V-doped TiO2/AC supported catalysts were formed on the surface of active carbon(AC) by sol-gel method from ammonium metavanadate and tetrabutylorthotitanate,and characterized by X-ray diffraction(XRD) and UV-vis s...V-doped TiO2/AC supported catalysts were formed on the surface of active carbon(AC) by sol-gel method from ammonium metavanadate and tetrabutylorthotitanate,and characterized by X-ray diffraction(XRD) and UV-vis spectrophotometry.The photocatalytic activities of the supported catalysts were evaluated in photo-degradation of methyl orange and omethoate aqueous solutions,respectively.The results showed that both the rutile phase and anatase phase are formed.The supported catalyst showed the highest photocatalytic activity at the mass fraction of V in TiO2 of 1.5%.The band edges in UV-vis spectra of the V-doped TiO2/AC supported catalyst showed a red-shift compared with un-doped membrane;but there was no certain correlation between these red-shifts of band-edges and the photocatalytic efficiency of the supported catalyst.In photocatalytic degradation,electrons may be transferred directly from the reactant to the conductive band of V2O5 and so the mechanism of the degradation was changed.Electrons that transferred to the conductive band of V2O5 may be excited by irradiation to the conductive band of TiO2 and be captured by O2.However,they may also be transferred to the valence band of TiO2 and recombine with photogenerated holes.So a moderate amount of V in the supported catalyst may lead an increased the photocatalytic activity.展开更多
The nanocrystalline TiO2/activated carbon composite catalyst (TiO2/AC) was prepared through sol-gel method in isopropanol mixed with activated carbon (AC) in order to remove phenol from aqueous solution, The prepa...The nanocrystalline TiO2/activated carbon composite catalyst (TiO2/AC) was prepared through sol-gel method in isopropanol mixed with activated carbon (AC) in order to remove phenol from aqueous solution, The prepared-TiO2/AC was calcined at 400 ℃ and characterized by X-ray diffraction spectrometry (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and nitrogen adsorption-desorption by Brunauer-Emmett-Teller (BET) method. The XRD pattern indicated that the TiOJAC was in Anatase phase. TEM image showed that the crystallite size of TiOjAC was in the range of 7-9 nm. The SEM image of TiO2/AC showed that the activated carbon was homogeneity covered with TiO2 particles and was coated with TiO2-film spreading throughout the surface. The specific surface area from BET method was 441 m^2/g and adsorption capacity determined from adsorption isotherm was 5.0× 10^4 mg/g. The TiO2/AC calcined at 400 ℃ was used to remove phenol in aqueous solution under UV irradiation, which showed higher removal efficiency than TiO2 (Degussa-P25) and AC. The percentage of removal of 100 ppm phenol by 0.4 g of TiO2/AC in 4 h was 68.03%, due to both adsorption (54.14%) and photocatalytic degradation (13.88%) with rate constant of 0.1080 h^-1. The prepared TiO2/AC can be reused for the treatment of phenol for at least 3 times with 76% efficiency compared to the first photocatalytic run.展开更多
摘要V-doped TiO2/AC supported catalysts were formed on the surface of active carbon(AC) by sol-gel method from ammonium metavanadate and tetrabutylorthotitanate,and characterized by X-ray diffraction(XRD) and UV-vis spectrophotometry.The photocatalytic activities of the supported catalysts were evaluated in photo-degradation of methyl orange and omethoate aqueous solutions,respectively.The results showed that both the rutile phase and anatase phase are formed.The supported catalyst showed the highest photocatalytic activity at the mass fraction of V in TiO2 of 1.5%.The band edges in UV-vis spectra of the V-doped TiO2/AC supported catalyst showed a red-shift compared with un-doped membrane;but there was no certain correlation between these red-shifts of band-edges and the photocatalytic efficiency of the supported catalyst.In photocatalytic degradation,electrons may be transferred directly from the reactant to the conductive band of V2O5 and so the mechanism of the degradation was changed.Electrons that transferred to the conductive band of V2O5 may be excited by irradiation to the conductive band of TiO2 and be captured by O2.However,they may also be transferred to the valence band of TiO2 and recombine with photogenerated holes.So a moderate amount of V in the supported catalyst may lead an increased the photocatalytic activity.
摘要The nanocrystalline TiO2/activated carbon composite catalyst (TiO2/AC) was prepared through sol-gel method in isopropanol mixed with activated carbon (AC) in order to remove phenol from aqueous solution, The prepared-TiO2/AC was calcined at 400 ℃ and characterized by X-ray diffraction spectrometry (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and nitrogen adsorption-desorption by Brunauer-Emmett-Teller (BET) method. The XRD pattern indicated that the TiOJAC was in Anatase phase. TEM image showed that the crystallite size of TiOjAC was in the range of 7-9 nm. The SEM image of TiO2/AC showed that the activated carbon was homogeneity covered with TiO2 particles and was coated with TiO2-film spreading throughout the surface. The specific surface area from BET method was 441 m^2/g and adsorption capacity determined from adsorption isotherm was 5.0× 10^4 mg/g. The TiO2/AC calcined at 400 ℃ was used to remove phenol in aqueous solution under UV irradiation, which showed higher removal efficiency than TiO2 (Degussa-P25) and AC. The percentage of removal of 100 ppm phenol by 0.4 g of TiO2/AC in 4 h was 68.03%, due to both adsorption (54.14%) and photocatalytic degradation (13.88%) with rate constant of 0.1080 h^-1. The prepared TiO2/AC can be reused for the treatment of phenol for at least 3 times with 76% efficiency compared to the first photocatalytic run.