We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of...We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of （Sr, Bi, Si, Ta）-doped TiO2- based varistor ceramics sintered at 1 250℃ for 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, and 5.0 h, respectively. The samples were characterized by X-ray diffraction, breakdown voltage, and complex impedance. The results show that as the soaking time increases from 0.5 h to 5.0 h, the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases. We suggest that, considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics, the optimal soaking time is between 2.0 h and 3.0 h.展开更多
This paper reports the formation and some properties of a new class of chalcohalide glasses in the As2Tef iodide systems. The As2Te3-Pb12, As2Te3-HgI2, As2Te3-CitI and As2Te3-AgI systems can form stable bulk glasses i...This paper reports the formation and some properties of a new class of chalcohalide glasses in the As2Tef iodide systems. The As2Te3-Pb12, As2Te3-HgI2, As2Te3-CitI and As2Te3-AgI systems can form stable bulk glasses in wide composition regions ?and no bulk glass formation was found in the As2Te3-TH sys-tem. As2Te3-based glasses have glass transition tempera-展开更多
Larger amounts of alkalis, alkali earth metals and sulfides in flue gas from glass furnace were easier to deactivate selective catalytic reduction （SCR） catalyst compared to the flue gases from other stationary sour...Larger amounts of alkalis, alkali earth metals and sulfides in flue gas from glass furnace were easier to deactivate selective catalytic reduction （SCR） catalyst compared to the flue gases from other stationary sources. Catalyst regeneration has been an emerging research topic for flue gas denitrification in glass furnace. Regeneration of the deactivated TiO2-ZrO2-CeO2 /Al2TiO 5 -TiO2-SiO2 （ATS） complex phase ceramics catalysts used for NH3 -SCR of NO x in glass furnace was studied in this work. Effects of regeneration methods, including washing with different aqueous solutions and sulfuric acid, thermal regeneration, thermal reduction regeneration, and thermal regeneration with SO2 , on catalytic performance were comparatively investigated. In comparison of catalytic activities between the catalysts before and after regeneration, results showed that washing was the most effective regeneration method, and the sulfuric acid concentration of the washing solution was an important factor. Washing time directly affected catalyst regeneration efficiency and catalyst life. The regenerated TiO2-ZrO2 -CeO2 /ATS catalyst regained more than 90% NO conversion after being washed with 10 wt.% H2SO4 for 30 min.展开更多
Zr-doped-TiO2 loaded glass fiber（ZT/GF） composite photocatalysts with different Zr/Ti ratios were prepared with a sol–gel process. Zr4＋can replace Ti4＋in the TiO2 lattice, which is conducive to forming the anatas...Zr-doped-TiO2 loaded glass fiber（ZT/GF） composite photocatalysts with different Zr/Ti ratios were prepared with a sol–gel process. Zr4＋can replace Ti4＋in the TiO2 lattice, which is conducive to forming the anatase phase and reducing the calcination temperature. The glass fiber carrier was responsible for better dispersion and loading of Zr-doped-TiO2 particles, improving the applicability of the Zr-doped-TiO2. The ZT/GF photocatalysts were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, Fourier transform infrared spectroscopy（FT-IR）, ultraviolet–visible spectroscopy（UV–vis） and Barrett–Joyner–Halenda（BJH）. The performance of photocatalysts with different loading was evaluated in formaldehyde degradation under visible light at room temperature. ZT/GF0.2exhibited the highest activity, with a formaldehyde removal rate as high as 95.14% being observed, which is better than that of the photocatalyst particles alone. The stability of the catalyst was also tested, and ZT/GF exhibited excellent catalytic performance with 94.38%removal efficiency, even after seven uses.展开更多
In this paper, Fe-doped TiO_2 photocatalyst supported on hollow glass microbeads(Fe-TiO_2 /beads)is prepared by dip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(O...In this paper, Fe-doped TiO_2 photocatalyst supported on hollow glass microbeads(Fe-TiO_2 /beads)is prepared by dip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(OC_4H_9)_4] as the raw material. The phase structure, ingredient, morphologies, particle size and shell thickness of the products are characterized by X-ray powder diffraction(XRD), energy-dispersive spectroscopy(EDS) and field emission scanning electron microscope(FESEM). The feasibility of photocatylic degradation of Rhodamine B(Rh B) under illumination of UV-vis light is studied. The results show that the core-shell structure catalyst is composed of Fe-doped anatase TiO_2 and hollow glass microbeads, and the catalytic activity of the TiO_2 is markedly enhanced by Fe ion doping. The optimum concentration of Fe ion is 0.1%(molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. The presence of ferrum elements neither influences the transformation of anatase to rutile, nor creates new crystal phases. The possible mechanism of photocatalytic oxidation is also discussed.展开更多
The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morph...The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.展开更多
TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2-60% molar CeO2 ceramic target in Ar：O2=95：5 atmosphere.The structure,surf...TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2-60% molar CeO2 ceramic target in Ar：O2=95：5 atmosphere.The structure,surface composition,UV-visible spectra of the films were measured by scanning electron microscopy and X-ray diffraction,and X-ray photoelectron spectroscopy,respectively.The experimental results show that the films are amorphous,there are only Ti^4＋ and Ce^4＋ on the surface of the films,the obtained TiO2-CeO2 films shou a good uniformity and high densification,and the films deposited on the glass can shield ultraviolet light without significant absorpition of visible light,the films deposited on substrates at room temperature and 220℃ absorb UV effectively.展开更多
A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter ...A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter as nanoparticles with the formation of the SiO Ti bonds.The growth mechanism accounting for the formation of the TiO2 nanolayers was proposed.The morphology,composition,thermal insulation properties,and visible-near infrared(VIS-NIR)refl ectance of the HGMs/TiO2 composite hollow spheres were characterized.The VIS-NIR reflectance of the HGMs/TiO2 composite hollow spheres increased by more than 30%compared to raw HGMs.The thermal conductivity of the particles is 0.058 W/(m K).The result indicates that the VIS-NIR reflectance of the composite hollow spheres is strongly influenced by the coating of TiO2.The composite hollow spheres were used as the main functional filler to prepare the organic-inorganic composite coatings.The glass substrates coated by the organic-inorganic coatings had lower thermal conductivity and higher near infrared reflectivity.Therefore,the HGMs/TiO2 composite hollow spheres can reflect most of the solar energy and effectively keep out the heat as a thermal insulation coating for energy-saving constructions.展开更多
Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indica...Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own phases.As for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge bonds.With the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti bonds.Furthermore,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 laser.Therefore, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.展开更多
TiO 2/glass film photocatalysts have been prepared by a sol gel method with titanium tetrabutoxide as precursor, and used in photocatalytic degradation of 2,4 dichlorophenol(DCP) in aqueous solution. The experiments i...TiO 2/glass film photocatalysts have been prepared by a sol gel method with titanium tetrabutoxide as precursor, and used in photocatalytic degradation of 2,4 dichlorophenol(DCP) in aqueous solution. The experiments indicated that the TiO 2/glass film coated with five layers of TiO 2 sol in the case of higher pH value(≥10) or lower pH value(≤2) showed a higher catalytic activity, and the relationship between initial DCP concentration( c 0) and reaction rate( r 0) follows Langmuir Hinshelwood equation. The photocatalytic degradation kinetics of DCP( c 0≤0 5 mmol/L) is of first order kinetics.展开更多
基金Funded by the Natural Science Foundation of China (No. 50872001 and No. 50642038)the Scientific Research Foundation of Education Ministry of Anhui Province (No. 2005KJ224 and No. KJ2007B132)the Graduate Student Innovation Programs of Anhui University (No. 20072006)
文摘We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of （Sr, Bi, Si, Ta）-doped TiO2- based varistor ceramics sintered at 1 250℃ for 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, and 5.0 h, respectively. The samples were characterized by X-ray diffraction, breakdown voltage, and complex impedance. The results show that as the soaking time increases from 0.5 h to 5.0 h, the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases. We suggest that, considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics, the optimal soaking time is between 2.0 h and 3.0 h.
文摘This paper reports the formation and some properties of a new class of chalcohalide glasses in the As2Tef iodide systems. The As2Te3-Pb12, As2Te3-HgI2, As2Te3-CitI and As2Te3-AgI systems can form stable bulk glasses in wide composition regions ?and no bulk glass formation was found in the As2Te3-TH sys-tem. As2Te3-based glasses have glass transition tempera-
基金Project supported by National Natural Science Foundation of China(51272105,51172107,21106071)the New Teachers'Fund for Doctor Stations Sponsored by the Ministry of Education of China(20113221120004)+1 种基金the National Key Technology R&D Program of China(2012BAE01B03)the Supporting Program for Sci&Tech Research of Jiangsu Province of China(2011023)
文摘Larger amounts of alkalis, alkali earth metals and sulfides in flue gas from glass furnace were easier to deactivate selective catalytic reduction （SCR） catalyst compared to the flue gases from other stationary sources. Catalyst regeneration has been an emerging research topic for flue gas denitrification in glass furnace. Regeneration of the deactivated TiO2-ZrO2-CeO2 /Al2TiO 5 -TiO2-SiO2 （ATS） complex phase ceramics catalysts used for NH3 -SCR of NO x in glass furnace was studied in this work. Effects of regeneration methods, including washing with different aqueous solutions and sulfuric acid, thermal regeneration, thermal reduction regeneration, and thermal regeneration with SO2 , on catalytic performance were comparatively investigated. In comparison of catalytic activities between the catalysts before and after regeneration, results showed that washing was the most effective regeneration method, and the sulfuric acid concentration of the washing solution was an important factor. Washing time directly affected catalyst regeneration efficiency and catalyst life. The regenerated TiO2-ZrO2 -CeO2 /ATS catalyst regained more than 90% NO conversion after being washed with 10 wt.% H2SO4 for 30 min.
基金financially supported by the Project of Science and Technology Department of Jiangsu Province (BE2016769)the Natural Science Foundation of China (No. 51608261)+2 种基金Six talent peaks project in Jiangsu Province (2016)Open fund by Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials (KFK1503)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Zr-doped-TiO2 loaded glass fiber（ZT/GF） composite photocatalysts with different Zr/Ti ratios were prepared with a sol–gel process. Zr4＋can replace Ti4＋in the TiO2 lattice, which is conducive to forming the anatase phase and reducing the calcination temperature. The glass fiber carrier was responsible for better dispersion and loading of Zr-doped-TiO2 particles, improving the applicability of the Zr-doped-TiO2. The ZT/GF photocatalysts were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, Fourier transform infrared spectroscopy（FT-IR）, ultraviolet–visible spectroscopy（UV–vis） and Barrett–Joyner–Halenda（BJH）. The performance of photocatalysts with different loading was evaluated in formaldehyde degradation under visible light at room temperature. ZT/GF0.2exhibited the highest activity, with a formaldehyde removal rate as high as 95.14% being observed, which is better than that of the photocatalyst particles alone. The stability of the catalyst was also tested, and ZT/GF exhibited excellent catalytic performance with 94.38%removal efficiency, even after seven uses.
文摘In this paper, Fe-doped TiO_2 photocatalyst supported on hollow glass microbeads(Fe-TiO_2 /beads)is prepared by dip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(OC_4H_9)_4] as the raw material. The phase structure, ingredient, morphologies, particle size and shell thickness of the products are characterized by X-ray powder diffraction(XRD), energy-dispersive spectroscopy(EDS) and field emission scanning electron microscope(FESEM). The feasibility of photocatylic degradation of Rhodamine B(Rh B) under illumination of UV-vis light is studied. The results show that the core-shell structure catalyst is composed of Fe-doped anatase TiO_2 and hollow glass microbeads, and the catalytic activity of the TiO_2 is markedly enhanced by Fe ion doping. The optimum concentration of Fe ion is 0.1%(molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. The presence of ferrum elements neither influences the transformation of anatase to rutile, nor creates new crystal phases. The possible mechanism of photocatalytic oxidation is also discussed.
基金Projects(21171027,50872014) supported by the National Natural Science Foundation of ChinaProject(K1001020-11)supported by the Science and Technology Key Project of Changsha City,China
文摘The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.
文摘TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2-60% molar CeO2 ceramic target in Ar：O2=95：5 atmosphere.The structure,surface composition,UV-visible spectra of the films were measured by scanning electron microscopy and X-ray diffraction,and X-ray photoelectron spectroscopy,respectively.The experimental results show that the films are amorphous,there are only Ti^4＋ and Ce^4＋ on the surface of the films,the obtained TiO2-CeO2 films shou a good uniformity and high densification,and the films deposited on the glass can shield ultraviolet light without significant absorpition of visible light,the films deposited on substrates at room temperature and 220℃ absorb UV effectively.
文摘A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter as nanoparticles with the formation of the SiO Ti bonds.The growth mechanism accounting for the formation of the TiO2 nanolayers was proposed.The morphology,composition,thermal insulation properties,and visible-near infrared(VIS-NIR)refl ectance of the HGMs/TiO2 composite hollow spheres were characterized.The VIS-NIR reflectance of the HGMs/TiO2 composite hollow spheres increased by more than 30%compared to raw HGMs.The thermal conductivity of the particles is 0.058 W/(m K).The result indicates that the VIS-NIR reflectance of the composite hollow spheres is strongly influenced by the coating of TiO2.The composite hollow spheres were used as the main functional filler to prepare the organic-inorganic composite coatings.The glass substrates coated by the organic-inorganic coatings had lower thermal conductivity and higher near infrared reflectivity.Therefore,the HGMs/TiO2 composite hollow spheres can reflect most of the solar energy and effectively keep out the heat as a thermal insulation coating for energy-saving constructions.
文摘Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own phases.As for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge bonds.With the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti bonds.Furthermore,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 laser.Therefore, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.
文摘TiO 2/glass film photocatalysts have been prepared by a sol gel method with titanium tetrabutoxide as precursor, and used in photocatalytic degradation of 2,4 dichlorophenol(DCP) in aqueous solution. The experiments indicated that the TiO 2/glass film coated with five layers of TiO 2 sol in the case of higher pH value(≥10) or lower pH value(≤2) showed a higher catalytic activity, and the relationship between initial DCP concentration( c 0) and reaction rate( r 0) follows Langmuir Hinshelwood equation. The photocatalytic degradation kinetics of DCP( c 0≤0 5 mmol/L) is of first order kinetics.
