A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}/n(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared wer...A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}/n(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO 2) as the model reactant, showed that TiO 2-SiO 2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO 2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity.展开更多
（ CdS/ TiO2 ）/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocat...（ CdS/ TiO2 ）/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% （ molar ratio ）, the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.展开更多
The influence of the baked temperature for TiO 2 ultrafine particles on the photocatalytic oxidation reaction of SO 2 was investigated. The photocatalytic activity of TiO 2 baked at 320 ℃ is higher than that at other...The influence of the baked temperature for TiO 2 ultrafine particles on the photocatalytic oxidation reaction of SO 2 was investigated. The photocatalytic activity of TiO 2 baked at 320 ℃ is higher than that at other temperatures(480 ℃, 550 ℃). It may be explained by the surface state of TiO 2, increasing the content of surface hydroxyl is helpful to enhance the photocatalytic activity. According to the experimental results, the first order kinetic reaction and the mechanism of the reaction were suggested, also the rate constants and half life time were reported.展开更多
The washed and dried porous silica gel was soaked in water glass of moderate viscosity, then mixed with nanometer TiO 2, stired until TiO 2 has been uniformly distributed on the porous silica gel. After dried naturall...The washed and dried porous silica gel was soaked in water glass of moderate viscosity, then mixed with nanometer TiO 2, stired until TiO 2 has been uniformly distributed on the porous silica gel. After dried naturally, it was calcined at 300 ℃ for 1 h to give the immobilized nanometer TiO 2 which was mechanically and chemically stable, and can be reused. Under the illumination of high pressure Hg lamp, the X 3B dye could be degraded almost quantitatively(98%) in a solution containing the photocatalyst, Fe 3+ and H 2O 2 with bubbling of air.展开更多
基金Supported by the National Natural Science Foundation of China(No.2 0 2 770 15 )
文摘A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}/n(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO 2) as the model reactant, showed that TiO 2-SiO 2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO 2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity.
基金Funded by Special Fund of Education Department of ShaanxiProvince(No.03JK144)
文摘（ CdS/ TiO2 ）/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% （ molar ratio ）, the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.
文摘The influence of the baked temperature for TiO 2 ultrafine particles on the photocatalytic oxidation reaction of SO 2 was investigated. The photocatalytic activity of TiO 2 baked at 320 ℃ is higher than that at other temperatures(480 ℃, 550 ℃). It may be explained by the surface state of TiO 2, increasing the content of surface hydroxyl is helpful to enhance the photocatalytic activity. According to the experimental results, the first order kinetic reaction and the mechanism of the reaction were suggested, also the rate constants and half life time were reported.
文摘The washed and dried porous silica gel was soaked in water glass of moderate viscosity, then mixed with nanometer TiO 2, stired until TiO 2 has been uniformly distributed on the porous silica gel. After dried naturally, it was calcined at 300 ℃ for 1 h to give the immobilized nanometer TiO 2 which was mechanically and chemically stable, and can be reused. Under the illumination of high pressure Hg lamp, the X 3B dye could be degraded almost quantitatively(98%) in a solution containing the photocatalyst, Fe 3+ and H 2O 2 with bubbling of air.
