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
Silver still faces significant challenges in the electrochemical reduction of CO_(2)(eCO_(2)RR)to CO under elevated current density with high energy input due to the intensified hydrogen evolution reaction.The doping ...Silver still faces significant challenges in the electrochemical reduction of CO_(2)(eCO_(2)RR)to CO under elevated current density with high energy input due to the intensified hydrogen evolution reaction.The doping of 2 mol%Re-oxide into Ag aerogel results in a significant decrease in the onset potential and a twofold increase in the current density compared to a pure Ag aerogel(Ag100),which tackles the issue.The effect is rationalized in terms of positively shifting the d-band center close to the Fermi energy level to change the density of local electronic states.Moreover,upon the adsorption of the ionic liquid(IL,1-Allyl-3-methylimidazolium dicyanamide[AMIM][DCN])onto the surface of Re-oxide doped Ag aerogel(Ag_(98)Re_(2)/IL),the current density increases to 320 mA/cm^(2) at a low of-1.3 V vs.RHE with 96%selectivity for CO formation in an alkaline medium using a flow cell electrolyzer,and maintains the selectivity above92%for up to 17 h using an H-cell electrolyzer.Density Functional Theory revealed that the adsorbed IL forms a highly conductive and hydrophobic layer on the aerogel surface,presumably decreasing the local H+concentration,greatly suppressing the hydrogen evolution reaction while enhancing the eCO_(2)RR pathway and mitigating the mass transport issues typically associated with IL use.This work addressed the key challenges in massively producing CO from eCO_(2)RR,offering a promising strategy for scalable and industrial CO generation.展开更多
A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has si...A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has significantly improved oxidation resistance.When the addition amount of Ti_(3)SiC_(2)is 75%,the carbonization volume shrinkage rate of the composite after aerobic static combustion is only 5.95%.At the same time,the LAR and MAR after 30 seconds of oxyacetylene ablation under a heat flux density of 1.5 MW/m2 are 0.0307 mm/s and 0.0149 g/s,respectively.The compressive strength after aerobic static combustion at 1000℃is up to 20.43%of that before aerobic static combustion,which is 1.99 times that of the unfilled material,significantly improving the high-temperature mechanical properties of the composite.展开更多
To improve the thermal insulation performance of SiO_(2)aerogels at high temperatures,SiO_(2)precursor solutions were prepared via a sol-gel two-step method.Fe_(2)O_(3)powder was extra added as an opacifier to the SiO...To improve the thermal insulation performance of SiO_(2)aerogels at high temperatures,SiO_(2)precursor solutions were prepared via a sol-gel two-step method.Fe_(2)O_(3)powder was extra added as an opacifier to the SiO_(2)precursor solutions with mass fractions of 0,0.2%,0.5%,1.0%,and 3.0%;and Fe_(2)O_(3)-SiO_(2)composite aerogels were fabricated using CO_(2)supercritical drying technology.The effects of the Fe_(2)O_(3)extra addition on the aerogels were investigated.The results show that:(1)Fe_(2)O_(3)doping does not alter the aerogel morphology;Fe_(2)O_(3)suppresses the mass loss at high temperatures and enhances the high-temperature stability of the composite;(2)below 800℃,the aerogel with 0.5%Fe_(2)O_(3)exhibits the lowest thermal conductivity and the best thermal insulation performance;at 800-1000℃,the aerogel with 1%Fe_(2)O_(3)exhibits the lowest thermal conductivity and a good nanoporous structure;(3)by adjusting the Fe_(2)O_(3)extra addition,composite aerogels suitable for different temperature ranges can be tailored.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
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
TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XR...TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XRD and so on. The results indicate that the BET surface area of TiO2/SiO2 aerogels calcined at 550℃ which consisted of anatase structure of TiO2 with narrow distribution pores of 5-25 nm is as high as 357.89 m2·g-1. For the photocatalytic degradation of pyridine, the catalytic activities of TiO2/SiO2 aerogels are much higher than that of TiO2 powder. The photocatalytic activity of TiO2/SiO2 aerogels calcined at 800℃ is the optimum. The higher the content of SiO2, the higher the photocatalytic activity of TiO2/SiO2 aerogels. The cost for preparation of the aerogels is greatly reduced by using non-supercritical drying method, and the aerogels are hopefully applied in the treatment of industrial waste water such as coking effluent treatment.展开更多
Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for ...Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.展开更多
One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal charact...One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal characteristics.Electrospinning is a straightforward and versatile method to prepare 1D SNFs with programmable structures,manageable dimensions,and modifiable properties,which hold great potential in many cutting-edge applications including aerospace,nanodevice,and energy.In this review,substantial advances in the structural design,controllable synthesis,and multifunctional applications of electrospun SNFs are highlighted.We begin with a brief introduction to the fundamental principles,available raw materials,and typical apparatus of electrospun SNFs.We then discuss the strategies for preparing SNFs with diverse structures in detail,especially stressing the newly emerging three-dimensional SiO_(2) nanofibrous aerogels.We continue with focus on major breakthroughs about brittleness-to-flexibility transition of SNFs and the means to achieve their mechanical reinforcement.In addition,we showcase recent applications enabled by electrospun SNFs,with particular emphasis on physical protection,health care and water treatment.In the end,we summarize this review and provide some perspectives on the future development direction of electrospun SNFs.展开更多
The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as...The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as modifier, ethanol as solvent. Moreover, the structure and adsorption property of SiO2 aerogels were also studied. As results, the surface area of SiO2 aerogels was 863.59 m2/g, the pore volume was 3.57 cm3/g, and the contact angle was 150 °. Adsorption intensity of silica aerogels for organic liquid （alkanes, benzene compounds, and nitro-compounds） is bigger than that of activated carbon. The mass of the liquid absorbed increased linearly with the surface tension of the liquid. The lower surface tension and boiling point are, the shorter desorption time is. After regenerating 10 times, nitromethane regeneration rate remain the same, and almost more than 94%. So SiO2 aerogels have good absorption and regeneration property.展开更多
Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior micr...Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior microstructure,as well as good compatibility with other electromagnetic(EM)components.Herein,we realized the decoration of rGO aerogel with Mo_(2)C nanoparticles by sequential hydrothermal assembly,freeze-drying,and high-temperature pyrolysis.Results show that Mo_(2)C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio.The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo_(2)C nanoparticles,and more importantly,these nanoparticles regulate the EM properties of the rGO aerogel to a large extent.Although more Mo_(2)C nanoparticles may decrease the overall attenuation ability of the rGO aerogel,they bring much better impedance matching.At a molar ratio of 1:1,a desirable balance between attenuation ability and impedance matching is observed.In this context,the Mo_(2)C/r GO aerogel displays strong reflection loss and broad response bandwidth,even with a small applied thickness(1.7 mm)and low filler loading(9.0wt%).The positive effects of Mo_(2)C nanoparticles on multifunctional properties may render Mo_(2)C/r GO aerogels promising candidates for high-performance EWAMs under harsh conditions.展开更多
Al_(2)O_(3)–SiO_(2)sols were synthesized by using aluminum chloride hex hydrate and tetraethoxysilane(TEOS)as precursors,deionized water and ethanol mixture as the solvent,and propylene oxide as the coagulant aids.Al...Al_(2)O_(3)–SiO_(2)sols were synthesized by using aluminum chloride hex hydrate and tetraethoxysilane(TEOS)as precursors,deionized water and ethanol mixture as the solvent,and propylene oxide as the coagulant aids.Alumina coatings were prepared on the surfaces of hollow quartz filament fiber,then a new lightweight and thermal insulating material were successfully prepared by impregnatingAl_(2)O_(3)–SiO_(2)sol into a needle fabric made by coated hollow quartz filament fiber.The coated quartz fiber,aerogels and composites were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),nitrogen adsorption-desorption(BET),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and tensile tests.The effects of different fiber and calcination temperatures on the microstructures and properties ofAl_(2)O_(3)–SiO_(2)composite aerogels were investigated.The test results indicate that the mechanical properties of the aerogels are improved by introducing quartz filament fabrics and the introduction of alumina coating improves the thermal stability of the material.Compared to other fibers,Al_(2)O_(3)-coated hollow quartz fiber has significant advantages as reinforcement for composite,and their tensile strength is well retained after high temperature heat treatment.展开更多
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.
基金Funding from the Natural Science and Engineering Research Council of Canada(RGPIN-2022-03129)China Scholarship Council(202308210183)the University of Toronto is gratefully acknowledged。
文摘Silver still faces significant challenges in the electrochemical reduction of CO_(2)(eCO_(2)RR)to CO under elevated current density with high energy input due to the intensified hydrogen evolution reaction.The doping of 2 mol%Re-oxide into Ag aerogel results in a significant decrease in the onset potential and a twofold increase in the current density compared to a pure Ag aerogel(Ag100),which tackles the issue.The effect is rationalized in terms of positively shifting the d-band center close to the Fermi energy level to change the density of local electronic states.Moreover,upon the adsorption of the ionic liquid(IL,1-Allyl-3-methylimidazolium dicyanamide[AMIM][DCN])onto the surface of Re-oxide doped Ag aerogel(Ag_(98)Re_(2)/IL),the current density increases to 320 mA/cm^(2) at a low of-1.3 V vs.RHE with 96%selectivity for CO formation in an alkaline medium using a flow cell electrolyzer,and maintains the selectivity above92%for up to 17 h using an H-cell electrolyzer.Density Functional Theory revealed that the adsorbed IL forms a highly conductive and hydrophobic layer on the aerogel surface,presumably decreasing the local H+concentration,greatly suppressing the hydrogen evolution reaction while enhancing the eCO_(2)RR pathway and mitigating the mass transport issues typically associated with IL use.This work addressed the key challenges in massively producing CO from eCO_(2)RR,offering a promising strategy for scalable and industrial CO generation.
基金Funded by by the Wuhan Science and Technology Project(No.2024010702030141)。
文摘A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has significantly improved oxidation resistance.When the addition amount of Ti_(3)SiC_(2)is 75%,the carbonization volume shrinkage rate of the composite after aerobic static combustion is only 5.95%.At the same time,the LAR and MAR after 30 seconds of oxyacetylene ablation under a heat flux density of 1.5 MW/m2 are 0.0307 mm/s and 0.0149 g/s,respectively.The compressive strength after aerobic static combustion at 1000℃is up to 20.43%of that before aerobic static combustion,which is 1.99 times that of the unfilled material,significantly improving the high-temperature mechanical properties of the composite.
文摘To improve the thermal insulation performance of SiO_(2)aerogels at high temperatures,SiO_(2)precursor solutions were prepared via a sol-gel two-step method.Fe_(2)O_(3)powder was extra added as an opacifier to the SiO_(2)precursor solutions with mass fractions of 0,0.2%,0.5%,1.0%,and 3.0%;and Fe_(2)O_(3)-SiO_(2)composite aerogels were fabricated using CO_(2)supercritical drying technology.The effects of the Fe_(2)O_(3)extra addition on the aerogels were investigated.The results show that:(1)Fe_(2)O_(3)doping does not alter the aerogel morphology;Fe_(2)O_(3)suppresses the mass loss at high temperatures and enhances the high-temperature stability of the composite;(2)below 800℃,the aerogel with 0.5%Fe_(2)O_(3)exhibits the lowest thermal conductivity and the best thermal insulation performance;at 800-1000℃,the aerogel with 1%Fe_(2)O_(3)exhibits the lowest thermal conductivity and a good nanoporous structure;(3)by adjusting the Fe_(2)O_(3)extra addition,composite aerogels suitable for different temperature ranges can be tailored.
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Supported by the National Natural Science Foundation of China (No. 20473057)Development Foundation of Science and Technology of Shanghai (No. 0352nm094).
文摘TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XRD and so on. The results indicate that the BET surface area of TiO2/SiO2 aerogels calcined at 550℃ which consisted of anatase structure of TiO2 with narrow distribution pores of 5-25 nm is as high as 357.89 m2·g-1. For the photocatalytic degradation of pyridine, the catalytic activities of TiO2/SiO2 aerogels are much higher than that of TiO2 powder. The photocatalytic activity of TiO2/SiO2 aerogels calcined at 800℃ is the optimum. The higher the content of SiO2, the higher the photocatalytic activity of TiO2/SiO2 aerogels. The cost for preparation of the aerogels is greatly reduced by using non-supercritical drying method, and the aerogels are hopefully applied in the treatment of industrial waste water such as coking effluent treatment.
基金financially supported by the National Natural Science Foundation of China(No.U2004177 and U21A2064)Outstanding Youth Fund of Henan Province(No.212300410081)+1 种基金Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province(22HASTIT001)The Research and Entrepreneurship Start-up Projects for Overseas Returned Talents。
文摘Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.
基金This work was supported by the National Natural Science Foundation of China(Nos.21961132024,51925302,and 52173055)the Ministry of Science and Technology of China(No.2021YFE0105100)the Fundamental Research Funds for the Central Universities and the DHU Distinguished Young Professor Program(No.LZA2020001).
文摘One-dimensional(1D)SiO_(2) nanofibers(SNFs),one of the most popular inorganic nanomaterials,have aroused widespread attention because of their excellent chemical stability,as well as unique optical and thermal characteristics.Electrospinning is a straightforward and versatile method to prepare 1D SNFs with programmable structures,manageable dimensions,and modifiable properties,which hold great potential in many cutting-edge applications including aerospace,nanodevice,and energy.In this review,substantial advances in the structural design,controllable synthesis,and multifunctional applications of electrospun SNFs are highlighted.We begin with a brief introduction to the fundamental principles,available raw materials,and typical apparatus of electrospun SNFs.We then discuss the strategies for preparing SNFs with diverse structures in detail,especially stressing the newly emerging three-dimensional SiO_(2) nanofibrous aerogels.We continue with focus on major breakthroughs about brittleness-to-flexibility transition of SNFs and the means to achieve their mechanical reinforcement.In addition,we showcase recent applications enabled by electrospun SNFs,with particular emphasis on physical protection,health care and water treatment.In the end,we summarize this review and provide some perspectives on the future development direction of electrospun SNFs.
基金Funded by the National Natural Science Foundation of China (No. 10976013)the Science Project of Ministry of Housing and Urban-Rural Development(No. 2011-K7-16)+1 种基金the State Key Laboratory of Materials-Oriented Chemical Engineeringthe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as modifier, ethanol as solvent. Moreover, the structure and adsorption property of SiO2 aerogels were also studied. As results, the surface area of SiO2 aerogels was 863.59 m2/g, the pore volume was 3.57 cm3/g, and the contact angle was 150 °. Adsorption intensity of silica aerogels for organic liquid （alkanes, benzene compounds, and nitro-compounds） is bigger than that of activated carbon. The mass of the liquid absorbed increased linearly with the surface tension of the liquid. The lower surface tension and boiling point are, the shorter desorption time is. After regenerating 10 times, nitromethane regeneration rate remain the same, and almost more than 94%. So SiO2 aerogels have good absorption and regeneration property.
基金supported by the China Postdoctoral Science Foundation(No.2021MD703944)the Fund of Science and Technology on Near-Surface Detection Laboratory(No.6142414211808)+1 种基金the Director Fund of State Key Laboratory of Pulsed Power Laser Technology(No.SKL2021ZR06)the National Natural Science Foundation of China(No.21776053)。
文摘Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior microstructure,as well as good compatibility with other electromagnetic(EM)components.Herein,we realized the decoration of rGO aerogel with Mo_(2)C nanoparticles by sequential hydrothermal assembly,freeze-drying,and high-temperature pyrolysis.Results show that Mo_(2)C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio.The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo_(2)C nanoparticles,and more importantly,these nanoparticles regulate the EM properties of the rGO aerogel to a large extent.Although more Mo_(2)C nanoparticles may decrease the overall attenuation ability of the rGO aerogel,they bring much better impedance matching.At a molar ratio of 1:1,a desirable balance between attenuation ability and impedance matching is observed.In this context,the Mo_(2)C/r GO aerogel displays strong reflection loss and broad response bandwidth,even with a small applied thickness(1.7 mm)and low filler loading(9.0wt%).The positive effects of Mo_(2)C nanoparticles on multifunctional properties may render Mo_(2)C/r GO aerogels promising candidates for high-performance EWAMs under harsh conditions.
文摘Al_(2)O_(3)–SiO_(2)sols were synthesized by using aluminum chloride hex hydrate and tetraethoxysilane(TEOS)as precursors,deionized water and ethanol mixture as the solvent,and propylene oxide as the coagulant aids.Alumina coatings were prepared on the surfaces of hollow quartz filament fiber,then a new lightweight and thermal insulating material were successfully prepared by impregnatingAl_(2)O_(3)–SiO_(2)sol into a needle fabric made by coated hollow quartz filament fiber.The coated quartz fiber,aerogels and composites were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),nitrogen adsorption-desorption(BET),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and tensile tests.The effects of different fiber and calcination temperatures on the microstructures and properties ofAl_(2)O_(3)–SiO_(2)composite aerogels were investigated.The test results indicate that the mechanical properties of the aerogels are improved by introducing quartz filament fabrics and the introduction of alumina coating improves the thermal stability of the material.Compared to other fibers,Al_(2)O_(3)-coated hollow quartz fiber has significant advantages as reinforcement for composite,and their tensile strength is well retained after high temperature heat treatment.
