N-doped nano-crystalline TiO2 powders have been synthesized by the sol-gel method.The shape and crystal structure of the resulting N-doped TiO2 were investigated by X-ray Photoelectron Spectroscopy(XPS),X-ray spectros...N-doped nano-crystalline TiO2 powders have been synthesized by the sol-gel method.The shape and crystal structure of the resulting N-doped TiO2 were investigated by X-ray Photoelectron Spectroscopy(XPS),X-ray spectroscopy(XRD),Transmission Electron Microscopy(TEM)and UV-vis reflection spectrum.The results showed that doping TiO2 with nitrogen can lower its band gap and apparently shift its optical response to the visible region.Under the visible light(λ】420 nm)irradiation,the MC-LR was degraded by the synthesized N-TiO2 nano-material.The variation of MC-LR amount and its intermediates were detected by high performance liquid chromatography(HPLC)and LC-MS,respectively.The mineralization of MC-LR was determined by total organic carbon(TOC)analysis.Simultaneously,transient oxidative species generated during photocatalysis were tracked by electron spin resonance(ESR)and Peroxidase method.All these results indicated that visible-light excited N-TiO2 can activate molecular oxygen and thereby achieve degradation of MC-LR completely within 14 h.The removal of 59%of TOC was achieved after 20 h irradiation.The major oxidative species in the system were hydroxyl radical(·OH)and H2O2.13 Kinds of intermediates were primarily identified in the process.Based on these results,a reasonable conclusion was drawn for the degradation of MC-LR wherein its four positions are easy to be attacked by the photo-generated OH radical followed by the hydrolyzation of peptides.展开更多
A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnP...A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2.X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst.The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions.The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (COD Cr) assays and electron spin resonance (ESR),respectively.RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation.Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% COD Cr removal occurred after 24 h of irradiation.ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O-·2) generated in the system.展开更多
基金supported by the National Natural Science Foundation of China(20877048)the Major State Basic Research Development Program of China(2008CB417206)The Plan of Scientific and Technological Innovation Team of Outstanding Young in Universities of Hubei Province(T200703)
文摘N-doped nano-crystalline TiO2 powders have been synthesized by the sol-gel method.The shape and crystal structure of the resulting N-doped TiO2 were investigated by X-ray Photoelectron Spectroscopy(XPS),X-ray spectroscopy(XRD),Transmission Electron Microscopy(TEM)and UV-vis reflection spectrum.The results showed that doping TiO2 with nitrogen can lower its band gap and apparently shift its optical response to the visible region.Under the visible light(λ】420 nm)irradiation,the MC-LR was degraded by the synthesized N-TiO2 nano-material.The variation of MC-LR amount and its intermediates were detected by high performance liquid chromatography(HPLC)and LC-MS,respectively.The mineralization of MC-LR was determined by total organic carbon(TOC)analysis.Simultaneously,transient oxidative species generated during photocatalysis were tracked by electron spin resonance(ESR)and Peroxidase method.All these results indicated that visible-light excited N-TiO2 can activate molecular oxygen and thereby achieve degradation of MC-LR completely within 14 h.The removal of 59%of TOC was achieved after 20 h irradiation.The major oxidative species in the system were hydroxyl radical(·OH)and H2O2.13 Kinds of intermediates were primarily identified in the process.Based on these results,a reasonable conclusion was drawn for the degradation of MC-LR wherein its four positions are easy to be attacked by the photo-generated OH radical followed by the hydrolyzation of peptides.
基金supported by the National Natural Science Foundation of China(20877048)the National Basic Research Program of China(2008CB417206)the Innovation Group Project of Hubei Provincial Natural Science Foundation(2009CDA020)
文摘A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2.X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst.The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions.The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (COD Cr) assays and electron spin resonance (ESR),respectively.RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation.Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% COD Cr removal occurred after 24 h of irradiation.ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O-·2) generated in the system.
