailors surface chemistry to impart hydrophobicity,reactivity,or specific binding sites.The profound influence of cellulose source characteristics(aspect ratio,crystallinity,surface charge)on the pore-forming mechanism and aerogel performance is thoroughly discussed,bridging raw material selection with microstructure design.The review further elucidates the engineering of hybrid and composite aerogels by integrating silica,graphene,polymers,semiconductors,and metal-organic frameworks(MOFs),which synergistically enhance functionalities for targeted applications such as adsorption,photocatalysis,energy storage,sensing,and biomedical engineering.Despite significant progress,challenges remain in scalable green fabrication,balancing ultra-high porosity with mechanical robustness,and deepening the mechanistic understanding in complex applications.This work consolidates the current state-of-the-art,identifies key knowledge gaps,and provides a forward-looking perspective on the development of cellulose aerogels as versatile platforms for next-generation sustainable technologies.展开更多
Aerogels are ultra-lightweight,porous materials defined by a complex network of interconnected pores and nanostructures,which effectively suppress heat transfer,making them exceptional for thermal insulation.Furthermo...Aerogels are ultra-lightweight,porous materials defined by a complex network of interconnected pores and nanostructures,which effectively suppress heat transfer,making them exceptional for thermal insulation.Furthermore,their porous architecture can trap and scatter light via multiple internal reflections,extending the optical path within the material.When combined with suitable light-absorbing materials,this feature significantly enhances light absorption(darkness).To validate this concept,mesoporous silica aerogel particles were incorporated into a resorcinol-formaldehyde(RF)sol,and the silica-to-RF ratio was optimized to achieve uniform carbon compound coatings on the silica pore walls.Notably,increasing silica loading raised the sol viscosity,enabling formulations ideal for direct ink writing processes with excellent shape fidelity for super-black topographical designs.The printed silica-RF green bodies exhibited remarkable mechanical strength and ultra-low thermal conductivity(15.8 m W m^(-1) K^(-1))prior to pyrolysis.Following pyrolysis,the composites maintained structural integrity and printed microcellular geometries while achieving super-black coloration(abs.99.56%in the 280-2500 nm range)and high photothermal conversion efficiency(94.2%).Additionally,these silica-carbon aerogel microcellulars demonstrated stable electrical conductivity and low electrochemical impedance.The synergistic combination of 3D printability and super-black photothermal features makes these composites highly versatile for multifunctional applications,including on-demand thermal management,and efficient solar-driven water production.展开更多
The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precis...The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precisely regulate the growth and stacking of COF grains through a moderate reversed Schiff base reaction,realizing the direct synthesis of COF nanofibers(CNFs)with high aspect ratio(L/D=103.05)and long length(>20μm).An individual CNF exhibits a biomimetic scale-like architecture,achieving superior flexibility and fatigue resistance under dynamic bending via a multiscale stress dissipation mechanism.Taking advantages of these structural features,we engineer CNF aerogels(CNF-As)with programmable porous structures(e.g.,honeycomb,lamellar,isotropic)via directional ice-template methodology.CNF-As demonstrate 100%COF content,high specific surface area(396.15 m^(2)g^(-1))and superelasticity(~0%elastic deformation after 500 compression cycles at 50%strain),outperforming most COF-based counterparts.Compared with the conventional COF aerogels,the unique structural features of CNF-A enable it to perform outstandingly in uranium extraction,with an 11.72-fold increment in adsorption capacity(920.12 mg g^(-1))and adsorption rate(89.9%),and a 2.48-fold improvement in selectivity(U/V=2.31).This study provides a direct strategy for the development of next-generation COF materials with outstanding functionality and structural robustness.展开更多
Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous arch...Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous architecture of such gels often promote intense molecular motion and facilitate oxygen diffusion,which can severely quench phosphorescence under ambient conditions.In this work,we report a versatile strategy for constructing high-performance organic RTP materials by leveraging organic aerogels,which exhibit superior luminescent,mechanical,and thermal properties.Owing to their structural advantages,these organic aerogels possess a three-dimensional rigid framework that enhances intersystem crossing(ISC)efficiency and promotes multiple intermolecular interactions,thereby enabling efficient RTP with an ultralong phosphorescent lifetime of up to 1007 ms.Notably,the resulting RTP aerogels demonstrate exceptional structural robustness(compression modulus of 1 MPa),excellent thermal insulation(peak heat release rate reduced to 31.1 kW/m^(2)),and outstanding flame retardancy(limiting oxygen index exceeding 90%),positioning them among the most multifunctional organic aerogels reported to date.Given their balanced combination of RTP performance,mechanical resilience,and thermal stability,these phosphorescent aerogels represent a highly promising platform for the development of advanced,multifunctional organic RTP materials.展开更多
Outlast Technologies GmbH has been awarded the WTiN Innovate Textile Award in the category Material Innovation for Aersulate®,its aerogel-infused insulation technology.The award honors outstanding achievements in...Outlast Technologies GmbH has been awarded the WTiN Innovate Textile Award in the category Material Innovation for Aersulate®,its aerogel-infused insulation technology.The award honors outstanding achievements in advanced material development and textile innovation.Aersulate® marks a significant advancement in thermal insulation.The technology integrates aerogel,whose highly porous structure efficiently traps air,delivering exceptional thermal performance at extremely low weight and minimal thickness.In AersulateR wadding,aerogel accounts for approximately 50%of the material volume,enabling superior insulation without bulk.展开更多
The effective and environmentally friendly management of oily wastewater,alongside the beneficial conversion of waste biomass,holds paramount importance for environmental conservation,public health,and sustainable soc...The effective and environmentally friendly management of oily wastewater,alongside the beneficial conversion of waste biomass,holds paramount importance for environmental conservation,public health,and sustainable societal progress.In this research,an innovative biomass core-shell bioreactor(CGC@SiO_(2) aerogel) with selective adsorption and degradation properties was developed.The reactor's core is composed of coffee cellulose aerogel,offering a porous framework conducive to microbial colonization while safeguarding microorganisms from adverse external factors.The shell integrates hydrophobic silica enriched with polydimethylsiloxane,which alters the material's hydrophilic properties,enabling it to remain afloat on water for up to 100 days.This superhydrophobic layer maintained a contact angle of 150° even after ten consecutive rubbings.Experimental results indicate that the material performs exceptionally well in oil-water separation,as demonstrated by its success in 9 consecutive oil-water separations.It achieved 99 % selective adsorption,91 % removal,and 46.2 % degradation of a 3 wt.% diesel solution under conditions of 37℃,120 r/min,and pH=7.Additionally,tests assessing environmental tolerance revealed the material's robust adaptability and stability across varying pH levels and temperatures.Compared to traditional hydrophobic and lipophilic materials or free-floating microorganisms,CGC@SiO2 aerogel not only efficiently captures oil pollutants but also degrades them into non-hazardous substances.Combining biodegradation with selective adsorption has shown to be an effective approach for treating oily wastewater,offering significant practical application potential.The low-carbon production of CGC@SiO2aerogel aligns with circular economy principles,underscoring its role in sustainable development.展开更多
Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedst...Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedstocks,which undoubtedly increases carbon emissions from production in the nuclear industry.Here,a biomass aerogel(CS-BT)is prepared by the facile cross-linking of chitosan and bayberry tannins with glutaraldehyde.U(Ⅵ)can be adsorbed by hydroxyl groups on CS-BT aerogel via chelation,and the maximum adsorption capacity of the obtained aerogel to U(Ⅵ)is 140 mg·g^(-1)and the removal rate reaches up to 99%(at 298.15 K,pH=5.0).The pseudo-second-order kinetics model and Freundlich model can better match the adsorption process of CS-BT aerogel,implying that its adsorption is a chemical adsorption process dominated by multilayer adsorption.The thermodynamic results show that the adsorption process of U(Ⅵ)by CS-BT aerogel is spontaneous and exothermic.Hence,our biomass aerogel can effectively extract uranium from water,contributing to the sustainable development of the nuclear industry.展开更多
With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the...With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.展开更多
Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and...Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.展开更多
As a core technology in flexible electronics systems,piezoresistive sensors exhibit significant application value in frontier fields such as medical health monitoring,intelligent human-machine collaboration,and bionic...As a core technology in flexible electronics systems,piezoresistive sensors exhibit significant application value in frontier fields such as medical health monitoring,intelligent human-machine collaboration,and bionic robot perception.A novel flexible piezoresistive sensing material was developed by combining biomass-derived carbon aerogel(CC)with polydimethylsiloxane(PDMS).The composites had excellent fatigue resistance,maintaining more than 90%shape recovery and less than 3.8%residual deformation after 100000 cycles at 30%strain.Furthermore,combining biomass-derived carbon aerogel with polydimethylsiloxane composites exhibited excellent piezoresistive response characteristics at different temperatures.In the temperature range from-30℃to 100℃,its resistance decreased with increasing temperature,while showing a shortened response time.The composite achieved a stable resistance response through the reversible contact of the conductive network under the action of external forces and had a wide linear detection range,high sensitivity,and effective differentiation between static pressure and dynamic deformation signals.This work established the correlation between the microscopic deformation of the carbon skeleton and the macroscopic electrical behavior,and verified the stability and durability of combining biomass-derived carbon aerogel with polydimethylsiloxane composites under complex stress conditions.The collaborative design strategy provides an innovative platform for the development of sustainable,high-performance flexible sensors with important potential applications in health monitoring and intelligent human-machine interfaces.展开更多
Ceramic aerogels(CAs)have emerged as a significant research frontier across various applications due to their lightweight,high porosity,and easily tunable structural characteristics.However,the intrinsic weak interact...Ceramic aerogels(CAs)have emerged as a significant research frontier across various applications due to their lightweight,high porosity,and easily tunable structural characteristics.However,the intrinsic weak interactions among the constituent nanoparticles,coupled with the limited toughness of traditional CAs,make them susceptible to structural collapse or even catastrophic failure when exposed to complex mechanical external forces.Unlike 0D building units,1D ceramic nanofibers(CNFs)possess a high aspect ratio and exceptional flexibility simultaneously,which are desirable building blocks for elastic CAs.This review presents the recent progress in electrospun ceramic nanofibrous aerogels(ECNFAs)that are constructed using ECNFs as building blocks,focusing on the various preparation methods and corresponding structural characteristics,strategies for optimizing mechanical performance,and a wide range of applications.The methods for preparing ECNFs and ECNFAs with diverse structures were initially explored,followed by the implementation of optimization strategies for enhancing ECNFAs,emphasizing the improvement of reinforcing the ECNFs,establishing the bonding effects between ECNFs,and designing the aggregate structures of the aerogels.Moreover,the applications of ECNFAs across various fields are also discussed.Finally,it highlights the existing challenges and potential opportunities for ECNFAs to achieve superior properties and realize promising prospects.展开更多
Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of ma...Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.展开更多
To address the poor mechanical properties of polydimethylsiloxane(PDMS)and enhance the understanding of the reinforcement mechanisms of aerogel network structures in rubber matrices,this study reinforced PDMS using an...To address the poor mechanical properties of polydimethylsiloxane(PDMS)and enhance the understanding of the reinforcement mechanisms of aerogel network structures in rubber matrices,this study reinforced PDMS using an ordered interconnected three-dimensional montmorillonite(MMT)aerogel network.The average pore diameter of the aerogels was successfully reduced from 11.53μm to 2.51μm by adjusting the ratio of poly(vinyl alcohol)(PVA)to MMT via directional freezing.Changes in the aerogel network were observed in field emission scanning electron microscope(FESEM)images.After vacuum impregnation,the aerogel network structure of the composites was observed using FESEM.Tensile tests indicated that as the pore diameter decreased,the elongation at break of the composites first increased to a peak of329.61%before decreasing,while the tensile strength and Young's modulus continuously increased to their maximum values of 6.29 MPa and24.67 MPa,respectively.Meanwhile,FESEM images of the tensile cracks and fracture surfaces showed that with a reduction in aerogel pore diameter,the degrees of crack deflection and interfacial debonding increased,presenting a rougher fracture surface.These phenomena enable the composites to dissipate substantial energy during tension,thus effectively improving the mechanical strength of the composites.The present work elucidates the bearing of ordered three-dimensional aerogel network structures on the performance of rubber matrices and provides crucial theoretical insights and technical guidance for the creation and optimization of high-performance PDMS-based composites.展开更多
With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite h...With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.展开更多
Due to excellent thermal insulation performance at room temperature and ultralow density,silica aero-gels are candidates for thermal insulation.However,at high temperatures,the thermal insulation prop-erty of silica a...Due to excellent thermal insulation performance at room temperature and ultralow density,silica aero-gels are candidates for thermal insulation.However,at high temperatures,the thermal insulation prop-erty of silica aerogels decreased greatly caused by transparency to heat radiation.Opacifiers introduced into silica sol can block heat radiation yet destroy the uniformity of aerogels.Herein,we designed and prepared a silica aerogel composite with oriented and layered silica fibers(SFs),SiC nanowires(SiC_(NWs)),and silica aerogels,which were prepared by papermaking,chemical vapor infiltration(CVI),and sol-gel respectively.Firstly,oriented and layered SFs made still air a wall to block heat transfer by the solid phase.Secondly,SiC_(NWs) were grown in situ on the surface of SFs evenly to weave into the network,and the network reduced the gaseous thermal conductivity by dividing cracks in SFs/SiC_(NWs)/SA.Thirdly,SiC_(NWs) weakened the heat transfer by radiation at high temperatures.Therefore,SFs/SiC_(NWs)/SA presented remarkable thermal insulation(0.017 W(m K)^(-1) at 25℃,0.0287 W(m K)^(-1) at 500℃,and 0.094 W(m K)^(-1) at 1000℃).Besides,SFs/SiC_(NWs)/SA exhibited remarkable thermal stability(no size transform after being heat treated at 1000℃ for 1800 s)and tensile strength(0.75 MPa).These integrated properties made SFs/SiC_(NWs)/SA a promising candidate for highly efficient thermal insulators.展开更多
Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abund...Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abundant surface defects are considered to be excellent substrate materials for reducing Pt agglomeration and enhancing catalytic activity.Herein,Pt-based GA composites(Pt-GA-x)featuring homogeneous particle dispersion and high activity were successfully synthesized through a one-step reduction method.Fourier transform infrared(FTIR),Raman,and X-ray photoelectron spectroscopy(XPS)test results indicate that the presence of a large number of oxygen-containing functionalities in GA for anchoring Pt NPs,and the interaction with GA produces electronically structured Pt and defect-rich GA substrates.The obtained electrocatalyst Pt-GA-2 possesses a large specific surface area(443.46 m^(2)·g^(−1)),low Pt loading(3.08 wt%),and uniformly dispersed Pt NPs(average 42 nm).As an advanced hydrogen evolution reaction(HER)electrocatalyst,an overpotential of 34 mV is achieved at a current density of 10 mA·cm^(−2)in 0.5 M H_(2)SO_(4)electrolyte,together with a low Tafel slope of 33.2 mV·dec^(−1).Hence,high mass activity(5623 mA·mgPt^(−1))and turnover frequency(TOF=2.57 s^(−1)at η=100 mV)can be obtained,which are 6.81 and 6.76 times higher than those of commercial Pt/C catalysts.All these are attributed to enormous surface defects over GA and electron enrichment on Pt NPs.The present study highlights the unique advantages of GA in electrochemical energy conversion and provides new avenues to fabricate advanced HER electrocatalysts.展开更多
As the application scenarios of aerogels expand,higher requirements are put forward for the materials used to prepare aerogels.Due to the unique chemical structure,polytetrafluoroethylene(PTFE)has excellent properties...As the application scenarios of aerogels expand,higher requirements are put forward for the materials used to prepare aerogels.Due to the unique chemical structure,polytetrafluoroethylene(PTFE)has excellent properties such as high-temperature resistance,hydrophobicity,and chemical stability.However,the PTFE aerogels are difficult to be molded due to the weak interaction between resin particles.In this work,poly(ethylene oxide)(PEO)was selected as the carrier to assist the PTFE aerogels molding.The pure PTFE aerogels were prepared by homogeneously mixing PTFE aqueous dispersion and PEO,freeze-drying,and high-temperature sintering.When the mass fraction of PTFE and PEO were appropriate,the porosity of PTFE aerogels exceeded 90%and had a hierarchical honeycomb structure.Results showed that the PTFE aerogels not only had excellent hydrophobicity but also possessed superior acoustic insulation,mechanical strength,thermal insulation,and heat resistance properties.Specifically,the water contact angle is about 140°.The noise reduction coefficient is 0.34 and the average sound absorption coefficient is greater than 88%in the frequency range of 2000-6400 Hz.Meanwhile,the thermal conductivity in the air is about 0.045 W/(m·K),and the initial thermal decomposition temperature is 450℃.More importantly,the PTFE aerogels had excellent temperature and corrosion resistance.Even after extremely thermal and chemical treatment,they remained unchanged porous structure as well as acoustic and thermal insulation properties,which exhibits great potential for application in many harsh environments.展开更多
Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreo...Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreover,due to the accumulation of COFs nanoparticles,it is not conducive to the full utilization of their surface functional groups.Currently,the strategy of COFs assembling into aerogel can be a good solution to this problem.Herein,we successfully synthesize composite aerogels(CSR)by in-situ self-assembly of two-dimensional COFs and graphene based on crosslinking of sodium alginate.Sodium alginate in the composite improves the mechanical properties of the aerogel,and graphene provides a template for the in-situ growth of COFs.Impressively,CSR aerogels with different COFs and sizes can be prepared by changing the moiety of the ligand and modulating the addition amount of COFs.The prepared CSR aerogels exhibit porous,low density,good processability and good mechanical properties.Among them,the density of CSR-N-1.6 is only 5 mg/cm3,which is the lowest density among the reported COF aerogels so far.Due to these remarkable properties,CSR aerogels perform excellent adsorption and recycling properties for the efficient and rapid removal of organic pollutants(organic dyes and antibiotics)from polluted water.In addition,it is also possible to visually recognize the presence of antibiotics by fluorescence detection.This work not only provides a new strategy for synthesizing COF aerogels,but also accelerates the practical application of COF aerogels and contributes to environmental remediation.展开更多
Multifunctional compatible stealth materials have emerged as the focal point of contemporary protection technology research and vanadium-based nanomaterials play a pivotal role in the development of advanced stealth m...Multifunctional compatible stealth materials have emerged as the focal point of contemporary protection technology research and vanadium-based nanomaterials play a pivotal role in the development of advanced stealth materials.Here,a compatible stealth aerogel is successfully synthesized by employing mixed-valence decavanadate as the vanadium oxide(VO_(x))molecular model.Ultralight{V^(Ⅳ)VV_(9)}/MXene aerogel(0.0429 g cm^(-3))exhibits exceptional radar stealth performance with a minimal reflection loss(RL_(min))of−57.74 dB(99.9998%EMW absorption)and a significantly superior radar cross section reduction value of 26.77 dB m2.The aerogel’s exceptional properties,including a low infrared(IR)emissivity(0.479)and a low thermal conductivity of(32.30 mW m^(-1)K^(-1)),are crucial for enabling compatibility with IR and thermal stealth technologies.The presence of a mixed-valence polyoxovanadate cluster leads to an increase in the Schottky barrier and enhances magnetic properties,consequently boosting interfacial polarization and contributing to magnetic losses during electromagnetic wave(EMW)absorption.Consequently,altering the number of valence electrons significantly enhances the compatible stealth capabilities.These findings contribute significantly to our comprehension of how microstructure impacts EMW absorption processes and provide a basis for further research into the development of VO_(x)-based compatible stealth materials.展开更多
文摘Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates significantly at elevated temperatures exceeding 600℃,primarily due to the collapse of pore structure.Meanwhile,the shielding capacity of SiO_(2) aerogel to the infrared radiation at high temperature is rather low due to the intrinsic properties of SiO_(2).Herein,a strategy for improving the high-temperature stability and infrared shielding properties of SiO_(2) aerogel via Ca doping was explored.Calcium-doped silica aerogel(CSA)powders were prepared by Sol-Gel,hydrothermal,and ambient pressure drying(APD)techniques using water glass and anhydrous calcium chloride as precursors and trimethylchlorosilane as a hydrophobic modifier.The effects of Ca/Si molar ratio in the precursor and hydrothermal conditions(temperature and pH)on the crystalline properties,microscopic morphology and pore structure of CSAs were investigated.The results show that the Ca/Si molar ratio and hydrothermal treatment have significant effects on the microstructure and heat resistance of CSAs in the temperature range of 400-1000℃.The samples sintered at 1000℃have a high specific surface area of 100.1 m^(2)/g and a pore volume of 0.8705 cm^(3)/g,indicating that the CSA has good heat resistance.One-side insulation tests at temperatures up to 600℃show that the sample with a Ca/Si molar ratio of 1.0 has the best insulation performance,with a cold surface temperature of 450℃,which is 27℃lower than that of the pure silica aerogel.
基金funded by Basic Scientific Research Funds Project of Heilongjiang Universities of Department of Education,Heilongjiang Province,China,grant number 2025-KYYWF-ZR0763.
文摘Aerogels,renowned as ultra-lightweight solids with exceptional porosity and specific surface area,have emerged as pivotal materials for thermal insulation,catalysis,energy storage,and biomedicine.This review comprehensively evaluates the recent strides in sustainable,high-performance cellulose-based aerogels,emphasizing their fabrication,functionalization,and application prospects.It details the extraction of cellulose fromdiverse sources and its subsequent processing into nanocellulose(e.g.,cellulose nanofibrils and nanocrystals),which serves as the fundamental building block for aerogel synthesis.The critical sol-gel transition,solvent selection,and the pivotal role of drying techniques—freeze-drying,supercritical drying,and ambient pressure drying—in determining final aerogel architecture and properties are systematically analyzed.Special emphasis is placed on the advanced chemical modification of nanocellulose,including esterification,click chemistry,etherification,silanization,and amidation,which tailors surface chemistry to impart hydrophobicity,reactivity,or specific binding sites.The profound influence of cellulose source characteristics(aspect ratio,crystallinity,surface charge)on the pore-forming mechanism and aerogel performance is thoroughly discussed,bridging raw material selection with microstructure design.The review further elucidates the engineering of hybrid and composite aerogels by integrating silica,graphene,polymers,semiconductors,and metal-organic frameworks(MOFs),which synergistically enhance functionalities for targeted applications such as adsorption,photocatalysis,energy storage,sensing,and biomedical engineering.Despite significant progress,challenges remain in scalable green fabrication,balancing ultra-high porosity with mechanical robustness,and deepening the mechanistic understanding in complex applications.This work consolidates the current state-of-the-art,identifies key knowledge gaps,and provides a forward-looking perspective on the development of cellulose aerogels as versatile platforms for next-generation sustainable technologies.
基金financially supported by the Swiss National Science Foundation(grant number IZLRZ2_164058)the China Scholarship Council Ph.D.student exchange programthe Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD)。
文摘Aerogels are ultra-lightweight,porous materials defined by a complex network of interconnected pores and nanostructures,which effectively suppress heat transfer,making them exceptional for thermal insulation.Furthermore,their porous architecture can trap and scatter light via multiple internal reflections,extending the optical path within the material.When combined with suitable light-absorbing materials,this feature significantly enhances light absorption(darkness).To validate this concept,mesoporous silica aerogel particles were incorporated into a resorcinol-formaldehyde(RF)sol,and the silica-to-RF ratio was optimized to achieve uniform carbon compound coatings on the silica pore walls.Notably,increasing silica loading raised the sol viscosity,enabling formulations ideal for direct ink writing processes with excellent shape fidelity for super-black topographical designs.The printed silica-RF green bodies exhibited remarkable mechanical strength and ultra-low thermal conductivity(15.8 m W m^(-1) K^(-1))prior to pyrolysis.Following pyrolysis,the composites maintained structural integrity and printed microcellular geometries while achieving super-black coloration(abs.99.56%in the 280-2500 nm range)and high photothermal conversion efficiency(94.2%).Additionally,these silica-carbon aerogel microcellulars demonstrated stable electrical conductivity and low electrochemical impedance.The synergistic combination of 3D printability and super-black photothermal features makes these composites highly versatile for multifunctional applications,including on-demand thermal management,and efficient solar-driven water production.
基金supported by the National Natural Science Foundation of China(No.52403035)the Shanghai Sailing Program(23YF1400300)+1 种基金the Fundamental Research Funds for the Central Universities(2232023D-05)the Weiqiao Teaching and Research Innovation Program.
文摘The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precisely regulate the growth and stacking of COF grains through a moderate reversed Schiff base reaction,realizing the direct synthesis of COF nanofibers(CNFs)with high aspect ratio(L/D=103.05)and long length(>20μm).An individual CNF exhibits a biomimetic scale-like architecture,achieving superior flexibility and fatigue resistance under dynamic bending via a multiscale stress dissipation mechanism.Taking advantages of these structural features,we engineer CNF aerogels(CNF-As)with programmable porous structures(e.g.,honeycomb,lamellar,isotropic)via directional ice-template methodology.CNF-As demonstrate 100%COF content,high specific surface area(396.15 m^(2)g^(-1))and superelasticity(~0%elastic deformation after 500 compression cycles at 50%strain),outperforming most COF-based counterparts.Compared with the conventional COF aerogels,the unique structural features of CNF-A enable it to perform outstandingly in uranium extraction,with an 11.72-fold increment in adsorption capacity(920.12 mg g^(-1))and adsorption rate(89.9%),and a 2.48-fold improvement in selectivity(U/V=2.31).This study provides a direct strategy for the development of next-generation COF materials with outstanding functionality and structural robustness.
基金supported by the National Natural Science Foundation of China(22475172 and 52203242)the Zhejiang Provincial Natural Science Foundation of China(LQ23B020004)the Fundamental Research Funds for the Central Universities.
文摘Gel-based room-temperature phosphorescence(RTP)materials have garnered significant attention due to their promising applications in flexible electronics and photonics.However,the inherent swollen state and porous architecture of such gels often promote intense molecular motion and facilitate oxygen diffusion,which can severely quench phosphorescence under ambient conditions.In this work,we report a versatile strategy for constructing high-performance organic RTP materials by leveraging organic aerogels,which exhibit superior luminescent,mechanical,and thermal properties.Owing to their structural advantages,these organic aerogels possess a three-dimensional rigid framework that enhances intersystem crossing(ISC)efficiency and promotes multiple intermolecular interactions,thereby enabling efficient RTP with an ultralong phosphorescent lifetime of up to 1007 ms.Notably,the resulting RTP aerogels demonstrate exceptional structural robustness(compression modulus of 1 MPa),excellent thermal insulation(peak heat release rate reduced to 31.1 kW/m^(2)),and outstanding flame retardancy(limiting oxygen index exceeding 90%),positioning them among the most multifunctional organic aerogels reported to date.Given their balanced combination of RTP performance,mechanical resilience,and thermal stability,these phosphorescent aerogels represent a highly promising platform for the development of advanced,multifunctional organic RTP materials.
文摘Outlast Technologies GmbH has been awarded the WTiN Innovate Textile Award in the category Material Innovation for Aersulate®,its aerogel-infused insulation technology.The award honors outstanding achievements in advanced material development and textile innovation.Aersulate® marks a significant advancement in thermal insulation.The technology integrates aerogel,whose highly porous structure efficiently traps air,delivering exceptional thermal performance at extremely low weight and minimal thickness.In AersulateR wadding,aerogel accounts for approximately 50%of the material volume,enabling superior insulation without bulk.
基金supported by the National Natural Science Foundation of China(Nos.22365026 and 21966028)the Science and Technology Project of Gansu(No.21YF5GA062)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.31920220043,31920240094,and 31920230142)the Education Department of Gansu Province:Excellent Graduate student“Innovation Star”project(No.2023CXZX-202)Gansu Province Science Foundation for Youths(No.24JRRA160)the Funds for Special Projects of the Central Government in Guidance of Local Science and Technology Development(No.24ZY1QA026).
文摘The effective and environmentally friendly management of oily wastewater,alongside the beneficial conversion of waste biomass,holds paramount importance for environmental conservation,public health,and sustainable societal progress.In this research,an innovative biomass core-shell bioreactor(CGC@SiO_(2) aerogel) with selective adsorption and degradation properties was developed.The reactor's core is composed of coffee cellulose aerogel,offering a porous framework conducive to microbial colonization while safeguarding microorganisms from adverse external factors.The shell integrates hydrophobic silica enriched with polydimethylsiloxane,which alters the material's hydrophilic properties,enabling it to remain afloat on water for up to 100 days.This superhydrophobic layer maintained a contact angle of 150° even after ten consecutive rubbings.Experimental results indicate that the material performs exceptionally well in oil-water separation,as demonstrated by its success in 9 consecutive oil-water separations.It achieved 99 % selective adsorption,91 % removal,and 46.2 % degradation of a 3 wt.% diesel solution under conditions of 37℃,120 r/min,and pH=7.Additionally,tests assessing environmental tolerance revealed the material's robust adaptability and stability across varying pH levels and temperatures.Compared to traditional hydrophobic and lipophilic materials or free-floating microorganisms,CGC@SiO2 aerogel not only efficiently captures oil pollutants but also degrades them into non-hazardous substances.Combining biodegradation with selective adsorption has shown to be an effective approach for treating oily wastewater,offering significant practical application potential.The low-carbon production of CGC@SiO2aerogel aligns with circular economy principles,underscoring its role in sustainable development.
基金supported by Doctoral Scientific Fund Project of Southwest University of Science and Technology(20zx7130)Seawater Uranium Extraction Innovation and Development Fund Project(China National Nuclear Corporation)(CNNCCXLM-202215)。
文摘Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedstocks,which undoubtedly increases carbon emissions from production in the nuclear industry.Here,a biomass aerogel(CS-BT)is prepared by the facile cross-linking of chitosan and bayberry tannins with glutaraldehyde.U(Ⅵ)can be adsorbed by hydroxyl groups on CS-BT aerogel via chelation,and the maximum adsorption capacity of the obtained aerogel to U(Ⅵ)is 140 mg·g^(-1)and the removal rate reaches up to 99%(at 298.15 K,pH=5.0).The pseudo-second-order kinetics model and Freundlich model can better match the adsorption process of CS-BT aerogel,implying that its adsorption is a chemical adsorption process dominated by multilayer adsorption.The thermodynamic results show that the adsorption process of U(Ⅵ)by CS-BT aerogel is spontaneous and exothermic.Hence,our biomass aerogel can effectively extract uranium from water,contributing to the sustainable development of the nuclear industry.
基金financially supported by the National Natural Science Foundation of China(No.52073294)National Key R&D Program of China(No.2021YFB4000700)+1 种基金Project of Stable Support for Youth Team in Basic Research Field of the Chinese Academy of Sciences,China(No.YSBR-017)The authors are highly grateful to Mr.Fan-Ming Zhao for Cryogenic Mechanical Testing.
文摘With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFC2603500,2022YFC2603502)the Guangzhou Science and Technology Project(No.2024A04J4280).All authors acknowledge the financial support.
文摘Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.
基金supported by the National Natural Science Foundation of China(nos.52130303 and 52327802)the National Key R&D Program of China(no.2022YFB3805702).
文摘As a core technology in flexible electronics systems,piezoresistive sensors exhibit significant application value in frontier fields such as medical health monitoring,intelligent human-machine collaboration,and bionic robot perception.A novel flexible piezoresistive sensing material was developed by combining biomass-derived carbon aerogel(CC)with polydimethylsiloxane(PDMS).The composites had excellent fatigue resistance,maintaining more than 90%shape recovery and less than 3.8%residual deformation after 100000 cycles at 30%strain.Furthermore,combining biomass-derived carbon aerogel with polydimethylsiloxane composites exhibited excellent piezoresistive response characteristics at different temperatures.In the temperature range from-30℃to 100℃,its resistance decreased with increasing temperature,while showing a shortened response time.The composite achieved a stable resistance response through the reversible contact of the conductive network under the action of external forces and had a wide linear detection range,high sensitivity,and effective differentiation between static pressure and dynamic deformation signals.This work established the correlation between the microscopic deformation of the carbon skeleton and the macroscopic electrical behavior,and verified the stability and durability of combining biomass-derived carbon aerogel with polydimethylsiloxane composites under complex stress conditions.The collaborative design strategy provides an innovative platform for the development of sustainable,high-performance flexible sensors with important potential applications in health monitoring and intelligent human-machine interfaces.
基金supported by the National Natural Science Foundation of China(Nos.92371110 and 52373281)Weiqiao Science Foundation(H2872302 and H2872303)the Scientific Research Innovation Capability Support Project for Young Faculty.
文摘Ceramic aerogels(CAs)have emerged as a significant research frontier across various applications due to their lightweight,high porosity,and easily tunable structural characteristics.However,the intrinsic weak interactions among the constituent nanoparticles,coupled with the limited toughness of traditional CAs,make them susceptible to structural collapse or even catastrophic failure when exposed to complex mechanical external forces.Unlike 0D building units,1D ceramic nanofibers(CNFs)possess a high aspect ratio and exceptional flexibility simultaneously,which are desirable building blocks for elastic CAs.This review presents the recent progress in electrospun ceramic nanofibrous aerogels(ECNFAs)that are constructed using ECNFs as building blocks,focusing on the various preparation methods and corresponding structural characteristics,strategies for optimizing mechanical performance,and a wide range of applications.The methods for preparing ECNFs and ECNFAs with diverse structures were initially explored,followed by the implementation of optimization strategies for enhancing ECNFAs,emphasizing the improvement of reinforcing the ECNFs,establishing the bonding effects between ECNFs,and designing the aggregate structures of the aerogels.Moreover,the applications of ECNFAs across various fields are also discussed.Finally,it highlights the existing challenges and potential opportunities for ECNFAs to achieve superior properties and realize promising prospects.
基金supported by ZJNSF LZ25E030006Zhejiang Provincial Key Research and Development Program(2024C01157)+2 种基金NSFC under Grant Nos.52473267 and 52401249the National Key Research and Development Program of China under Grant No.2021YFB3501504Zhejiang University Ningbo“Five in One”Campus Project(K-20213539)。
文摘Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.
基金financially supported by the National Natural Science Foundation of China(Nos.21876164 and U2030203)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘To address the poor mechanical properties of polydimethylsiloxane(PDMS)and enhance the understanding of the reinforcement mechanisms of aerogel network structures in rubber matrices,this study reinforced PDMS using an ordered interconnected three-dimensional montmorillonite(MMT)aerogel network.The average pore diameter of the aerogels was successfully reduced from 11.53μm to 2.51μm by adjusting the ratio of poly(vinyl alcohol)(PVA)to MMT via directional freezing.Changes in the aerogel network were observed in field emission scanning electron microscope(FESEM)images.After vacuum impregnation,the aerogel network structure of the composites was observed using FESEM.Tensile tests indicated that as the pore diameter decreased,the elongation at break of the composites first increased to a peak of329.61%before decreasing,while the tensile strength and Young's modulus continuously increased to their maximum values of 6.29 MPa and24.67 MPa,respectively.Meanwhile,FESEM images of the tensile cracks and fracture surfaces showed that with a reduction in aerogel pore diameter,the degrees of crack deflection and interfacial debonding increased,presenting a rougher fracture surface.These phenomena enable the composites to dissipate substantial energy during tension,thus effectively improving the mechanical strength of the composites.The present work elucidates the bearing of ordered three-dimensional aerogel network structures on the performance of rubber matrices and provides crucial theoretical insights and technical guidance for the creation and optimization of high-performance PDMS-based composites.
基金sponsored by National Natural Science Foundation of China(No.52302121,No.52203386)Shanghai Sailing Program(No.23YF1454700)+1 种基金Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664).
文摘With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.
基金supported by the National Natural Science Foun-dation of China(Grant No.U2167214).
文摘Due to excellent thermal insulation performance at room temperature and ultralow density,silica aero-gels are candidates for thermal insulation.However,at high temperatures,the thermal insulation prop-erty of silica aerogels decreased greatly caused by transparency to heat radiation.Opacifiers introduced into silica sol can block heat radiation yet destroy the uniformity of aerogels.Herein,we designed and prepared a silica aerogel composite with oriented and layered silica fibers(SFs),SiC nanowires(SiC_(NWs)),and silica aerogels,which were prepared by papermaking,chemical vapor infiltration(CVI),and sol-gel respectively.Firstly,oriented and layered SFs made still air a wall to block heat transfer by the solid phase.Secondly,SiC_(NWs) were grown in situ on the surface of SFs evenly to weave into the network,and the network reduced the gaseous thermal conductivity by dividing cracks in SFs/SiC_(NWs)/SA.Thirdly,SiC_(NWs) weakened the heat transfer by radiation at high temperatures.Therefore,SFs/SiC_(NWs)/SA presented remarkable thermal insulation(0.017 W(m K)^(-1) at 25℃,0.0287 W(m K)^(-1) at 500℃,and 0.094 W(m K)^(-1) at 1000℃).Besides,SFs/SiC_(NWs)/SA exhibited remarkable thermal stability(no size transform after being heat treated at 1000℃ for 1800 s)and tensile strength(0.75 MPa).These integrated properties made SFs/SiC_(NWs)/SA a promising candidate for highly efficient thermal insulators.
基金supported by the Key Projects of Intergovernmental International Cooperation in the Key R&D programs of the Ministry of Science and Technology of China(No.2021YFE0115800)the National Science Funding Committee of China(No.U20A20250)+1 种基金the Programs of the Science and Technology of Yulin City(No.CXY-2023-ZX04)the funding support from Shccig-Qinling Program.
文摘Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abundant surface defects are considered to be excellent substrate materials for reducing Pt agglomeration and enhancing catalytic activity.Herein,Pt-based GA composites(Pt-GA-x)featuring homogeneous particle dispersion and high activity were successfully synthesized through a one-step reduction method.Fourier transform infrared(FTIR),Raman,and X-ray photoelectron spectroscopy(XPS)test results indicate that the presence of a large number of oxygen-containing functionalities in GA for anchoring Pt NPs,and the interaction with GA produces electronically structured Pt and defect-rich GA substrates.The obtained electrocatalyst Pt-GA-2 possesses a large specific surface area(443.46 m^(2)·g^(−1)),low Pt loading(3.08 wt%),and uniformly dispersed Pt NPs(average 42 nm).As an advanced hydrogen evolution reaction(HER)electrocatalyst,an overpotential of 34 mV is achieved at a current density of 10 mA·cm^(−2)in 0.5 M H_(2)SO_(4)electrolyte,together with a low Tafel slope of 33.2 mV·dec^(−1).Hence,high mass activity(5623 mA·mgPt^(−1))and turnover frequency(TOF=2.57 s^(−1)at η=100 mV)can be obtained,which are 6.81 and 6.76 times higher than those of commercial Pt/C catalysts.All these are attributed to enormous surface defects over GA and electron enrichment on Pt NPs.The present study highlights the unique advantages of GA in electrochemical energy conversion and provides new avenues to fabricate advanced HER electrocatalysts.
基金supported by the National Natural Science Foundation of China(No.52233003)the Department of Sichuan Province(No.2022JDJQ0023)。
文摘As the application scenarios of aerogels expand,higher requirements are put forward for the materials used to prepare aerogels.Due to the unique chemical structure,polytetrafluoroethylene(PTFE)has excellent properties such as high-temperature resistance,hydrophobicity,and chemical stability.However,the PTFE aerogels are difficult to be molded due to the weak interaction between resin particles.In this work,poly(ethylene oxide)(PEO)was selected as the carrier to assist the PTFE aerogels molding.The pure PTFE aerogels were prepared by homogeneously mixing PTFE aqueous dispersion and PEO,freeze-drying,and high-temperature sintering.When the mass fraction of PTFE and PEO were appropriate,the porosity of PTFE aerogels exceeded 90%and had a hierarchical honeycomb structure.Results showed that the PTFE aerogels not only had excellent hydrophobicity but also possessed superior acoustic insulation,mechanical strength,thermal insulation,and heat resistance properties.Specifically,the water contact angle is about 140°.The noise reduction coefficient is 0.34 and the average sound absorption coefficient is greater than 88%in the frequency range of 2000-6400 Hz.Meanwhile,the thermal conductivity in the air is about 0.045 W/(m·K),and the initial thermal decomposition temperature is 450℃.More importantly,the PTFE aerogels had excellent temperature and corrosion resistance.Even after extremely thermal and chemical treatment,they remained unchanged porous structure as well as acoustic and thermal insulation properties,which exhibits great potential for application in many harsh environments.
基金the financial support provided by the National Natural Science Foundation of China(Nos.22175094,21971113)。
文摘Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreover,due to the accumulation of COFs nanoparticles,it is not conducive to the full utilization of their surface functional groups.Currently,the strategy of COFs assembling into aerogel can be a good solution to this problem.Herein,we successfully synthesize composite aerogels(CSR)by in-situ self-assembly of two-dimensional COFs and graphene based on crosslinking of sodium alginate.Sodium alginate in the composite improves the mechanical properties of the aerogel,and graphene provides a template for the in-situ growth of COFs.Impressively,CSR aerogels with different COFs and sizes can be prepared by changing the moiety of the ligand and modulating the addition amount of COFs.The prepared CSR aerogels exhibit porous,low density,good processability and good mechanical properties.Among them,the density of CSR-N-1.6 is only 5 mg/cm3,which is the lowest density among the reported COF aerogels so far.Due to these remarkable properties,CSR aerogels perform excellent adsorption and recycling properties for the efficient and rapid removal of organic pollutants(organic dyes and antibiotics)from polluted water.In addition,it is also possible to visually recognize the presence of antibiotics by fluorescence detection.This work not only provides a new strategy for synthesizing COF aerogels,but also accelerates the practical application of COF aerogels and contributes to environmental remediation.
基金supported by the Natural Science Foundation of Hunan Province(No.2024JJ5419)the Hunan Provincial Key Research and Development Plan Project in 2024(No.2024JK2074)+1 种基金the Natural Science Foundation of Changsha(No.2023-197)the Open project of the Key Laboratory of digital flavor research of Hunan China Tobacco Industry Co.,Ltd(No.202143000834024).
文摘Multifunctional compatible stealth materials have emerged as the focal point of contemporary protection technology research and vanadium-based nanomaterials play a pivotal role in the development of advanced stealth materials.Here,a compatible stealth aerogel is successfully synthesized by employing mixed-valence decavanadate as the vanadium oxide(VO_(x))molecular model.Ultralight{V^(Ⅳ)VV_(9)}/MXene aerogel(0.0429 g cm^(-3))exhibits exceptional radar stealth performance with a minimal reflection loss(RL_(min))of−57.74 dB(99.9998%EMW absorption)and a significantly superior radar cross section reduction value of 26.77 dB m2.The aerogel’s exceptional properties,including a low infrared(IR)emissivity(0.479)and a low thermal conductivity of(32.30 mW m^(-1)K^(-1)),are crucial for enabling compatibility with IR and thermal stealth technologies.The presence of a mixed-valence polyoxovanadate cluster leads to an increase in the Schottky barrier and enhances magnetic properties,consequently boosting interfacial polarization and contributing to magnetic losses during electromagnetic wave(EMW)absorption.Consequently,altering the number of valence electrons significantly enhances the compatible stealth capabilities.These findings contribute significantly to our comprehension of how microstructure impacts EMW absorption processes and provide a basis for further research into the development of VO_(x)-based compatible stealth materials.
