A series of TiO 2-MoO 3 nano-composite photocatalysts were prepared by supercritical fluid dry method(SCFD) and an impregnation technique with TiCl 4 and (NH 4) 6Mo 7O 24 ·4H 2O as the starting materia...A series of TiO 2-MoO 3 nano-composite photocatalysts were prepared by supercritical fluid dry method(SCFD) and an impregnation technique with TiCl 4 and (NH 4) 6Mo 7O 24 ·4H 2O as the starting materials. The catalysts were characterized by the means of XRD, TEM and UV-Vis. Methyl orange was used as model compound for the evaluation of their catalytic activities. The results indicated that the photo-catalyst prepared by SCFD had the advantages of small size(12.84 nm), narrow distribution and good dispersivity. The presence of small amount of Mo in composite catalyst gives rise to the red shift of its absorbance wavelength, decrease of its energy gap and increase of the utility of visible light. Furthermore, higher surface acidity of the photo-catalyst was obtained as the result of the addition of MoO 3. Compared with pure TiO 2, the catalytic activity of the TiO 2-MoO 3 nano-composite photo-catalyst was improved significantly. As the doping concentration of the composite catalysts was controlled at 0.6%(molar percentage), 100% degradation of methyl orange was achieved with in 1.2 h irradiation time.展开更多
Ti-Ce, Ti-Si binary and Ti-Ce-Si ternary novel nanocomposite oxide photocatalysts were prepared with cheap inorganic salts TiCI4, Na2SiO3·9H2O and Ce（NO3）3·6H2O as precursors by supercritical fluid drying ...Ti-Ce, Ti-Si binary and Ti-Ce-Si ternary novel nanocomposite oxide photocatalysts were prepared with cheap inorganic salts TiCI4, Na2SiO3·9H2O and Ce（NO3）3·6H2O as precursors by supercritical fluid drying （SCFD） technology. The catalysts were characterized by means of XRD and TEM. The particle size of nanocomposite oxide photocatalysts synthesized by SCFD method is about 6 - 11 nm, which is smaller than those obtained by common drying method （CD）. The phase transformation from anatase to rutile was inhibited by SCFD technology. The peaks of SiO2 and CeO2 in XRD patterns indicate that a SiO2 amorphorous phase exists in all the samples and CeO2 is well dispersed on the surface of TiO2. The orthogonal test was designed to optimize the preparing conditions. It is found that ceria dop;.ng enhances the photocatalyric activity markedly, and the optimum doping of CeO2 is 0.1%. The thermal stability of photocatalyst can be improved ; the growth of particle-size and the decrease of surface area can be prohibited by doping of SlOe. Heat-treatment is a necessary factor to induce chemistry change of Ti-Si surface. The optimum heat-treating temperature is 600℃. A novel and efficient Ti-Ce-Si ternary nanocomposite was prepared by SCFI） method with strong thermal stability and high photoactivity in the photodegratation of phenol.展开更多
TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characteri...TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characterized by means of XRD, TEM and FTIR. The results show that SCFD can give rise to the direct synthesis of the anatase TiO_2-CeO_2,and the particle size is 6～11 nm under 500 ℃ thermal-treated,smaller than that by common drying (CD). The phase transformation from anatase to rutile is inhibited by supercritical fluid drying technology. The peak of CeO_2 is not observed in XRD patterns,Ce-O band vibration was present in FTIR spectrum,which indicates that CeO_2 is well dispersed on the surface of TiO_2.展开更多
A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination ...A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.展开更多
In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive...In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive a biogas dry reforming reactor in order to produce H<sub>2</sub> as a fuel for SOFC, in such as system. The aim of this study is to clarify the impact of climate data on the performance of solar collector with various sizes/designs. The temperature of heat transfer fluid produced by the solar collector is calculated by adopting the climate data for Nagoya city in Japan in 2021. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor and the power generated by SOFC were simulated. The results show the temperature of heat transfer fluid (T<sub>fb</sub>) and T<sub>fb</sub> ratio (a) based on the length of absorber (dx) = 1 m have a peak near the noon following the trend of solar intensity (I). Results also revealed that a increases with increase in dx. It is found that the differences of T<sub>fb</sub> and a between dx = 2 m and dx = 3 m are larger than those between dx = 1 m and dx = 2 m. It is revealed that T<sub>fb</sub> and a are higher in spring and summer. dx = 4 m is the optimum length of solar absorber. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor as well as the power generated by SOFC is the highest in August, resulting that it is prefer to produce H<sub>2</sub> and to generate SOFC in summer.展开更多
文摘A series of TiO 2-MoO 3 nano-composite photocatalysts were prepared by supercritical fluid dry method(SCFD) and an impregnation technique with TiCl 4 and (NH 4) 6Mo 7O 24 ·4H 2O as the starting materials. The catalysts were characterized by the means of XRD, TEM and UV-Vis. Methyl orange was used as model compound for the evaluation of their catalytic activities. The results indicated that the photo-catalyst prepared by SCFD had the advantages of small size(12.84 nm), narrow distribution and good dispersivity. The presence of small amount of Mo in composite catalyst gives rise to the red shift of its absorbance wavelength, decrease of its energy gap and increase of the utility of visible light. Furthermore, higher surface acidity of the photo-catalyst was obtained as the result of the addition of MoO 3. Compared with pure TiO 2, the catalytic activity of the TiO 2-MoO 3 nano-composite photo-catalyst was improved significantly. As the doping concentration of the composite catalysts was controlled at 0.6%(molar percentage), 100% degradation of methyl orange was achieved with in 1.2 h irradiation time.
文摘Ti-Ce, Ti-Si binary and Ti-Ce-Si ternary novel nanocomposite oxide photocatalysts were prepared with cheap inorganic salts TiCI4, Na2SiO3·9H2O and Ce（NO3）3·6H2O as precursors by supercritical fluid drying （SCFD） technology. The catalysts were characterized by means of XRD and TEM. The particle size of nanocomposite oxide photocatalysts synthesized by SCFD method is about 6 - 11 nm, which is smaller than those obtained by common drying method （CD）. The phase transformation from anatase to rutile was inhibited by SCFD technology. The peaks of SiO2 and CeO2 in XRD patterns indicate that a SiO2 amorphorous phase exists in all the samples and CeO2 is well dispersed on the surface of TiO2. The orthogonal test was designed to optimize the preparing conditions. It is found that ceria dop;.ng enhances the photocatalyric activity markedly, and the optimum doping of CeO2 is 0.1%. The thermal stability of photocatalyst can be improved ; the growth of particle-size and the decrease of surface area can be prohibited by doping of SlOe. Heat-treatment is a necessary factor to induce chemistry change of Ti-Si surface. The optimum heat-treating temperature is 600℃. A novel and efficient Ti-Ce-Si ternary nanocomposite was prepared by SCFI） method with strong thermal stability and high photoactivity in the photodegratation of phenol.
文摘TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characterized by means of XRD, TEM and FTIR. The results show that SCFD can give rise to the direct synthesis of the anatase TiO_2-CeO_2,and the particle size is 6～11 nm under 500 ℃ thermal-treated,smaller than that by common drying (CD). The phase transformation from anatase to rutile is inhibited by supercritical fluid drying technology. The peak of CeO_2 is not observed in XRD patterns,Ce-O band vibration was present in FTIR spectrum,which indicates that CeO_2 is well dispersed on the surface of TiO_2.
基金The authors thank the National Natural Scir nce Foun-dation of China(No.20076004)the National Development Project of High Technology(No.2001AA322030)the Doctoral Program of Higher Education(No.2000001005)for the financial support of this project.
文摘A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.
文摘In this paper, an energy system consisting of solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) has been proposed. The heat produced from the concentrating solar collector is used to drive a biogas dry reforming reactor in order to produce H<sub>2</sub> as a fuel for SOFC, in such as system. The aim of this study is to clarify the impact of climate data on the performance of solar collector with various sizes/designs. The temperature of heat transfer fluid produced by the solar collector is calculated by adopting the climate data for Nagoya city in Japan in 2021. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor and the power generated by SOFC were simulated. The results show the temperature of heat transfer fluid (T<sub>fb</sub>) and T<sub>fb</sub> ratio (a) based on the length of absorber (dx) = 1 m have a peak near the noon following the trend of solar intensity (I). Results also revealed that a increases with increase in dx. It is found that the differences of T<sub>fb</sub> and a between dx = 2 m and dx = 3 m are larger than those between dx = 1 m and dx = 2 m. It is revealed that T<sub>fb</sub> and a are higher in spring and summer. dx = 4 m is the optimum length of solar absorber. The amount of H<sub>2</sub> produced from the biogas dry reforming reactor as well as the power generated by SOFC is the highest in August, resulting that it is prefer to produce H<sub>2</sub> and to generate SOFC in summer.
