A kind of ruthenium oxide with smaller particles and higher porosity was prepared by a sol-gel process with RuCl3·xH2O and NaHCO3 solution. Several details concerning this new material, including crystal structur...A kind of ruthenium oxide with smaller particles and higher porosity was prepared by a sol-gel process with RuCl3·xH2O and NaHCO3 solution. Several details concerning this new material, including crystal structure, particle size as functions of the temperature, and electrochemical properties were also reported. The optimal annealing temperature was 210 ℃ and the powder annealed at this temperature had a rate capacitance of 541 F/g. In addition, the rate capacitance of the composite electrode reached 802 F/g after 10% carbon black was added, much higher than any previously reported value. High energy density supercapacitors were built with the newly discovered electrode material. Energy densities as high as 67 J/g were obtained based on the RuO2·xH2O alone. By introducing the highly porous carbon black into the electrode, energy densities great than 100 J/g could be achieved. The power density of the capacitor was enhanced significantly.展开更多
To establish a immobilization method of oxygen sensitive dye, a dissolved oxygen sensor based on a sol-gel matrix doped with ruthenium complex ([Ru(bpy)3]2+) as the oxygen-sensitive material is reported. The results i...To establish a immobilization method of oxygen sensitive dye, a dissolved oxygen sensor based on a sol-gel matrix doped with ruthenium complex ([Ru(bpy)3]2+) as the oxygen-sensitive material is reported. The results indicate that the I0 /I100 value of the [Ru(bpy)3]2+-doped in tetraethylorthosilane (TEOS) composite films are estimated to be 10.6, where I0 and I100 correspond to the detected fluorescence intensities in pure nitrogen saturated water and pure oxygen saturated water, respectively. Also, the Stern-Volmer plot shows a very good linearity at low dissolved oxygen concentrations. The response time of the composite films is 5 s upon switching from nitrogen saturated water to oxygen saturated water and 10 s from oxygen saturated water to nitrogen saturated water. The dissolved oxygen sensors based on the ruthenium complex/TEOS composite films exhibit greater sensitivity, stability and faster response time as compared to the existing ones. Furthermore, the thin films possess greatly minimized dye leaching effect.展开更多
Tungsten (VI) oxide (WO3) nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction (XRD), scanning electron micr...Tungsten (VI) oxide (WO3) nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) equipped with energy dispersive X-ray spectroscopy (EDX) were used to characterize the structure and morphology of the materials. There were significant differences between the WO3 materials that were calcinated and those that were subjected to a hydrothermal process. The XRD results revealed that calcination temperatures of 300℃and 400℃ gave hexagonal structures and temperatures of 500℃ and 600℃ gave monoclinic structures. The SEM images showed that an increase in calcination temperature led to a decrease in the WO3 powder particle size. The TEM analysis showed that several nanoparticles agglomerated to form bigger clusters. The hydrothermal process produced hexagonal structures for holding times of 12, 16, and 20 h and monoclinic structures for a holding time of 24 h. The SEM results showed transparent rectangular panicles which according to the TEM results originated from the aggregation of several nanotubes.展开更多
Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. T...Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. The sensor chip was prepared by a spin-coating technique which deposited a thin film of WO3 on an alumina substrate. The chip samples were then calcined at 300, 400, 500 or 600 ℃ for 1 h. The sensitivities of the different sensor chips for CO gas were determined by comparing the changes in electrical resistance in the absence and presence of 50 ppm of CO gas at 200 ℃. The WO3 calcined at 500 ℃ had the highest sensitivity. The sensitivity of this sensor was also measured at CO concentrations of 100 ppm and 200 ppm and at operating temperatures of 30 and 100℃. Thermogravimetric analysis of the WO3 calcined at 500 ℃ indicated that this sample had the highest gas adsorption capacity. This preliminary research has shown that WO3 can serve as a CO gas sensor and that is should be further explored and developed.展开更多
The aim of this study was to develop a method to prepare WO<sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span>&l...The aim of this study was to develop a method to prepare WO<sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film which has high anticorrosion property when it was coated on type 304 stainless steel. A series of WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-modified TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sols were synthesized by peroxo-sol gel method using TiCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> and Na</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">WO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> as the starting materials. TiCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> was converted to Ti(OH)</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> gel. H</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and Na</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">WO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> were added in Ti(OH)</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> solution and heated at 95<span style="white-space:normal;">°</span>C. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sol was transparent, in neutral (pH^7) solution, stable suspension without surfactant, nano-crystallite and no annealing is needed after coating, and very stable for 2 years in stock. WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sol was formed with anatase crystalline structure. These sols were characterized by XRD, TEM, and XPS. The sol was used to coat on stainless steel 304 by dip-coating. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> was anatase in structure as characterized by X-ray diffraction. There were no WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> XRD peaks in the WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sols, indicating that WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> particles were very small, possibly incorporating into TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> structure, providing the amount of WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> was very small. The TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> particles were rhombus shape. WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> had smaller size area than pure TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">. The SEM results showed that the film coated on the glass substrate was very uniform. All films were nonporous and dense films. Its hardness reached 2 H after drying at 100<span style="white-space:normal;">°</span>C, and reached 5 H after annealing at 400<span style="white-space:normal;">°</span>C. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film coated on 304 stainless steel had better anticorrosion capability than the unmodified TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film under UV light illumination. The optimum weight ratio of TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">: WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> was 100:4.</span>展开更多
Electrochemical capacitor (EC) is a promising energy storage device which can be hybridized with other energy conversion or energy storage devices. One type of ECs is pseudocapacitor made of metal oxides. WO3 is an ...Electrochemical capacitor (EC) is a promising energy storage device which can be hybridized with other energy conversion or energy storage devices. One type of ECs is pseudocapacitor made of metal oxides. WO3 is an inexpensive semiconductor metal oxide which has many applications. However the application of WO3 as an EC material was rarely reported. Therefore in this research EC was prepared from WO3 nanomaterial synthesized by a sol-gel process. The WO3 gel was spin-coated on graphite substrates and calcined at various temperatures of 300~C, 400℃, 500℃ and 600℃ for 1 h. Cyclic voltammetry (CV) measurements were used to observe the capacitive property of the WO3 samples. SEM, XRD, FTIR and Brunauer-Emmett-Teller (BET) analyses were used to characterize the material structures. WO3 calcined at 400~C was proved to have the highest capacitance of 233.63 Fo g^-1 (1869 mFo cm-2) at a scan rate of 2 mVo s-1 in 1 mol/L H2SO4 between potentials -0.4 and 0.4 V vs. SCE. Moreover it also showed the most symmetric CV curves as the indication of a good EC. Hence WO3 calcined at 400℃ is a potential candidate for EC material of pseudocapacitor type.展开更多
The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and...The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.展开更多
SiO2 aerogels were produced from tetraethyl orthosilicate (TEOS) as silicon resources,ethanol as solvent and watery HCl or ammonia by sol-gel method and surface modification at ambient pressure.Scanning electronic m...SiO2 aerogels were produced from tetraethyl orthosilicate (TEOS) as silicon resources,ethanol as solvent and watery HCl or ammonia by sol-gel method and surface modification at ambient pressure.Scanning electronic microscopy,Fourier transform infrared spectrometer (FT-IR),pore size distribution measurement,packing density and some other experiment methods were used to characterize the morphology and pore structure and other properties of the silica aerogels.The results show that the silica aerogels have a typical nano-porous microstructure with hydrophobic property.It was discovered that SiO2 aerogels have better properties when the preparation condition is as following the watery HCl concentration is 1%,the aging reagent is CH3CHOHC4H9,the aging time is 20 d,the volume concentration of trimethylchlorosilane (TMCS) in hexane is 6% and the surface modification time is 24 h.展开更多
1 Results Stoichimetric quantities of lithium acetate,nickel acetate and ammonium dihydrogen phosphate were mixed with ethanol and stirred with heating until complete dissolution.A solution of 1 g chitosan in 1% aceti...1 Results Stoichimetric quantities of lithium acetate,nickel acetate and ammonium dihydrogen phosphate were mixed with ethanol and stirred with heating until complete dissolution.A solution of 1 g chitosan in 1% acetic acid was then poured into the heated and stirred solution until all solvents have evaporated.The precursor was then sintered at 500,600,700,800,900 and 1 000 ℃ for 3 hours.X-ray diffraction results showed that single phase LiNiPO4 was obtained at sintering temperatures above 600 ℃.TEM res...展开更多
A sol-gel processing was used to low temperature. Orthorhombic synthesize (Cao.61,Ndo.26)TiO3 (CNT) perovskite structure phase with a smal nanoparticles doped with Li-Cu-B at amount of Li3BO3 secondary phase was f...A sol-gel processing was used to low temperature. Orthorhombic synthesize (Cao.61,Ndo.26)TiO3 (CNT) perovskite structure phase with a smal nanoparticles doped with Li-Cu-B at amount of Li3BO3 secondary phase was formed by calcining the xerogels at 300℃, and monodisperse CNT nano-powders with the grain size of 10-15 nm could be obtained. By using these nanocrystalline CNT powders, dense CNT ceramics could be achieved at the low sintering temperature of 1100℃ due to the effect of the small size nanoparticles and liquid phase Li3BO3. And the dielectric properties with dielectric constant (εr= 89.52), quality value factors with frequency (Q×f=17148 GHz) and the temperature coefficient of resonant frequency (τf) value of +239×10^-6/℃ were achieved.展开更多
Er3+ and Li+ codoped Y3Al5O12(YAG) powders were prepared for a systematic investigation of their upconversion emissions.X-ray diffraction(XRD),upconversion emission spectra,pump power dependence,FT-IR spectra an...Er3+ and Li+ codoped Y3Al5O12(YAG) powders were prepared for a systematic investigation of their upconversion emissions.X-ray diffraction(XRD),upconversion emission spectra,pump power dependence,FT-IR spectra and decay time were studied to characterize the samples.With Li+ doping,the upconversion emission intensity of Er3+ doped YAG powders was obviously enhanced,accompanied with an increase in the ratio of green to red intensity.The enhancement of emission intensity could be attributed to two mechanisms:one was the distortion of local crystal field around Er3+,and the other was the decrease in the amount of CO32-and OH-groups.Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er3+/Li+ powders.展开更多
文摘A kind of ruthenium oxide with smaller particles and higher porosity was prepared by a sol-gel process with RuCl3·xH2O and NaHCO3 solution. Several details concerning this new material, including crystal structure, particle size as functions of the temperature, and electrochemical properties were also reported. The optimal annealing temperature was 210 ℃ and the powder annealed at this temperature had a rate capacitance of 541 F/g. In addition, the rate capacitance of the composite electrode reached 802 F/g after 10% carbon black was added, much higher than any previously reported value. High energy density supercapacitors were built with the newly discovered electrode material. Energy densities as high as 67 J/g were obtained based on the RuO2·xH2O alone. By introducing the highly porous carbon black into the electrode, energy densities great than 100 J/g could be achieved. The power density of the capacitor was enhanced significantly.
基金Funded by the Open Project of State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials of Sichuan Province (No.10zxfk23)Scientific Research Project of Sichuan Normal University (No.11KYL06)
文摘To establish a immobilization method of oxygen sensitive dye, a dissolved oxygen sensor based on a sol-gel matrix doped with ruthenium complex ([Ru(bpy)3]2+) as the oxygen-sensitive material is reported. The results indicate that the I0 /I100 value of the [Ru(bpy)3]2+-doped in tetraethylorthosilane (TEOS) composite films are estimated to be 10.6, where I0 and I100 correspond to the detected fluorescence intensities in pure nitrogen saturated water and pure oxygen saturated water, respectively. Also, the Stern-Volmer plot shows a very good linearity at low dissolved oxygen concentrations. The response time of the composite films is 5 s upon switching from nitrogen saturated water to oxygen saturated water and 10 s from oxygen saturated water to nitrogen saturated water. The dissolved oxygen sensors based on the ruthenium complex/TEOS composite films exhibit greater sensitivity, stability and faster response time as compared to the existing ones. Furthermore, the thin films possess greatly minimized dye leaching effect.
文摘Tungsten (VI) oxide (WO3) nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) equipped with energy dispersive X-ray spectroscopy (EDX) were used to characterize the structure and morphology of the materials. There were significant differences between the WO3 materials that were calcinated and those that were subjected to a hydrothermal process. The XRD results revealed that calcination temperatures of 300℃and 400℃ gave hexagonal structures and temperatures of 500℃ and 600℃ gave monoclinic structures. The SEM images showed that an increase in calcination temperature led to a decrease in the WO3 powder particle size. The TEM analysis showed that several nanoparticles agglomerated to form bigger clusters. The hydrothermal process produced hexagonal structures for holding times of 12, 16, and 20 h and monoclinic structures for a holding time of 24 h. The SEM results showed transparent rectangular panicles which according to the TEM results originated from the aggregation of several nanotubes.
文摘Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. The sensor chip was prepared by a spin-coating technique which deposited a thin film of WO3 on an alumina substrate. The chip samples were then calcined at 300, 400, 500 or 600 ℃ for 1 h. The sensitivities of the different sensor chips for CO gas were determined by comparing the changes in electrical resistance in the absence and presence of 50 ppm of CO gas at 200 ℃. The WO3 calcined at 500 ℃ had the highest sensitivity. The sensitivity of this sensor was also measured at CO concentrations of 100 ppm and 200 ppm and at operating temperatures of 30 and 100℃. Thermogravimetric analysis of the WO3 calcined at 500 ℃ indicated that this sample had the highest gas adsorption capacity. This preliminary research has shown that WO3 can serve as a CO gas sensor and that is should be further explored and developed.
文摘The aim of this study was to develop a method to prepare WO<sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film which has high anticorrosion property when it was coated on type 304 stainless steel. A series of WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-modified TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sols were synthesized by peroxo-sol gel method using TiCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> and Na</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">WO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> as the starting materials. TiCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> was converted to Ti(OH)</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> gel. H</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and Na</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">WO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> were added in Ti(OH)</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> solution and heated at 95<span style="white-space:normal;">°</span>C. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sol was transparent, in neutral (pH^7) solution, stable suspension without surfactant, nano-crystallite and no annealing is needed after coating, and very stable for 2 years in stock. WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sol was formed with anatase crystalline structure. These sols were characterized by XRD, TEM, and XPS. The sol was used to coat on stainless steel 304 by dip-coating. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> was anatase in structure as characterized by X-ray diffraction. There were no WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> XRD peaks in the WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sols, indicating that WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> particles were very small, possibly incorporating into TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> structure, providing the amount of WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> was very small. The TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> particles were rhombus shape. WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> had smaller size area than pure TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">. The SEM results showed that the film coated on the glass substrate was very uniform. All films were nonporous and dense films. Its hardness reached 2 H after drying at 100<span style="white-space:normal;">°</span>C, and reached 5 H after annealing at 400<span style="white-space:normal;">°</span>C. The WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">-TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film coated on 304 stainless steel had better anticorrosion capability than the unmodified TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> film under UV light illumination. The optimum weight ratio of TiO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">: WO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> was 100:4.</span>
基金The financial support from Indonesia Toray Science Foundation (ITSF) through Science and Technology Research Grant (STRG) 2012 is gratefully acknowledged.
文摘Electrochemical capacitor (EC) is a promising energy storage device which can be hybridized with other energy conversion or energy storage devices. One type of ECs is pseudocapacitor made of metal oxides. WO3 is an inexpensive semiconductor metal oxide which has many applications. However the application of WO3 as an EC material was rarely reported. Therefore in this research EC was prepared from WO3 nanomaterial synthesized by a sol-gel process. The WO3 gel was spin-coated on graphite substrates and calcined at various temperatures of 300~C, 400℃, 500℃ and 600℃ for 1 h. Cyclic voltammetry (CV) measurements were used to observe the capacitive property of the WO3 samples. SEM, XRD, FTIR and Brunauer-Emmett-Teller (BET) analyses were used to characterize the material structures. WO3 calcined at 400~C was proved to have the highest capacitance of 233.63 Fo g^-1 (1869 mFo cm-2) at a scan rate of 2 mVo s-1 in 1 mol/L H2SO4 between potentials -0.4 and 0.4 V vs. SCE. Moreover it also showed the most symmetric CV curves as the indication of a good EC. Hence WO3 calcined at 400℃ is a potential candidate for EC material of pseudocapacitor type.
文摘The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.
基金Sponsored by the National Research Fund for Fundamental Key Projects (2002CB211800)Project of Beijing Key Laboratory of Environmental Science and Engineering (SYS100070416)
文摘SiO2 aerogels were produced from tetraethyl orthosilicate (TEOS) as silicon resources,ethanol as solvent and watery HCl or ammonia by sol-gel method and surface modification at ambient pressure.Scanning electronic microscopy,Fourier transform infrared spectrometer (FT-IR),pore size distribution measurement,packing density and some other experiment methods were used to characterize the morphology and pore structure and other properties of the silica aerogels.The results show that the silica aerogels have a typical nano-porous microstructure with hydrophobic property.It was discovered that SiO2 aerogels have better properties when the preparation condition is as following the watery HCl concentration is 1%,the aging reagent is CH3CHOHC4H9,the aging time is 20 d,the volume concentration of trimethylchlorosilane (TMCS) in hexane is 6% and the surface modification time is 24 h.
文摘1 Results Stoichimetric quantities of lithium acetate,nickel acetate and ammonium dihydrogen phosphate were mixed with ethanol and stirred with heating until complete dissolution.A solution of 1 g chitosan in 1% acetic acid was then poured into the heated and stirred solution until all solvents have evaporated.The precursor was then sintered at 500,600,700,800,900 and 1 000 ℃ for 3 hours.X-ray diffraction results showed that single phase LiNiPO4 was obtained at sintering temperatures above 600 ℃.TEM res...
基金supported by the National Key Technology Support Program (No. 2009BAG12A07)
文摘A sol-gel processing was used to low temperature. Orthorhombic synthesize (Cao.61,Ndo.26)TiO3 (CNT) perovskite structure phase with a smal nanoparticles doped with Li-Cu-B at amount of Li3BO3 secondary phase was formed by calcining the xerogels at 300℃, and monodisperse CNT nano-powders with the grain size of 10-15 nm could be obtained. By using these nanocrystalline CNT powders, dense CNT ceramics could be achieved at the low sintering temperature of 1100℃ due to the effect of the small size nanoparticles and liquid phase Li3BO3. And the dielectric properties with dielectric constant (εr= 89.52), quality value factors with frequency (Q×f=17148 GHz) and the temperature coefficient of resonant frequency (τf) value of +239×10^-6/℃ were achieved.
基金Project supported by the National Natural Science Foundation of China (50672019 and 10804024)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministrythe Fundamental Research Funds for the Central Universities (HIT.NSRIF.2009056)
文摘Er3+ and Li+ codoped Y3Al5O12(YAG) powders were prepared for a systematic investigation of their upconversion emissions.X-ray diffraction(XRD),upconversion emission spectra,pump power dependence,FT-IR spectra and decay time were studied to characterize the samples.With Li+ doping,the upconversion emission intensity of Er3+ doped YAG powders was obviously enhanced,accompanied with an increase in the ratio of green to red intensity.The enhancement of emission intensity could be attributed to two mechanisms:one was the distortion of local crystal field around Er3+,and the other was the decrease in the amount of CO32-and OH-groups.Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er3+/Li+ powders.