[Zn(CH3COO)2 + PVP]/[C2H5O)4Si + PVP]/[SnCl4 + PVP]/[Ti(OC4H9)4 + CH3COOH + PVP] precursor composite fibers have been fabricated through self-made electrospinning equipment via electrospinning tech-nique. ZnO/SiO2/SnO...[Zn(CH3COO)2 + PVP]/[C2H5O)4Si + PVP]/[SnCl4 + PVP]/[Ti(OC4H9)4 + CH3COOH + PVP] precursor composite fibers have been fabricated through self-made electrospinning equipment via electrospinning tech-nique. ZnO/SiO2/SnO2/TiO2 composite nanofibers were obtained by calcination of the relevant precursor composite fibers. The samples were characterized by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). TG-DTA analysis reveals that solvents, organic compounds and inorganic in the precursor composite fibers are decomposed and volatilized totally, and the mass of the samples kept constant when sintering temperature was above 900?C, and the total mass loss percentage is 88%. XRD results show that the precursor composite fibers are amorphous in structure, and pure phase ZnO/SiO2/SnO2/TiO2 com-posite nanofibers are obtained by calcination of the relevant precursor composite fibers. FTIR analysis manifests that pure inorganic oxides are formed. SEM analysis indicates that the width of the precursor composite fibers is ca. 1.485 ± 0.043 μm. The width of the ZnO/SiO2/SnO2/TiO2 composite nanofibers is ca. 1145.098 ± 68.093 nm.展开更多
TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations ...TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.展开更多
Supported loaded semiconductors （MoO3,ZnO）-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorpti...Supported loaded semiconductors （MoO3,ZnO）-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.展开更多
Mixed oxide photocatalysts, ZnO-Zn2SnO4 （ZnO-ZTO） nanowires with different sizes were prepared by a simple thermal evaporation method. The ZnO-ZTO nanowires were characterized with a scanning electron microscope, X-...Mixed oxide photocatalysts, ZnO-Zn2SnO4 （ZnO-ZTO） nanowires with different sizes were prepared by a simple thermal evaporation method. The ZnO-ZTO nanowires were characterized with a scanning electron microscope, X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive spectrom- eter, and X-ray photoelectron spectra. The photocatalytic activity of the ZnO-ZTO mixed nanowires were studied by observing the photodegradation behaviors of methyl orange aqueous solution. The results suggest that the ZnO-ZTO mixed oxide nanowires have a higher photocatalytic activity than pure ZnO and Zn2SnO4 nanowires. The photocatalyst concentration in the solution distinctly affects the degradation rate, and our results show that higher photodegradation efficiency can be achieved with a smaller amount of ZnO-ZTO nanowire catalyst, as compared to the pure ZnO and ZTO nanowires. Moreover, the photocatalytic activity can also be enhanced by reducing the average diameter of the nanowires. The activity of pure ZnO and ZTO nanowires are also enhanced by physically mixing them. These results can be explained by the synergism between the two semiconductors.展开更多
以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti ...以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti O2 做了简单对比 .结果表明 :所制 Ti O2 / Sn O2 样品为包覆型结构 ,由锐钛矿型 Ti O2 金红石型 Sn O2 组成 ,与 Sn O2 及 Ti O2 晶体粉末相比所制 Ti O2 / Sn O2 包覆粒子光催化活性得到明显提高 .展开更多
The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface wit...The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface within 3 s and its dynamic contact angles can be expressed by a power law θ d= k(t+a) -n with the n value 0.98. Less than 50%(molar fraction) SiO 2 addition can accelerate the dynamic water spreading rate on the TiO 2 SiO 2 films and the optimum molar fraction of SiO 2 amount corresponding to as annealed, air plasma, and UV irradiation treatment process is 15%, 10% and 20%, respectively.展开更多
文摘[Zn(CH3COO)2 + PVP]/[C2H5O)4Si + PVP]/[SnCl4 + PVP]/[Ti(OC4H9)4 + CH3COOH + PVP] precursor composite fibers have been fabricated through self-made electrospinning equipment via electrospinning tech-nique. ZnO/SiO2/SnO2/TiO2 composite nanofibers were obtained by calcination of the relevant precursor composite fibers. The samples were characterized by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). TG-DTA analysis reveals that solvents, organic compounds and inorganic in the precursor composite fibers are decomposed and volatilized totally, and the mass of the samples kept constant when sintering temperature was above 900?C, and the total mass loss percentage is 88%. XRD results show that the precursor composite fibers are amorphous in structure, and pure phase ZnO/SiO2/SnO2/TiO2 com-posite nanofibers are obtained by calcination of the relevant precursor composite fibers. FTIR analysis manifests that pure inorganic oxides are formed. SEM analysis indicates that the width of the precursor composite fibers is ca. 1.485 ± 0.043 μm. The width of the ZnO/SiO2/SnO2/TiO2 composite nanofibers is ca. 1145.098 ± 68.093 nm.
文摘TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.
文摘Supported loaded semiconductors （MoO3,ZnO）-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.
基金ACKNOWLEDGMENTS This work was supported by the National Natu- ral Science Foundation of China （No.50121202 and No.90406009）, the National Research Foundation for the Doctoral Program of the Ministry of Education （No.20040358059） and the Natural Basic Program of China （No.2006CB922002）.
文摘Mixed oxide photocatalysts, ZnO-Zn2SnO4 （ZnO-ZTO） nanowires with different sizes were prepared by a simple thermal evaporation method. The ZnO-ZTO nanowires were characterized with a scanning electron microscope, X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive spectrom- eter, and X-ray photoelectron spectra. The photocatalytic activity of the ZnO-ZTO mixed nanowires were studied by observing the photodegradation behaviors of methyl orange aqueous solution. The results suggest that the ZnO-ZTO mixed oxide nanowires have a higher photocatalytic activity than pure ZnO and Zn2SnO4 nanowires. The photocatalyst concentration in the solution distinctly affects the degradation rate, and our results show that higher photodegradation efficiency can be achieved with a smaller amount of ZnO-ZTO nanowire catalyst, as compared to the pure ZnO and ZTO nanowires. Moreover, the photocatalytic activity can also be enhanced by reducing the average diameter of the nanowires. The activity of pure ZnO and ZTO nanowires are also enhanced by physically mixing them. These results can be explained by the synergism between the two semiconductors.
文摘以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti O2 做了简单对比 .结果表明 :所制 Ti O2 / Sn O2 样品为包覆型结构 ,由锐钛矿型 Ti O2 金红石型 Sn O2 组成 ,与 Sn O2 及 Ti O2 晶体粉末相比所制 Ti O2 / Sn O2 包覆粒子光催化活性得到明显提高 .
文摘The dynamic wetting of water spreading on TiO 2 and TiO 2 SiO 2 films prepared by sol gel method and subsequently treated by air plasma and UV irradiation was investigated. Water completely spread on TiO 2 surface within 3 s and its dynamic contact angles can be expressed by a power law θ d= k(t+a) -n with the n value 0.98. Less than 50%(molar fraction) SiO 2 addition can accelerate the dynamic water spreading rate on the TiO 2 SiO 2 films and the optimum molar fraction of SiO 2 amount corresponding to as annealed, air plasma, and UV irradiation treatment process is 15%, 10% and 20%, respectively.
