Er3＋-doped TiO2-SiO2 powders are prepared by the sol-gel method, and they are characterized by high resolution transmission electron microscopy （HR-TEM）, X-ray diffraction （XRD） spectra, and Raman spectra of the ...Er3＋-doped TiO2-SiO2 powders are prepared by the sol-gel method, and they are characterized by high resolution transmission electron microscopy （HR-TEM）, X-ray diffraction （XRD） spectra, and Raman spectra of the samples. It is shown that the TiO2 nanocrystals are surrounded by an SiO2 glass matrix. The photoluminescence （PL） spectra are recorded at room temperature. A strong green luminescence and less intense red emission are observed in the samples when they are excited at 325 nm. The intensity of the emission, which is related to the defect states, is strongest at the annealing temperature of 800℃. The PL intensity of Er3＋ ions increases with increasing Ti/Si ratio due to energy transfer between nano-TiO2 particles and Er3＋ ions.展开更多
In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface c...In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.展开更多
TiO2-SiO2 thin films have been prepared on slide glass substrates by sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle ...TiO2-SiO2 thin films have been prepared on slide glass substrates by sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle of water, the microstructure, the transmittance, the photocatalytic activity and the specific surface area . The results showed that 10mol% of SiO2 additive was the most effective for decreasing contact angle of water. The SiO2 additive of less than 30mol% has a suppressive effect on the crystal growth of anatase in calcinations, resulting in a large surface area. Consequently, the super-hydrophilicity was improved.展开更多
The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed...The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and unstable activity. Depending on the calcination temperature, one, two, or three of the following Ni-containing species, NiO, Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction （TPR） and X-ray diffraction （XRD） results. Their reducibility decreased in the sequence： NiO〉Ni2.44Ti0.72Si0.07O4〉NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ~C were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.展开更多
TiO2-SiO2 hybrid materials containing Eu^3＋ ions were prepared via sol-gel method. Upon the introduction of TiO2, the emission intensity and the average decay time increase, revealing that the incorporation of TiO2 c...TiO2-SiO2 hybrid materials containing Eu^3＋ ions were prepared via sol-gel method. Upon the introduction of TiO2, the emission intensity and the average decay time increase, revealing that the incorporation of TiO2 can reduce the extent of the Eu^3＋ clusters. At the same time, the intensity ratio of ^5D0→^7F2 to ^5D0→^7F1 increases as the TiO2 concentration increases, indicating the formation of Eu^3＋ - O^2- - Ti^4＋ bonding. Moreover, the influence of the ion Eu^3 ＋ concentration on the luminescence properties and the R value were investigated.展开更多
TiO2-SiO2 composite films were produced on commercially pure titanium （CP-Ti） substrate by a sol-gel method to in- vestigate the behavior of sol aging time and its potential effects on the structural and electrochem...TiO2-SiO2 composite films were produced on commercially pure titanium （CP-Ti） substrate by a sol-gel method to in- vestigate the behavior of sol aging time and its potential effects on the structural and electrochemical properties of composite coatings. Anatase-TiO2 and quartz-SiO2 peaks were observed on all composite coated samples according to XRD results. It was observed that the average grain size increased with sol aging time. Also, the average smallest grain size was seen at composite coatings prepared from unaged sol according to the width of the peaks. Electrochemical behavior of coated samples was mainly investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy （EIS） in Simulated Body Fluid （SBF） solution. In corrosion tests, the composite coatings showed better anti-corrosion behavior than that of uncoated samples. In addition, the corrosion properties of the composite films were considerably affected by sol aging time. Corrosion resistance of coatings decreased with increasing aging time and the best result was obtained from composite coatings prepared from unaged sol.展开更多
基金Project supported by the Key Science and Technology Program of Henan Province of China (Grant Nos. 102102210448 and 102102210452)the Scientific Research Fundation of the Education Department of Henan Province,China (Grant No. 2010A140011)
文摘Er3＋-doped TiO2-SiO2 powders are prepared by the sol-gel method, and they are characterized by high resolution transmission electron microscopy （HR-TEM）, X-ray diffraction （XRD） spectra, and Raman spectra of the samples. It is shown that the TiO2 nanocrystals are surrounded by an SiO2 glass matrix. The photoluminescence （PL） spectra are recorded at room temperature. A strong green luminescence and less intense red emission are observed in the samples when they are excited at 325 nm. The intensity of the emission, which is related to the defect states, is strongest at the annealing temperature of 800℃. The PL intensity of Er3＋ ions increases with increasing Ti/Si ratio due to energy transfer between nano-TiO2 particles and Er3＋ ions.
基金This work was supported by the National Natural Science Foundation of China(No.50081001)the Education Department Project of Liaoning Province(No.202073425).
文摘In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.
基金Funded by Key Scientific and Technological Items of the Ministry of Education (No.99087) .
文摘TiO2-SiO2 thin films have been prepared on slide glass substrates by sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle of water, the microstructure, the transmittance, the photocatalytic activity and the specific surface area . The results showed that 10mol% of SiO2 additive was the most effective for decreasing contact angle of water. The SiO2 additive of less than 30mol% has a suppressive effect on the crystal growth of anatase in calcinations, resulting in a large surface area. Consequently, the super-hydrophilicity was improved.
文摘The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and unstable activity. Depending on the calcination temperature, one, two, or three of the following Ni-containing species, NiO, Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction （TPR） and X-ray diffraction （XRD） results. Their reducibility decreased in the sequence： NiO〉Ni2.44Ti0.72Si0.07O4〉NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ~C were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.
文摘TiO2-SiO2 hybrid materials containing Eu^3＋ ions were prepared via sol-gel method. Upon the introduction of TiO2, the emission intensity and the average decay time increase, revealing that the incorporation of TiO2 can reduce the extent of the Eu^3＋ clusters. At the same time, the intensity ratio of ^5D0→^7F2 to ^5D0→^7F1 increases as the TiO2 concentration increases, indicating the formation of Eu^3＋ - O^2- - Ti^4＋ bonding. Moreover, the influence of the ion Eu^3 ＋ concentration on the luminescence properties and the R value were investigated.
文摘TiO2-SiO2 composite films were produced on commercially pure titanium （CP-Ti） substrate by a sol-gel method to in- vestigate the behavior of sol aging time and its potential effects on the structural and electrochemical properties of composite coatings. Anatase-TiO2 and quartz-SiO2 peaks were observed on all composite coated samples according to XRD results. It was observed that the average grain size increased with sol aging time. Also, the average smallest grain size was seen at composite coatings prepared from unaged sol according to the width of the peaks. Electrochemical behavior of coated samples was mainly investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy （EIS） in Simulated Body Fluid （SBF） solution. In corrosion tests, the composite coatings showed better anti-corrosion behavior than that of uncoated samples. In addition, the corrosion properties of the composite films were considerably affected by sol aging time. Corrosion resistance of coatings decreased with increasing aging time and the best result was obtained from composite coatings prepared from unaged sol.
