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
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
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{VⅣVV_(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
Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density...Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density functional theory(DFT)calculations were performed at first to study the d–d orbital interaction of metallic Pt Pd Cu,revealing that the incorporation of Pd and Cu atoms into Pt system can enhance d-d electron interaction via capturing antibonding orbital electrons of Pt to fill the surrounding Pd and Cu atoms.Under the theoretical guidance,Pt Pd Cu medium entropy alloy aerogels(Pt Pd Cu MEAAs)catalysts have been designed and systematically screened for MOR under acid,alkaline and neutral electrolyte.Furthermore,DFT calculation and in-situ fourier transform infrared spectroscopy analysis indicate that Pt Pd Cu MEAAs follow the direct pathway via formate as the reactive intermediate to be directly oxidized to CO_(2).For practical direct methanol fuel cells(DMFCs),the Pt Pd Cu MEAAs-integrated ultra-thin catalyst layer(4–5μm thickness)as anode exhibits higher peak power density of 35 m W/cm^(2) than commercial Pt/C of 20 m W/cm^(2)(~40μm thickness)under the similar noble metal loading and an impressive stability retention at a 50-m A/cm^(2) constant current for 10 h.This work clearly proves that optimizing the intermediate adsorption capacity via d-d orbital coupling is an effective strategy to design highly efficient catalysts for DMFCs.展开更多
Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aeroge...Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aerogels(CAs)have become a highly promising candidate due to their unique three-dimensional porous structure,low density,high specific surface area,biodegradability and easy functionalization.Inspiration from the material and structural designs of natural biological systems has also effectively promoted the development and multifunctional applications of high-performance aerogels,positioning cellulose aerogels as a key area of research in the field of water treatment.This review systematically summarizes recent advancements in the design and functionalization strategies of cellulose aerogels specifically tailored for water pollution treatment.Firstly,it provides a comprehensive overview of CAs classification(native,regenerated,derivative,and composite),principal preparation methodologies including sol-gel processes and drying techniques(supercritical,freeze,and ambient pressure drying),and crucial functionalization approaches(such as surface chemical modification,incorporation of functional materials,and biomimetic structural design.).Subsequently,the review elaborates on the diverse applications of functionalized CAs in tackling various water contaminants,including efficient oil-water separation,removal of heavy metal ions,adsorption of organic dyes,treatment of emerging pollutants like microplastics,and solar-driven water desalination.The underlying pollutant removal mechanisms are analyzed in depth,encompassing physical adsorption,size sieving,interfacial wettability control,electrostatic interactions,coordination/ion exchange,photothermal conversion,catalytic degradation,and synergistic effects.This review provides insights for developing advanced cellulose-based aerogels,while highlighting current challenges and future perspectives in water treatment.展开更多
Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution an...Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.展开更多
Considering the challenges posed by severe electromagnetic wave pollution and escalating international tensions,there is a critical need to develop advanced electromagnetic wave absorbing(EMWA)materials that integrate...Considering the challenges posed by severe electromagnetic wave pollution and escalating international tensions,there is a critical need to develop advanced electromagnetic wave absorbing(EMWA)materials that integrate radar stealth and thermal insulation capabilities.In this study,we have synthesized three-dimensional(3D)porous composites comprising V_(2)O_(3) nanoparticles embedded in Juncus effusus cellulose-derived carbon aerogels(VCA)using a self-templating method followed by high-temperature pyrolysis.The V_(2)O_(3) nanoparticles possess a 3D V-V framework and a relatively narrow bandgap,facilitating the Mott transition for enhanced conductivity.Furthermore,their uniform dispersion on hollow carbon tubes of Juncus effusus promotes efficient electron transfer and creates numerous heterogeneous interfaces.Consequently,VCA-2 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.92 dB at a matching thickness of 2.0mm and a maximum effective absorption bandwidth of 8.24 GHz at a thickness of 2.44mm,covering nearly half of the tested frequency range.Additionally,the radar cross-section reduction reaches a peak value of 29.40 dB m^(2),underscoring the excellent radar stealth capabilities of the material.In summary,VCA exhibits exceptional EMWA,radar stealth,and thermal insulation properties,highlighting its potential for multifunctional applications in EMWA material development.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
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
Monolithic aerogels are promising candidates for use in atmospheric environmental purification due to their structural advantages,such as fine building block size together with high specific surface area,abundant pore...Monolithic aerogels are promising candidates for use in atmospheric environmental purification due to their structural advantages,such as fine building block size together with high specific surface area,abundant pore structure,etc.Additionally,monolithic aerogels possess a unique monolithic macrostructure that sets them apart from aerogel powders and nanoparticles in practical environmental clean-up applications.This review delves into the available synthesis strategies and atmospheric environmental applications of monolithic aerogels,covering types of monolithic aerogels including SiO_(2),graphene,metal oxides and their combinations,along with their preparation methods.In particular,recent developments for VOC adsorption,CO_(2)capture,catalytic oxidation of VOCs and catalytic reduction of CO_(2)are highlighted.Finally,challenges and future opportunities for monolithic aerogels in the atmospheric environmental purification field are proposed.This reviewprovides valuable insights for designing and utilizing monolithic aerogel-based functional materials.展开更多
Integrating phase change materials(PCM)into thermal insulation materials offers a novel approach to aerospace thermal protection.Herein,we used waste biomass as a template;by selecting the appropriate carbonization te...Integrating phase change materials(PCM)into thermal insulation materials offers a novel approach to aerospace thermal protection.Herein,we used waste biomass as a template;by selecting the appropriate carbonization temperature,we obtained carbon aerogels(CCA)with extremely high porosity(95.8%)and high pore volume.After encapsulating PEG2000,we achieved high enthalpy(137.79 J g^(−1),91%of pure PEG2000)and low thermal conductivity(0.137 W(m·K)^(–1),45%of pure PEG2000).Thanks to the rich hierarchical nano-micro porous structure of CCA and the high latent heat of PEG2000,CCA/PEG exhibits excellent thermal insulation properties(under a heating temperature of 131℃,the material takes 1400 s to reach its maximum temperature and can be maintained below 65℃)and cycle performance.Additionally,irradiation destroyed the structure of CCA/PEG,leading to the degradation of PEG and the formation of other carbonyl-containing compounds,which decreased its latent heat(4.2%)and thermal conductivity(16.1%).However,the irradiation-resistant CCA,acting as a protective layer,minimizes the impact of irradiation on PEG2000.Instead,irradiation enhances the hierarchical porous structure of the material,ultimately improving its thermal insulation performance.CCA/PEG has potential application prospects in thermal protection and aerospace and is a strong competitor for high-efficiency thermal insulation materials.展开更多
It is well known that adsorbent material is the key to determine the CO_(2)adsorption performance.Herein,ZIF-8 derived porous carbon(ZIF-8-C)is anchored into the framework of a novel composite aerogel(ZCPx),which util...It is well known that adsorbent material is the key to determine the CO_(2)adsorption performance.Herein,ZIF-8 derived porous carbon(ZIF-8-C)is anchored into the framework of a novel composite aerogel(ZCPx),which utilizes chitosan(CS)and polyvinyl alcohol(PVA)as raw materials.By controlling the ratio of ZIF-8-C,the developed hierarchical porous structures combine the advantages of micropores,mesopores,and macropores.Besides,the ligand material of ZIF-8-C and the amino group from CS are two sources of the high nitrogen content of ZCPx.The optimized sample ZCP4 shows a high nitrogen content of 6.78%,which can create more active centers and supply basic sites,thereby enhancing the CO_(2)adsorption capacity.Moreover,ZC P4 composite aerogel presents a CO_(2)adsorption capacity of2.26 mmol·g^(-1)(298 K,0.1 MPa)and CO_(2)/N_(2)selectivity(S_(CO_(2))/N_(2))can reach 20.02,and the dynamic breakthrough experiment is performed to confirm the feasibility of CO_(2)/N_(2)actual separation performance,proving that the composite aerogel is potential candidates for CO_(2)adsorption.展开更多
To optimize the preparation of alumina aerogels,the sol-gel method was combined with supercritical drying,using aluminum isopropoxide(AIP)as the precursor,ethanol(EtOH)as the solvent,and acetic acid(HAc)as the catalys...To optimize the preparation of alumina aerogels,the sol-gel method was combined with supercritical drying,using aluminum isopropoxide(AIP)as the precursor,ethanol(EtOH)as the solvent,and acetic acid(HAc)as the catalyst.The effects of the ethanol addition[n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:8:0.8:2,1:12:0.8:2,1:16:0.8:2,and 1:20:0.8:2]and acetic acid addition[n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:16:0.8:1,1:16:0.8:2,1:16:0.8:3,and 1:16:0.8:4]on the pore structure and specific surface area of Al_(2)O_(3) aerogels were studied.The results show that ethanol affects the pore structure of Al_(2)O_(3) aerogels by affecting the condensation probability of Al-OH troups,and acetic acid affects the pore structure of Al_(2)O_(3) aerogels by affecting the reaction rate;when n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:16:0.8:2,the Al_(2)O_(3) aerogel has a porous microstructure,and its internal pore diameters is generally smaller than the average free path of air molecules,showing excellent thermal insulation characteristics,low density of 0.20 g·cm^(-3),and the specific surface areas of 458,102,and 51 m^(2)·g^(-1) at 25,1000,and 1200℃,respectively.展开更多
Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages...Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.展开更多
Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying un...Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down to 2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.展开更多
A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The struct...A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.展开更多
Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers,the resulting nanocomposites usually exhibit low through-plane thermal conductivities,limiting their...Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers,the resulting nanocomposites usually exhibit low through-plane thermal conductivities,limiting their application as thermal interface materials.Herein,lamellarstructured polyamic acid salt/graphene oxide(PAAS/GO)hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by lyophilization.Subsequently,PAAS monomers are polymerized to polyimide(PI),while GO is converted to thermally reduced graphene oxide(RGO)during thermal annealing at 300℃.Final graphitization at 2800℃ converts PI to graphitized carbon with the inductive effect of RGO,and simultaneously,RGO is thermally reduced and healed to high-quality graphene.Consequently,lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time,and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene lamellae.After vacuum-assisted impregnation with epoxy,the resultant epoxy composite with 2.30 vol% of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m^−1 K^−1,100 times of that of epoxy,with a record-high specific thermal conductivity enhancement of 4310%.Furthermore,the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness,~1.71 times of that of epoxy.展开更多
Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for...Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for assisting in building conductive,hyperelastic,and ultralight Ti_(3)C_(2)T_(x)MXene hybrid aerogels with oriented tracheid-like texture.The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF,carbon nanotube(CNT),and MXene based on synergistic electrostatic interaction and hydrogen bonding.Entangled CNF and CNT“mortars”bonded with MXene“bricks”of the tracheid structure produce good interfacial binding,and superior mechanical strength(up to 80%compressibility and extraordinary fatigue resistance of 1000 cycles at 50%strain).Benefiting from the biomimetic texture,CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm^(-3)and excellent electrical conductivity(~2400 S m^(-1)).Used as pressure sensors,such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa^(-1),which affords their application in monitoring body surface information and detecting human motion.Furthermore,the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance(849.2 mF cm^(-2)at 0.8 mA cm^(-2))and superior long cycle compression performance(88%after 10,000 cycles at a compressive strain of 30%).展开更多
Recently,multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials.Nevertheless,excessive stack and agglomeration for low-dimension carbon nanomaterials inducing imped...Recently,multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials.Nevertheless,excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges.Herein,the delicate“3D helix-2D sheet-1D fiber-0D dot”hierarchical aerogels have been successfully synthesized,for the first time,by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method.Particularly,the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils,which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties.Moreover,by adjusting the content of 0D core-shell structured particles and the parameters for growth of the 1D carbon nanofibers,tunable electromagnetic properties and excellent impedance matching are achieved,which plays a vital role in the microwave absorption performance.As expected,the optimized aerogels harvest excellent performance,including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness.This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures,which holds great application potential for electromagnetic wave attenuation.展开更多
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)+2 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)the Recruitment Program of Global Youth Experts.The authors also thank Shiyanjia Lab(www.shiyanjia.com)for the support of the UPS test.
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{VⅣVV_(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.
基金financially supported by the National Natural Science Foundation of China(Nos.52073214 and 22075211)Guangxi Natural Science Fund for Distinguished Young Scholars(No.2024GXNSFFA010008)+5 种基金Natural Science Foundation of Shandong Province(Nos.ZR2023MB049 and ZR2021QB129)China Postdoctoral Science Foundation(No.2020M670483)Science Foundation of Weifang University(No.2023BS11)supported by the open research fund of the Laboratory of Xinjiang Native Medicinal and Edible Plant Resources Chemistry at Kashi Universitysupported by the Tianhe Qingsuo Open Research Fund of TSYS in 2022 and NSCC-TJNankai University Large-scale Instrument Experimental Technology R&D Project(No.21NKSYJS09)。
文摘Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction(MOR)performance can fundamentally guide high efficient catalyst design.Herein,density functional theory(DFT)calculations were performed at first to study the d–d orbital interaction of metallic Pt Pd Cu,revealing that the incorporation of Pd and Cu atoms into Pt system can enhance d-d electron interaction via capturing antibonding orbital electrons of Pt to fill the surrounding Pd and Cu atoms.Under the theoretical guidance,Pt Pd Cu medium entropy alloy aerogels(Pt Pd Cu MEAAs)catalysts have been designed and systematically screened for MOR under acid,alkaline and neutral electrolyte.Furthermore,DFT calculation and in-situ fourier transform infrared spectroscopy analysis indicate that Pt Pd Cu MEAAs follow the direct pathway via formate as the reactive intermediate to be directly oxidized to CO_(2).For practical direct methanol fuel cells(DMFCs),the Pt Pd Cu MEAAs-integrated ultra-thin catalyst layer(4–5μm thickness)as anode exhibits higher peak power density of 35 m W/cm^(2) than commercial Pt/C of 20 m W/cm^(2)(~40μm thickness)under the similar noble metal loading and an impressive stability retention at a 50-m A/cm^(2) constant current for 10 h.This work clearly proves that optimizing the intermediate adsorption capacity via d-d orbital coupling is an effective strategy to design highly efficient catalysts for DMFCs.
基金the National Natural Science Foundation of China(No.52105297,U22A20183)the Key Program for International Science and Technology Cooperation Projects of China(2024YFE0105500)+1 种基金Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)JLU Science and Technology Innovative Research Team(No.2020TD-03).
文摘Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aerogels(CAs)have become a highly promising candidate due to their unique three-dimensional porous structure,low density,high specific surface area,biodegradability and easy functionalization.Inspiration from the material and structural designs of natural biological systems has also effectively promoted the development and multifunctional applications of high-performance aerogels,positioning cellulose aerogels as a key area of research in the field of water treatment.This review systematically summarizes recent advancements in the design and functionalization strategies of cellulose aerogels specifically tailored for water pollution treatment.Firstly,it provides a comprehensive overview of CAs classification(native,regenerated,derivative,and composite),principal preparation methodologies including sol-gel processes and drying techniques(supercritical,freeze,and ambient pressure drying),and crucial functionalization approaches(such as surface chemical modification,incorporation of functional materials,and biomimetic structural design.).Subsequently,the review elaborates on the diverse applications of functionalized CAs in tackling various water contaminants,including efficient oil-water separation,removal of heavy metal ions,adsorption of organic dyes,treatment of emerging pollutants like microplastics,and solar-driven water desalination.The underlying pollutant removal mechanisms are analyzed in depth,encompassing physical adsorption,size sieving,interfacial wettability control,electrostatic interactions,coordination/ion exchange,photothermal conversion,catalytic degradation,and synergistic effects.This review provides insights for developing advanced cellulose-based aerogels,while highlighting current challenges and future perspectives in water treatment.
基金the National Natural Science Foundation of China(52090034,52273064,52221006)the Fundamental Research Funds for the Central Universities(JD2417)is gratefully acknowledged.
文摘Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.
基金supported by the National Natural Science Foundation of China(No.22265021)the Aeronautical Science Foundation of China(No.2020Z056056003)。
文摘Considering the challenges posed by severe electromagnetic wave pollution and escalating international tensions,there is a critical need to develop advanced electromagnetic wave absorbing(EMWA)materials that integrate radar stealth and thermal insulation capabilities.In this study,we have synthesized three-dimensional(3D)porous composites comprising V_(2)O_(3) nanoparticles embedded in Juncus effusus cellulose-derived carbon aerogels(VCA)using a self-templating method followed by high-temperature pyrolysis.The V_(2)O_(3) nanoparticles possess a 3D V-V framework and a relatively narrow bandgap,facilitating the Mott transition for enhanced conductivity.Furthermore,their uniform dispersion on hollow carbon tubes of Juncus effusus promotes efficient electron transfer and creates numerous heterogeneous interfaces.Consequently,VCA-2 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.92 dB at a matching thickness of 2.0mm and a maximum effective absorption bandwidth of 8.24 GHz at a thickness of 2.44mm,covering nearly half of the tested frequency range.Additionally,the radar cross-section reduction reaches a peak value of 29.40 dB m^(2),underscoring the excellent radar stealth capabilities of the material.In summary,VCA exhibits exceptional EMWA,radar stealth,and thermal insulation properties,highlighting its potential for multifunctional applications in EMWA material development.
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 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supported by the National Key R&D Program of China(No.2022YFC3702800).
文摘Monolithic aerogels are promising candidates for use in atmospheric environmental purification due to their structural advantages,such as fine building block size together with high specific surface area,abundant pore structure,etc.Additionally,monolithic aerogels possess a unique monolithic macrostructure that sets them apart from aerogel powders and nanoparticles in practical environmental clean-up applications.This review delves into the available synthesis strategies and atmospheric environmental applications of monolithic aerogels,covering types of monolithic aerogels including SiO_(2),graphene,metal oxides and their combinations,along with their preparation methods.In particular,recent developments for VOC adsorption,CO_(2)capture,catalytic oxidation of VOCs and catalytic reduction of CO_(2)are highlighted.Finally,challenges and future opportunities for monolithic aerogels in the atmospheric environmental purification field are proposed.This reviewprovides valuable insights for designing and utilizing monolithic aerogel-based functional materials.
基金funded by the National Natural Science Foundation of China(No.52236006,No.52176054)the Natural Science Foundation of Guangdong province(2024A1515012033).
文摘Integrating phase change materials(PCM)into thermal insulation materials offers a novel approach to aerospace thermal protection.Herein,we used waste biomass as a template;by selecting the appropriate carbonization temperature,we obtained carbon aerogels(CCA)with extremely high porosity(95.8%)and high pore volume.After encapsulating PEG2000,we achieved high enthalpy(137.79 J g^(−1),91%of pure PEG2000)and low thermal conductivity(0.137 W(m·K)^(–1),45%of pure PEG2000).Thanks to the rich hierarchical nano-micro porous structure of CCA and the high latent heat of PEG2000,CCA/PEG exhibits excellent thermal insulation properties(under a heating temperature of 131℃,the material takes 1400 s to reach its maximum temperature and can be maintained below 65℃)and cycle performance.Additionally,irradiation destroyed the structure of CCA/PEG,leading to the degradation of PEG and the formation of other carbonyl-containing compounds,which decreased its latent heat(4.2%)and thermal conductivity(16.1%).However,the irradiation-resistant CCA,acting as a protective layer,minimizes the impact of irradiation on PEG2000.Instead,irradiation enhances the hierarchical porous structure of the material,ultimately improving its thermal insulation performance.CCA/PEG has potential application prospects in thermal protection and aerospace and is a strong competitor for high-efficiency thermal insulation materials.
基金supported by the Natural Science Foundation of Shandong Province(ZR2021ME124,ZR2023ME033)Science-Education-Industry Integration Innovation Pilot Project of Qilu University of Technology(2024GH09)+2 种基金Innovation Capacity Improvement Project of Small and Medium-Sized Technology-Based Enterprise of Shandong Province(2023TSGC0706,2022TSGC1022)Technological Innovation Projects of Shandong Province(202350700179,202351600213)Science and technology plan project of Shandong Railway Investment Holding Group(TTKJ2023-01)。
文摘It is well known that adsorbent material is the key to determine the CO_(2)adsorption performance.Herein,ZIF-8 derived porous carbon(ZIF-8-C)is anchored into the framework of a novel composite aerogel(ZCPx),which utilizes chitosan(CS)and polyvinyl alcohol(PVA)as raw materials.By controlling the ratio of ZIF-8-C,the developed hierarchical porous structures combine the advantages of micropores,mesopores,and macropores.Besides,the ligand material of ZIF-8-C and the amino group from CS are two sources of the high nitrogen content of ZCPx.The optimized sample ZCP4 shows a high nitrogen content of 6.78%,which can create more active centers and supply basic sites,thereby enhancing the CO_(2)adsorption capacity.Moreover,ZC P4 composite aerogel presents a CO_(2)adsorption capacity of2.26 mmol·g^(-1)(298 K,0.1 MPa)and CO_(2)/N_(2)selectivity(S_(CO_(2))/N_(2))can reach 20.02,and the dynamic breakthrough experiment is performed to confirm the feasibility of CO_(2)/N_(2)actual separation performance,proving that the composite aerogel is potential candidates for CO_(2)adsorption.
文摘To optimize the preparation of alumina aerogels,the sol-gel method was combined with supercritical drying,using aluminum isopropoxide(AIP)as the precursor,ethanol(EtOH)as the solvent,and acetic acid(HAc)as the catalyst.The effects of the ethanol addition[n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:8:0.8:2,1:12:0.8:2,1:16:0.8:2,and 1:20:0.8:2]and acetic acid addition[n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:16:0.8:1,1:16:0.8:2,1:16:0.8:3,and 1:16:0.8:4]on the pore structure and specific surface area of Al_(2)O_(3) aerogels were studied.The results show that ethanol affects the pore structure of Al_(2)O_(3) aerogels by affecting the condensation probability of Al-OH troups,and acetic acid affects the pore structure of Al_(2)O_(3) aerogels by affecting the reaction rate;when n(AIP):n(EtOH):n(H_(2)O):n(HAc)=1:16:0.8:2,the Al_(2)O_(3) aerogel has a porous microstructure,and its internal pore diameters is generally smaller than the average free path of air molecules,showing excellent thermal insulation characteristics,low density of 0.20 g·cm^(-3),and the specific surface areas of 458,102,and 51 m^(2)·g^(-1) at 25,1000,and 1200℃,respectively.
基金supported by the National Nature Science Foundation of China(No.62122030,62333008,62371205,52103208)National Key Research and Development Program of China(No.2021YFB3201300)+1 种基金Application and Basic Research of Jilin Province(20130102010 JC)Fundamental Research Funds for the Central Universities,Jilin Provincial Science and Technology Development Program(20230101072JC)。
文摘Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.
基金This project was financially supported by a grant from the NITECH 21st Century COE Program, "World Ceramics Center for Environmental Harmony".
文摘Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down to 2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.
基金supported by the National Natural Science Foundation of China(21377018)the Natural Science Foundation of Liaoning Province of China(2013020116)the Fundamental Research Funds for the Central Universities(DUT15ZD240)~~
文摘A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.
基金Financial support from the National Natural Science Foundation of China(51773008,51533001,U1905217)the National Key Research and Development Program of China(2016YFC0801302)is gratefully acknowledged.
文摘Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers,the resulting nanocomposites usually exhibit low through-plane thermal conductivities,limiting their application as thermal interface materials.Herein,lamellarstructured polyamic acid salt/graphene oxide(PAAS/GO)hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by lyophilization.Subsequently,PAAS monomers are polymerized to polyimide(PI),while GO is converted to thermally reduced graphene oxide(RGO)during thermal annealing at 300℃.Final graphitization at 2800℃ converts PI to graphitized carbon with the inductive effect of RGO,and simultaneously,RGO is thermally reduced and healed to high-quality graphene.Consequently,lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time,and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene lamellae.After vacuum-assisted impregnation with epoxy,the resultant epoxy composite with 2.30 vol% of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m^−1 K^−1,100 times of that of epoxy,with a record-high specific thermal conductivity enhancement of 4310%.Furthermore,the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness,~1.71 times of that of epoxy.
基金supported by the Project of Jinan City(202228044)National Natural Science Foundation of China(32071720,32271814)+1 种基金the China Postdoctoral Science Foundation(2021M702456)China Scholarship Council for supporting their PhD program。
文摘Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for assisting in building conductive,hyperelastic,and ultralight Ti_(3)C_(2)T_(x)MXene hybrid aerogels with oriented tracheid-like texture.The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF,carbon nanotube(CNT),and MXene based on synergistic electrostatic interaction and hydrogen bonding.Entangled CNF and CNT“mortars”bonded with MXene“bricks”of the tracheid structure produce good interfacial binding,and superior mechanical strength(up to 80%compressibility and extraordinary fatigue resistance of 1000 cycles at 50%strain).Benefiting from the biomimetic texture,CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm^(-3)and excellent electrical conductivity(~2400 S m^(-1)).Used as pressure sensors,such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa^(-1),which affords their application in monitoring body surface information and detecting human motion.Furthermore,the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance(849.2 mF cm^(-2)at 0.8 mA cm^(-2))and superior long cycle compression performance(88%after 10,000 cycles at a compressive strain of 30%).
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51972039,51803018,and 51661145025)LiaoNing Revitalization Talents Program(No.XLYC1902122).
文摘Recently,multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials.Nevertheless,excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges.Herein,the delicate“3D helix-2D sheet-1D fiber-0D dot”hierarchical aerogels have been successfully synthesized,for the first time,by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method.Particularly,the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils,which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties.Moreover,by adjusting the content of 0D core-shell structured particles and the parameters for growth of the 1D carbon nanofibers,tunable electromagnetic properties and excellent impedance matching are achieved,which plays a vital role in the microwave absorption performance.As expected,the optimized aerogels harvest excellent performance,including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness.This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures,which holds great application potential for electromagnetic wave attenuation.
