By sol-gel method and dip-coating technique,TiO2 particles were loaded to the surfaces of molecular sieve particles and porous Al2O3 beads,respectively.The XRD results indicated that TiO2 appeared on both supp...By sol-gel method and dip-coating technique,TiO2 particles were loaded to the surfaces of molecular sieve particles and porous Al2O3 beads,respectively.The XRD results indicated that TiO2 appeared on both supporting materials in anatase as nano-grade particle.Catalytic activities of the supported TiO2 photocatalysts were confirmed by degrading Rhodamine B in water.展开更多
ZnO/SiO\-2 and ZnO\|SiO\-2 catalysts were prepared by the impregnation and sol\|gel method, respectively. The characterization of the catalysts by XPS and FTIR indicated that much "free" zinc oxide and unrea...ZnO/SiO\-2 and ZnO\|SiO\-2 catalysts were prepared by the impregnation and sol\|gel method, respectively. The characterization of the catalysts by XPS and FTIR indicated that much "free" zinc oxide and unreacted Si\_OH existed on the surface of ZnO/SiO\-2 sample. As for ZnO\|SiO\-2 sol\|gel catalyst, the corresponding phenomena were not observed. The prepared samples were also used as the catalysts for decomposition of 2\|butanol. A high selectivity for dehydrogenation was observed over the supported catalyst. However, a high selectivity for dehydration was shown over the ZnO\|SiO\-2 sol\|gel catalyst. The opposite selectivity for dehydration or dehydrogenation observed over the two kinds of catalysts may be just because of the different surface structures of the catalysts.展开更多
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
文摘By sol-gel method and dip-coating technique,TiO2 particles were loaded to the surfaces of molecular sieve particles and porous Al2O3 beads,respectively.The XRD results indicated that TiO2 appeared on both supporting materials in anatase as nano-grade particle.Catalytic activities of the supported TiO2 photocatalysts were confirmed by degrading Rhodamine B in water.
文摘ZnO/SiO\-2 and ZnO\|SiO\-2 catalysts were prepared by the impregnation and sol\|gel method, respectively. The characterization of the catalysts by XPS and FTIR indicated that much "free" zinc oxide and unreacted Si\_OH existed on the surface of ZnO/SiO\-2 sample. As for ZnO\|SiO\-2 sol\|gel catalyst, the corresponding phenomena were not observed. The prepared samples were also used as the catalysts for decomposition of 2\|butanol. A high selectivity for dehydrogenation was observed over the supported catalyst. However, a high selectivity for dehydration was shown over the ZnO\|SiO\-2 sol\|gel catalyst. The opposite selectivity for dehydration or dehydrogenation observed over the two kinds of catalysts may be just because of the different surface structures of the catalysts.
文摘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.
