Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method...Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method, and composite films of gold nanoparticle dispersed in silica matrix were formed by heat-treating the polyelectrolyte/gold nanoparticle/silica nanoparticle composite films to eliminate the polyelectrolyte. The obtained composite films were investigated with UV-vis, TEM, AFM and XRD. The results show that the self-assembly multilayer method is a promising process to produce composite films of gold nanoparticle-dispersed in organic and/or inorganic matrixes.展开更多
LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such...LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis(TG/DTA),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM) and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy(EIS) and differential capacity curves(dQ/dE).Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth(50nm) with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of(100 nm) while low level of Al-doping spinel(LiNio.5Alo.05Mn1.45O4) displaying cloudy particles with agglomerated particles of(50nm).The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle(capacity retention of 92%) over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.展开更多
Here, large-scale and uniform hexagonal zinc oxide(ZnO) nanosheet films were deposited onto indium tin oxide(ITO)-coated transparent conducting glass substrates via a facile galvanic displacement deposition process. C...Here, large-scale and uniform hexagonal zinc oxide(ZnO) nanosheet films were deposited onto indium tin oxide(ITO)-coated transparent conducting glass substrates via a facile galvanic displacement deposition process. Compared with other commonly used solution methods, this process avoids high temperature and electric power as well as supporting agents to make it simple and cost-effective. The as-fabricated ZnO nanosheet films have uniform hexagonal wurtzite structure. The photoelectrochemical(PEC) cell based on ZnO nanosheet film/ITO photoelectrode was also fabricated and its performance was improved by optimizing the solution concentration. A higher photocurrent density of*500 l A cm^(-2)under AM 1.5 G simulated illumination of 100 m W cm^(-2)with zero bias potential(vs. Ag/AgCl electrode) was obtained, which may ascribe to the increased surface-to-volume ratio of disordered Zn O nanosheet arrays. Our developed method may be used to deposit other oxide semiconductors, and the Zn O nanosheet film/ITO PEC cell can be used to design low-cost optoelectronic and photoelectrochemical devices.展开更多
CeO2 ultrafine powder was prepared by sol-gel method.XRD showed that samples were amorphous when calcination temperature was below 230℃,and single phase CeO2 ultrafine powders could be obtained above 250℃.It was fou...CeO2 ultrafine powder was prepared by sol-gel method.XRD showed that samples were amorphous when calcination temperature was below 230℃,and single phase CeO2 ultrafine powders could be obtained above 250℃.It was found that Ce(3+) and Ce(4+)coexisted in the dried gel,the content of Ce(3+)lowered gradually and that of Ce(4+)increased in samples when calcining temperature increased.Ce(3+)was converted to Ce(4+)completel at 250℃.展开更多
Tungsten nanoparticle-strengthened Cu composites were prepared from nanopowder synthesized by a sol–gel method and in-situ hydrogen reduction.The tungsten particles in the Cu matrix were well-dispersed with an averag...Tungsten nanoparticle-strengthened Cu composites were prepared from nanopowder synthesized by a sol–gel method and in-situ hydrogen reduction.The tungsten particles in the Cu matrix were well-dispersed with an average size of approximately 100–200 nm.The addition of nanosized W particles remarkably improves the mechanical properties,while the electrical conductivity did not substantially decrease.The Cu–W composite with 6 wt%W has the most comprehensive properties with an ultimate strength of 310 MPa,yield strength of 238 MPa,hardness of HV 108 and electrical conductivity of 90%IACS.The enhanced mechanical property and only a small loss of electrical conductivity demonstrate the potential of this new strategy to prepare W nanoparticle-strengthened Cu composites.展开更多
The rare earth complex Eu(TTA) 3 was successfully encapsulated into MCM 41 mesoporous molecular sieve by the addition of the complex into the sol gel mixture for the synthesis of MCM 41 mesoporous material under m...The rare earth complex Eu(TTA) 3 was successfully encapsulated into MCM 41 mesoporous molecular sieve by the addition of the complex into the sol gel mixture for the synthesis of MCM 41 mesoporous material under microwave radiation. The as synthesized MCM 41 hosted Eu(TTA) 3 mesophase was confirmed to possess hexagonally ordered mesostructure and a uniform crystal size of about 30 nm with XRD and HRTEM techniques. Moreover, the IR spectrum, photoluminescence effect and fluorescence lifetime of the Eu(TTA) 3/MCM 41 hybrid were also studied. An increase in Stokes' shift and no change in luminescence lifetime were observed to the resultant mesophase in comparison with Eu(TTA) 3 in ethanol solution.展开更多
The precursor of ultrafine In 2O 3 powder was prepared by the hydrolysis, peptization and gelation of InCl 3·4H 2O used as raw material. After calcination, ultrafine In 2O 3 powder was obtained. The particl...The precursor of ultrafine In 2O 3 powder was prepared by the hydrolysis, peptization and gelation of InCl 3·4H 2O used as raw material. After calcination, ultrafine In 2O 3 powder was obtained. The particles were characterized by the methods of thermo gravimetric and differential thermal analysis (TG DTA), X ray diffractometry (XRD) and transmission electron microscopy (TEM), respectively.展开更多
Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase ...Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcina- tion temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B(RhB) solution and gaseous formaldehyde(FAD). With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550℃ for I0 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gase-ous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic per- formance of the prepared ZnWO4.展开更多
Nanocrystal SmBO3 powders were synthesized by nitrate-citrate sol-gel combustion method. The phase evolution, morphologies and absorbency of the synthesized powders were characterized by X-ray diffraction (XRD), Fie...Nanocrystal SmBO3 powders were synthesized by nitrate-citrate sol-gel combustion method. The phase evolution, morphologies and absorbency of the synthesized powders were characterized by X-ray diffraction (XRD), Field emission scanning electronic microscope (FESEM), Fourier transform infrared spectroscopy (FFIR) and UV-3101PC spectrophotometer (UVPC), respectively. XRD and FESEM results showed that pure SmBO3 phase was obtained at 750 ℃, with an average original particle size of about 100 nm. FTIR showed that there were apparently concentrated absorbent peaks between 500 and 1400 cm^-1. Moreover, the reflectivity of the powders apparently decreased at the wavelength between 1.05 and 1.15 μm. Therefore, SmBO3 might be a kind of absorbent material for infrared laser.展开更多
Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were...Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were characterized by scanning electron microscopy (SEM) , X-ray diffraction (XRD), transmission electron microscopy ( TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer ( UV-VIS). The photocatalytic activity of TiO2 thin films was evaluated for the photocatalytic decolorization of aqueous methyl orange . The effects of film thickness on the crystalline phase, grain size, transmittance and photocatalytic activity of nanometer Ti02 thin films were discussed.展开更多
A series of red-emitting Ca2_xA12SiOT:xEu^3+ (x = 1 mol.%-10 tool.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and lum...A series of red-emitting Ca2_xA12SiOT:xEu^3+ (x = 1 mol.%-10 tool.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and luminescence properties of Ca2A12SiO7:Eu^3+ phosphors were investigated. X-ray diffraction (XRD) profiles showed that all peaks could be attributed to the tetragonal Ca2A12SiO7 phase when the sample was annealed at 1000℃. Scanning electron microscopy (SEM) micrographs indicate that the phosphors have an irregularly rounded mor- phology with particles of about 200 nm. Excitation spectra showed that the strong broad band at around 258 nm and weak sharp lines in 350-490 nm were attributed to the charge transfer band of Eu^3+-O^2- and f-f transitions within the 4f^6 configuration of Eu^3+ ions, respectively. Emission spectra implied that the red luminescence could be attributed to the transitions from the ^5D0 excited level to the 7Fj (J = 0, 1, 2, 3, 4) levels of Eu3+ions with the main electric dipole transition ^5D0→^7F2 (618 and 620 nm), and Eu^3+ ions prefer to occupy a lower symmetry site in the crystal lattice. Moreover, the photoluminescence (PL) intensity was strongly dependent on both the sintering temperature and doping concentration, and the highest PL intensity was observed at an Eu^3+ concentration x = 7 mol.% after annealing at ll00℃. The obtained Ca2A12SiO7:Eu^+3+ phosphor may have potential application for the red lamp phosphor.展开更多
Undoped and Na-doped ZnO films were deposited by sol-gel method.The effects of sodium incorporation on structure,surface morphology and optical constants of the films were investigated.X-ray diffraction patterns show ...Undoped and Na-doped ZnO films were deposited by sol-gel method.The effects of sodium incorporation on structure,surface morphology and optical constants of the films were investigated.X-ray diffraction patterns show the hexagonal wurtzite polycrystalline structure and that the sodium incorporation leads to the change in the structural characteristics of ZnO films.The SEM observations show that the surface morphology of the films is affected by the sodium incorporation.The transmission spectra show that the average transmittance of the films is above 85% in the visible range.The absorption edge initially blue-shifts and then red-shifts with the increase of Na doping content.The optical constants of these films were calculated using transmission spectra.Refractive indices of the films in the visible range decrease at first and then increase with increasing Na doping content.展开更多
Nanometer Al_2O_3 is one of new types of functional materials with broad application and development prospects in the future. The basic principle and ways of nanometer Al_2O_3 fabricated using sol-gel technique were i...Nanometer Al_2O_3 is one of new types of functional materials with broad application and development prospects in the future. The basic principle and ways of nanometer Al_2O_3 fabricated using sol-gel technique were introduced, and the factors affecting nanometer Al_2O_3 fabricated using sol-gel method were analyzed. The progress in research on nanometer Al_2O_3 and the application fields of nanometer Al_2O_3 were reviewed. The existing problems and the problems prospect for nanometer Al_2O_3 were pointed out.展开更多
Ink-jet printing of ceramic thick films is one of low cost on-site ceramic pattern fabrication methods.It is necessary to investigate the rheological behaviour of ceramic inks and drying behaviour of droplets.Two kind...Ink-jet printing of ceramic thick films is one of low cost on-site ceramic pattern fabrication methods.It is necessary to investigate the rheological behaviour of ceramic inks and drying behaviour of droplets.Two kinds of BaTiO3 ceramic inks were prepared by mechanical mixing and sol-gel methods,respectively.The effect of preparation parameters,such as quantity of polyacrylic acid(PAA)and solid content,on physicochemical and rheologic properties of the ceramic inks was investigated.The results show that they satisfy the requirements of continuous ink-jet printing.The appearances of printed dots and single printed layers were observed by SEM.The SEM images indicate that dots printed with mixing method ink are in ring shape,and dots printed with sol-gel method ink are in pancake shape,so the printed layer surface with the latter ink is smoother.The causes of these phenomena were discussed.展开更多
The CaCu3Ti4O12 xerogels,powders and ceramics were prepared through the sol-gel method using two kinds of organic acid(decanoic acid and decanedioic acid).The xerogels,powders and ceramics were characterized by the me...The CaCu3Ti4O12 xerogels,powders and ceramics were prepared through the sol-gel method using two kinds of organic acid(decanoic acid and decanedioic acid).The xerogels,powders and ceramics were characterized by the methods of TG-DTG,FT-IR,XRD,SEM and TEM.The dielectric properties of the ceramics were also measured.The results indicated that the powders calcined at 850°C for 2h are both nanometer scale particles.After sintering,the ceramics mainly consist of the CaCu3Ti4O12 phase.Compared with the powders prepared using monoacid,the particle size of the powders prepared using diacid obviously increases,and the grain size,the relative density and the whole permittivity of the ceramics increase as well.Specially,the ceramic prepared using decanedioic acid has higher relative density(97.3%),dielectric constant(316 808)and lower dielectric loss(0.242 5)at 30°C(10kHz)展开更多
The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction per...The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction performances of catalysts were investigated with BET, TPR, and TPD. Compared with the catalyst prepared by the impregnation method, the results indicated that the catalysts prepared by the sol-gel method had larger specific surface area, showing higher catalytic activities and exhibiting perfect desorption and reduction performances. In addition, the modification effects of adding La were studied, and it was found that the 0.75NLBT catalyst constituted of 5wt.%Ni-0.75wt.%La was optimal.展开更多
Highly ordered nanowire/tube arrays of Ni0.5Zn0.5Fe2O4were fabricated by the sol-gel method in the pores of anodic alumina membrane (AAM). Whether nanowires or nanotubes were fabricated depends on immersion time. Th...Highly ordered nanowire/tube arrays of Ni0.5Zn0.5Fe2O4were fabricated by the sol-gel method in the pores of anodic alumina membrane (AAM). Whether nanowires or nanotubes were fabricated depends on immersion time. The immersion time was 15- 40 s for nanotubes and over 60 s for nanowires. The topography and crystalline structure of the nanowire arrays were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). It was found that the length and diameter of the Ni0.5Zn0.5Fe2O4 nanowires are related to the thickness of the AAM and the diameter of the pores. The results indicated that the Ni0.5Zn0.5Fe2O4 nanowires are uniform and parallel to each other.展开更多
Eu 2+, Dy 3+ co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200 ℃ for 2 h. The samples were characterized by X-ray diffract...Eu 2+, Dy 3+ co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200 ℃ for 2 h. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD show that the single crystalline phase is α-SrAl_2O_4. According to the observation of SEM, the particles of the samples are needle-like. Compared with the samples synthesized by solid state reaction, the grain size of the sol-gel method is to nanometer grade. A clear blue shift occurs in the excitation and emission spectra. The blue shift in nanocrystalline SrAl_2O_4∶Eu, Dy phosphor can be attributed to the quantum-size-effect of the luminescent particles.展开更多
基金This work was supported by the Natural Science Foundation of Hubei Province(Project No.2000J002)
文摘Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method, and composite films of gold nanoparticle dispersed in silica matrix were formed by heat-treating the polyelectrolyte/gold nanoparticle/silica nanoparticle composite films to eliminate the polyelectrolyte. The obtained composite films were investigated with UV-vis, TEM, AFM and XRD. The results show that the self-assembly multilayer method is a promising process to produce composite films of gold nanoparticle-dispersed in organic and/or inorganic matrixes.
基金support given under the "Brain Pool Program of the Korean Federation of Science and Technology Societies" (KOFST), Republic of South Koreasupported by the Human Resources Development Program (No. 20124010203270) of the Korea Institute of Energy Technology EvaluationPlanning (KETEP) grant funded by the Korea Government Ministry of Trade, Industry and Energy
文摘LiMnOand LiNiAlyMnO(x= 0.50;y = 0.05-0.50) powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis(TG/DTA),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM) and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy(EIS) and differential capacity curves(dQ/dE).Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth(50nm) with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of(100 nm) while low level of Al-doping spinel(LiNio.5Alo.05Mn1.45O4) displaying cloudy particles with agglomerated particles of(50nm).The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle(capacity retention of 92%) over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.
基金supported by the National Major Basic Research Project of 2012CB934302the National 863 Program2011AA050518+1 种基金the Natural Science Foundation of China(Grant No.1117419711574203 and 61234005)
文摘Here, large-scale and uniform hexagonal zinc oxide(ZnO) nanosheet films were deposited onto indium tin oxide(ITO)-coated transparent conducting glass substrates via a facile galvanic displacement deposition process. Compared with other commonly used solution methods, this process avoids high temperature and electric power as well as supporting agents to make it simple and cost-effective. The as-fabricated ZnO nanosheet films have uniform hexagonal wurtzite structure. The photoelectrochemical(PEC) cell based on ZnO nanosheet film/ITO photoelectrode was also fabricated and its performance was improved by optimizing the solution concentration. A higher photocurrent density of*500 l A cm^(-2)under AM 1.5 G simulated illumination of 100 m W cm^(-2)with zero bias potential(vs. Ag/AgCl electrode) was obtained, which may ascribe to the increased surface-to-volume ratio of disordered Zn O nanosheet arrays. Our developed method may be used to deposit other oxide semiconductors, and the Zn O nanosheet film/ITO PEC cell can be used to design low-cost optoelectronic and photoelectrochemical devices.
文摘CeO2 ultrafine powder was prepared by sol-gel method.XRD showed that samples were amorphous when calcination temperature was below 230℃,and single phase CeO2 ultrafine powders could be obtained above 250℃.It was found that Ce(3+) and Ce(4+)coexisted in the dried gel,the content of Ce(3+)lowered gradually and that of Ce(4+)increased in samples when calcining temperature increased.Ce(3+)was converted to Ce(4+)completel at 250℃.
基金supported by the Fundamental Research Funds for the Central Universities (No. FRF-TP-18-029A2)State Key Lab of Advanced Metals and Materials of China (No. 2019-Z10)
文摘Tungsten nanoparticle-strengthened Cu composites were prepared from nanopowder synthesized by a sol–gel method and in-situ hydrogen reduction.The tungsten particles in the Cu matrix were well-dispersed with an average size of approximately 100–200 nm.The addition of nanosized W particles remarkably improves the mechanical properties,while the electrical conductivity did not substantially decrease.The Cu–W composite with 6 wt%W has the most comprehensive properties with an ultimate strength of 310 MPa,yield strength of 238 MPa,hardness of HV 108 and electrical conductivity of 90%IACS.The enhanced mechanical property and only a small loss of electrical conductivity demonstrate the potential of this new strategy to prepare W nanoparticle-strengthened Cu composites.
文摘The rare earth complex Eu(TTA) 3 was successfully encapsulated into MCM 41 mesoporous molecular sieve by the addition of the complex into the sol gel mixture for the synthesis of MCM 41 mesoporous material under microwave radiation. The as synthesized MCM 41 hosted Eu(TTA) 3 mesophase was confirmed to possess hexagonally ordered mesostructure and a uniform crystal size of about 30 nm with XRD and HRTEM techniques. Moreover, the IR spectrum, photoluminescence effect and fluorescence lifetime of the Eu(TTA) 3/MCM 41 hybrid were also studied. An increase in Stokes' shift and no change in luminescence lifetime were observed to the resultant mesophase in comparison with Eu(TTA) 3 in ethanol solution.
文摘The precursor of ultrafine In 2O 3 powder was prepared by the hydrolysis, peptization and gelation of InCl 3·4H 2O used as raw material. After calcination, ultrafine In 2O 3 powder was obtained. The particles were characterized by the methods of thermo gravimetric and differential thermal analysis (TG DTA), X ray diffractometry (XRD) and transmission electron microscopy (TEM), respectively.
基金Supported by the National Natural Science Foundation of China(Nos.20433010and20571047)Specialized Research Fundfor the Doctoral Program of Higher Education(No.20060003082).
文摘Nanosized ZnWO4 photocatalysts were successfully synthesized via the sol-gel process in a temperature range of 450-800℃. The grain size, crystal size, and crystallinity of ZnWO4 particles increased with the increase of calcina- tion temperature and prolonging calcination time. The photocatalytic activity was measured for the degradation of an aqueous Rhodamine-B(RhB) solution and gaseous formaldehyde(FAD). With the increase of calcination temperature and time, the activities increased to a maximum and then decreased. ZnWO4 photocatalyst prepared at 550℃ for I0 h showed the highest activity, which is similar to the photocatalytic activity of P25TiO2 for the degradation of gase-ous FAD. High crystallinity, large surface area, and good dispersion are responsible for the high photocatalytic per- formance of the prepared ZnWO4.
基金supported by the 973 Research Project of China (6134502)
文摘Nanocrystal SmBO3 powders were synthesized by nitrate-citrate sol-gel combustion method. The phase evolution, morphologies and absorbency of the synthesized powders were characterized by X-ray diffraction (XRD), Field emission scanning electronic microscope (FESEM), Fourier transform infrared spectroscopy (FFIR) and UV-3101PC spectrophotometer (UVPC), respectively. XRD and FESEM results showed that pure SmBO3 phase was obtained at 750 ℃, with an average original particle size of about 100 nm. FTIR showed that there were apparently concentrated absorbent peaks between 500 and 1400 cm^-1. Moreover, the reflectivity of the powders apparently decreased at the wavelength between 1.05 and 1.15 μm. Therefore, SmBO3 might be a kind of absorbent material for infrared laser.
基金This work was financially supported by Foundation for Uni-versity Key Teacher by the Ministry of Education, the National Natu-ral Science Foundation of China (No. 50072016) and the Key Re-search Project of the Ministry of Education(No.99087)
文摘Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were characterized by scanning electron microscopy (SEM) , X-ray diffraction (XRD), transmission electron microscopy ( TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer ( UV-VIS). The photocatalytic activity of TiO2 thin films was evaluated for the photocatalytic decolorization of aqueous methyl orange . The effects of film thickness on the crystalline phase, grain size, transmittance and photocatalytic activity of nanometer Ti02 thin films were discussed.
基金supported by the National Natural Science Foundation of China (No. 10874160)the Science and Technology Foundation of Guangdong Province,China (No. 2007173)the Science and Technology Foundation of Jiangmen City, China (No. 2007028)
文摘A series of red-emitting Ca2_xA12SiOT:xEu^3+ (x = 1 mol.%-10 tool.%) phosphors were synthesized by the sol-gel method. The effects of annealing temperature and doping concentration on the crystal structure and luminescence properties of Ca2A12SiO7:Eu^3+ phosphors were investigated. X-ray diffraction (XRD) profiles showed that all peaks could be attributed to the tetragonal Ca2A12SiO7 phase when the sample was annealed at 1000℃. Scanning electron microscopy (SEM) micrographs indicate that the phosphors have an irregularly rounded mor- phology with particles of about 200 nm. Excitation spectra showed that the strong broad band at around 258 nm and weak sharp lines in 350-490 nm were attributed to the charge transfer band of Eu^3+-O^2- and f-f transitions within the 4f^6 configuration of Eu^3+ ions, respectively. Emission spectra implied that the red luminescence could be attributed to the transitions from the ^5D0 excited level to the 7Fj (J = 0, 1, 2, 3, 4) levels of Eu3+ions with the main electric dipole transition ^5D0→^7F2 (618 and 620 nm), and Eu^3+ ions prefer to occupy a lower symmetry site in the crystal lattice. Moreover, the photoluminescence (PL) intensity was strongly dependent on both the sintering temperature and doping concentration, and the highest PL intensity was observed at an Eu^3+ concentration x = 7 mol.% after annealing at ll00℃. The obtained Ca2A12SiO7:Eu^+3+ phosphor may have potential application for the red lamp phosphor.
基金Project(50872001) supported by the National Natural Science Foundation of ChinaProject(20060357003) supported by Research Fund for the Doctoral Program of Higher Education of ChinaProject(KJ2010A284) supported by the Natural Science Foundation of Anhui Higher Education Institution of China
文摘Undoped and Na-doped ZnO films were deposited by sol-gel method.The effects of sodium incorporation on structure,surface morphology and optical constants of the films were investigated.X-ray diffraction patterns show the hexagonal wurtzite polycrystalline structure and that the sodium incorporation leads to the change in the structural characteristics of ZnO films.The SEM observations show that the surface morphology of the films is affected by the sodium incorporation.The transmission spectra show that the average transmittance of the films is above 85% in the visible range.The absorption edge initially blue-shifts and then red-shifts with the increase of Na doping content.The optical constants of these films were calculated using transmission spectra.Refractive indices of the films in the visible range decrease at first and then increase with increasing Na doping content.
文摘Nanometer Al_2O_3 is one of new types of functional materials with broad application and development prospects in the future. The basic principle and ways of nanometer Al_2O_3 fabricated using sol-gel technique were introduced, and the factors affecting nanometer Al_2O_3 fabricated using sol-gel method were analyzed. The progress in research on nanometer Al_2O_3 and the application fields of nanometer Al_2O_3 were reviewed. The existing problems and the problems prospect for nanometer Al_2O_3 were pointed out.
基金Project(106151)supported by the Major Program of the Ministry of Education of ChinaProject(59842001)supported by the National Natural Science Foundation of China
文摘Ink-jet printing of ceramic thick films is one of low cost on-site ceramic pattern fabrication methods.It is necessary to investigate the rheological behaviour of ceramic inks and drying behaviour of droplets.Two kinds of BaTiO3 ceramic inks were prepared by mechanical mixing and sol-gel methods,respectively.The effect of preparation parameters,such as quantity of polyacrylic acid(PAA)and solid content,on physicochemical and rheologic properties of the ceramic inks was investigated.The results show that they satisfy the requirements of continuous ink-jet printing.The appearances of printed dots and single printed layers were observed by SEM.The SEM images indicate that dots printed with mixing method ink are in ring shape,and dots printed with sol-gel method ink are in pancake shape,so the printed layer surface with the latter ink is smoother.The causes of these phenomena were discussed.
基金Projects(CC20120031,CC20110048)supported by Changzhou Science and Technology Innovation Project,China
文摘The CaCu3Ti4O12 xerogels,powders and ceramics were prepared through the sol-gel method using two kinds of organic acid(decanoic acid and decanedioic acid).The xerogels,powders and ceramics were characterized by the methods of TG-DTG,FT-IR,XRD,SEM and TEM.The dielectric properties of the ceramics were also measured.The results indicated that the powders calcined at 850°C for 2h are both nanometer scale particles.After sintering,the ceramics mainly consist of the CaCu3Ti4O12 phase.Compared with the powders prepared using monoacid,the particle size of the powders prepared using diacid obviously increases,and the grain size,the relative density and the whole permittivity of the ceramics increase as well.Specially,the ceramic prepared using decanedioic acid has higher relative density(97.3%),dielectric constant(316 808)and lower dielectric loss(0.242 5)at 30°C(10kHz)
基金supported by the Jiangxi Provincial Department of Education
文摘The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction performances of catalysts were investigated with BET, TPR, and TPD. Compared with the catalyst prepared by the impregnation method, the results indicated that the catalysts prepared by the sol-gel method had larger specific surface area, showing higher catalytic activities and exhibiting perfect desorption and reduction performances. In addition, the modification effects of adding La were studied, and it was found that the 0.75NLBT catalyst constituted of 5wt.%Ni-0.75wt.%La was optimal.
文摘Highly ordered nanowire/tube arrays of Ni0.5Zn0.5Fe2O4were fabricated by the sol-gel method in the pores of anodic alumina membrane (AAM). Whether nanowires or nanotubes were fabricated depends on immersion time. The immersion time was 15- 40 s for nanotubes and over 60 s for nanowires. The topography and crystalline structure of the nanowire arrays were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). It was found that the length and diameter of the Ni0.5Zn0.5Fe2O4 nanowires are related to the thickness of the AAM and the diameter of the pores. The results indicated that the Ni0.5Zn0.5Fe2O4 nanowires are uniform and parallel to each other.
文摘Eu 2+, Dy 3+ co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200 ℃ for 2 h. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD show that the single crystalline phase is α-SrAl_2O_4. According to the observation of SEM, the particles of the samples are needle-like. Compared with the samples synthesized by solid state reaction, the grain size of the sol-gel method is to nanometer grade. A clear blue shift occurs in the excitation and emission spectra. The blue shift in nanocrystalline SrAl_2O_4∶Eu, Dy phosphor can be attributed to the quantum-size-effect of the luminescent particles.