Photocatalytic degradation of phenol selected as model compound of organic pollutant had been investigated in aqueous titanium dioxide （TiO2） dispersion under UV irradiation. The effects of various parameters such a...Photocatalytic degradation of phenol selected as model compound of organic pollutant had been investigated in aqueous titanium dioxide （TiO2） dispersion under UV irradiation. The effects of various parameters such as pH, catalyst concentration, phenol concentration, anions, metal ions, electron acceptors, and surfactants on the photocatalytic degradation of phenol were investigated. The degradation kinetics was determined by the change in phenol concentration employing UV-Vis spectrometry as a function of irradiation time. The degradation kinetics of phenol follows pseudo first-order kinetics. The results showed a significant dependence of the photocatalytic degradation of phenol on the functional parameters. The probable promising roles of the additives on the degradation process were discussed.展开更多
Highly photocatalytically active cobalt-doped ZnO （ZnO：Co） nanorods have been prepared by a facile hydrothermal process. X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering and UV-vis diffuse refl...Highly photocatalytically active cobalt-doped ZnO （ZnO：Co） nanorods have been prepared by a facile hydrothermal process. X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering and UV-vis diffuse reflectance spectroscopy confirmed that the dopant ions substitute for some of the lattice zinc ions, and furthermore, that Co〉 and Co〉 ions coexist. The as-prepared ZnO：Co samples have an extended light absorption range compared with pure ZnO and showed highly efficient photocatalytic activity, only requiring 60 rain to decompose -93% of alizarin red dye under visible light irradiation （λ 〉 420 nm）, The photophysical mechanism of the visible photocatalytic activity was investigated with the help of surface photovoltage spectroscopy. The results indicated that a strong electronic interaction between the Co and ZnO was present, and that the incorporation of Co promoted the charge separation and enhanced the charge transfer ability and, at the same time, effectively inhibited the recombination of photogenerated charge carriers in ZnO, resulting in high visible light photocatalytic activity.展开更多
The solar-driven catalytic conversion of CO2 to useful chemical fuels is regarded as an environmentally friendly approach to reduce the consumption of fossil fuels and mitigate the greenhouse effect.However,it is high...The solar-driven catalytic conversion of CO2 to useful chemical fuels is regarded as an environmentally friendly approach to reduce the consumption of fossil fuels and mitigate the greenhouse effect.However,it is highly intriguing and challenging to promote the selectivity and efficiency of visible-light-responsive photocatalysts that favor the adsorption of CO2 in photoreduction processes.In this work,three-dimensional hierarchical Cd0.8Zn0.2S flowers(C8Z2S-F)with ultrathin petals were successfully synthesized through an in-situ self-assembly growth process using sodium citrate as a morphology director.The flower-like Cd0.8Zn0.2S solid solution exhibited remarkable photocatalytic performance in the reduction of CO2,generating CO up to 41.4μmol g^−1 under visible-light illumination for 3 h;this was nearly three times greater than that of Cd0.8Zn0.2S nanoparticles(C8Z2S-NP)(14.7μmol g^−1).Particularly,a comparably high selectivity of 89.9%for the conversion of CO2 to CO,with a turnover number of 39.6,was obtained from the solar-driven C8Z2S-F system in the absence of any co-catalyst or sacrificial agent.Terahertz time-domain spectroscopy indicated that the introduction of flower structures enhanced the light-harvesting capacity of C8Z2S-F.The in situ diffuse reflectance infrared Fourier transform spectroscopy unveiled the existence of surface-adsorbed species and the conversion of photoreduction intermediates during the photocatalytic process.Empirical characterizations and predictions of the photocatalytic mechanism demonstrated that the flower-like Cd0.8Zn0.2S solid solution possessed desirable CO2 adsorption properties and an enhanced charge-transfer capability,thus providing a highly effective photocatalytic reduction of CO2.展开更多
The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible l...The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible light irradiation,and a series of analytical techniques such as XRD,SEM,FTIR,TG-DSC,XPS,UV-vis-DRS and Raman spectroscopy were used to characterize the morphology,structure and optical properties of the photocatalysts.It is found that the anatase TiO2 was formed in all photocatalysts.Mn4+might incorporate into the lattice structure of TiO2 and partially replace Ti4+,thus causing the defects in the crystal structure and the broadening of the spectral response range of TiO2.At the same time,TiO2 particles were dispersed on the surface of the sepiolite,which immobilized TiO2 particles with sepiolite via the bond of Ti-O-Si.Mn-TiO2/sepiolite calcined at 400°C exhibits the highest photocatalytic activity and the degradation rate of direct fast emerald green is up to 98.13%.Meanwhile,it also shows good stability and universality.展开更多
Nanoflower-like ZnO-C_(3)N_(4) thin film with a porous net structure was successfully synthesized by a simple chemical corrosion method.The prepared ZnOC_(3)N_(4) thin films presented remarkable photocatalytic activit...Nanoflower-like ZnO-C_(3)N_(4) thin film with a porous net structure was successfully synthesized by a simple chemical corrosion method.The prepared ZnOC_(3)N_(4) thin films presented remarkable photocatalytic activities for the degradation of methyl orange under visible light irradiation,and more than 90%methyl orange was removed from water by ZnO-C_(3)N_(4) composite.Meanwhile,the ZnO-C_(3)N_(4) composite presented an enhanced photocatalytic stability.The loading content of C_(3)N_(4) had a great effect on the photocatalytic performance.Moreover,the photocatalytic activities were higher in acidic media than those in alkaline conditions.The adsorption of methyl orange was enhanced,and the recombination of photogenerated electrons and holes was suppressed with a suitable content of C_(3)N_(4).However,too much loading content of C_(3)N_(4) resulted in a poor dispersion of C_(3)N_(4) as the aggregated C_(3)N_(4) can behave as recombination centers.In addition,the prepared ZnO-C_(3)N_(4) thin film can be used for the water splitting in water-methanol system under simulated solar light irradiation.展开更多
文摘Photocatalytic degradation of phenol selected as model compound of organic pollutant had been investigated in aqueous titanium dioxide （TiO2） dispersion under UV irradiation. The effects of various parameters such as pH, catalyst concentration, phenol concentration, anions, metal ions, electron acceptors, and surfactants on the photocatalytic degradation of phenol were investigated. The degradation kinetics was determined by the change in phenol concentration employing UV-Vis spectrometry as a function of irradiation time. The degradation kinetics of phenol follows pseudo first-order kinetics. The results showed a significant dependence of the photocatalytic degradation of phenol on the functional parameters. The probable promising roles of the additives on the degradation process were discussed.
基金Acknowledgements We are grateful to the National Basic Research Program of China （973 Program, No. 2007CB613303） for financial support. This work was also supported by the National Natural Science Foundation of China （No. 20873053）.
文摘Highly photocatalytically active cobalt-doped ZnO （ZnO：Co） nanorods have been prepared by a facile hydrothermal process. X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering and UV-vis diffuse reflectance spectroscopy confirmed that the dopant ions substitute for some of the lattice zinc ions, and furthermore, that Co〉 and Co〉 ions coexist. The as-prepared ZnO：Co samples have an extended light absorption range compared with pure ZnO and showed highly efficient photocatalytic activity, only requiring 60 rain to decompose -93% of alizarin red dye under visible light irradiation （λ 〉 420 nm）, The photophysical mechanism of the visible photocatalytic activity was investigated with the help of surface photovoltage spectroscopy. The results indicated that a strong electronic interaction between the Co and ZnO was present, and that the incorporation of Co promoted the charge separation and enhanced the charge transfer ability and, at the same time, effectively inhibited the recombination of photogenerated charge carriers in ZnO, resulting in high visible light photocatalytic activity.
文摘The solar-driven catalytic conversion of CO2 to useful chemical fuels is regarded as an environmentally friendly approach to reduce the consumption of fossil fuels and mitigate the greenhouse effect.However,it is highly intriguing and challenging to promote the selectivity and efficiency of visible-light-responsive photocatalysts that favor the adsorption of CO2 in photoreduction processes.In this work,three-dimensional hierarchical Cd0.8Zn0.2S flowers(C8Z2S-F)with ultrathin petals were successfully synthesized through an in-situ self-assembly growth process using sodium citrate as a morphology director.The flower-like Cd0.8Zn0.2S solid solution exhibited remarkable photocatalytic performance in the reduction of CO2,generating CO up to 41.4μmol g^−1 under visible-light illumination for 3 h;this was nearly three times greater than that of Cd0.8Zn0.2S nanoparticles(C8Z2S-NP)(14.7μmol g^−1).Particularly,a comparably high selectivity of 89.9%for the conversion of CO2 to CO,with a turnover number of 39.6,was obtained from the solar-driven C8Z2S-F system in the absence of any co-catalyst or sacrificial agent.Terahertz time-domain spectroscopy indicated that the introduction of flower structures enhanced the light-harvesting capacity of C8Z2S-F.The in situ diffuse reflectance infrared Fourier transform spectroscopy unveiled the existence of surface-adsorbed species and the conversion of photoreduction intermediates during the photocatalytic process.Empirical characterizations and predictions of the photocatalytic mechanism demonstrated that the flower-like Cd0.8Zn0.2S solid solution possessed desirable CO2 adsorption properties and an enhanced charge-transfer capability,thus providing a highly effective photocatalytic reduction of CO2.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Grant No.21406184)the Foundation of Youth Science and Technology Innovation Team of Sichuan Province(Grant No.2015TD0007).
文摘The performance of Mn-TiO2/sepiolite photocatalysts prepared by the solgel method and calcinated at different temperatures was studied in the photocatalytic degradation of direct fast emerald green dye under visible light irradiation,and a series of analytical techniques such as XRD,SEM,FTIR,TG-DSC,XPS,UV-vis-DRS and Raman spectroscopy were used to characterize the morphology,structure and optical properties of the photocatalysts.It is found that the anatase TiO2 was formed in all photocatalysts.Mn4+might incorporate into the lattice structure of TiO2 and partially replace Ti4+,thus causing the defects in the crystal structure and the broadening of the spectral response range of TiO2.At the same time,TiO2 particles were dispersed on the surface of the sepiolite,which immobilized TiO2 particles with sepiolite via the bond of Ti-O-Si.Mn-TiO2/sepiolite calcined at 400°C exhibits the highest photocatalytic activity and the degradation rate of direct fast emerald green is up to 98.13%.Meanwhile,it also shows good stability and universality.
基金financially supported by the National Natural Science Foundation of China(No.51574071)。
文摘Nanoflower-like ZnO-C_(3)N_(4) thin film with a porous net structure was successfully synthesized by a simple chemical corrosion method.The prepared ZnOC_(3)N_(4) thin films presented remarkable photocatalytic activities for the degradation of methyl orange under visible light irradiation,and more than 90%methyl orange was removed from water by ZnO-C_(3)N_(4) composite.Meanwhile,the ZnO-C_(3)N_(4) composite presented an enhanced photocatalytic stability.The loading content of C_(3)N_(4) had a great effect on the photocatalytic performance.Moreover,the photocatalytic activities were higher in acidic media than those in alkaline conditions.The adsorption of methyl orange was enhanced,and the recombination of photogenerated electrons and holes was suppressed with a suitable content of C_(3)N_(4).However,too much loading content of C_(3)N_(4) resulted in a poor dispersion of C_(3)N_(4) as the aggregated C_(3)N_(4) can behave as recombination centers.In addition,the prepared ZnO-C_(3)N_(4) thin film can be used for the water splitting in water-methanol system under simulated solar light irradiation.
