β-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and linear sweep voltammetry.We confirmed pure β-PbO2 crysta...β-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and linear sweep voltammetry.We confirmed pure β-PbO2 crystals were on the electrode and it had a high oxygen evolution potential.The photoactivity and photoelectrochemical（PEC） properties of the β-PbO2 electrode were investigated under visible light irradiation（λ 〉 420 nm） for the decolorization of Methylene Blue.Pseudo first-order kinetics parameter（Kapp） for dye decolorization using the β-PbO2 electrode achieved 6.71×10-4 min-1 under visible light irradiation,which indicated its excellent visible light-induced photoactivity.The Kapp of the PEC process was as much as 1.41×10-3 min-1 and was 1.71 times that of visible light irradiation or electrolysis even in the presence of the β-PbO2 electrode.A significant synergetic effect was observed in the PEC system.We also employed TiO2 modified β-PbO2 electrodes in this test,which revealed that the TiO2 immobilized on the β-PbO2 electrode inhibited the visible light-induced PEC efficiency despite the amount of TiO2 used for electrode preparation.The β-PbO2 electrode was also superior to the dimensionally stable anode（Ti/Ru0.3Ti0.7O2） in visible light-induced photoactivity and PEC efficiency.展开更多
Hydroxyl radicals play the key role during electrochemical oxidation and photoelectrochemical oxidation. The production and effect of hydroxyl radicals on the interface between DSA anode and water was investigated by ...Hydroxyl radicals play the key role during electrochemical oxidation and photoelectrochemical oxidation. The production and effect of hydroxyl radicals on the interface between DSA anode and water was investigated by examining the quenching effect of iso-propanol on Orange II decolorization. We observed that with an increase in electrode potential from 4 to 12 V across electrodes at pH 7.0, the contribution percentage of hydroxyl radicals increased dramatically. More OH radicals were produced in acidic and alkaline conditions than at neutral conditions. At electrode potential of 4 V, the contribution percentage of hydroxyl radicals was obviously higher at near neutral pH conditions, while removal efficiency of Orange/I achieved was the lowest concurrently. Finally, for photocatalytic oxidation, electrochemical oxidation, and photoelectrochemical oxidation using the same DSA electrode, the effect of hydroxyl radicals proved to be dominant in photocatalytic oxidation but the contribution of hydroxyl radicals was not dominant in electrochemical oxidation, which implies the necessity of UV irradiation for electrochemical oxidation during water treatment.展开更多
The effect of ultraviolet irradiation on generation of radicals and formation of intermediates was investigated in electrochemical oxidation of the azo-dye Orange I1 using a TiO2-modified β- PbO2 electrode. It was fo...The effect of ultraviolet irradiation on generation of radicals and formation of intermediates was investigated in electrochemical oxidation of the azo-dye Orange I1 using a TiO2-modified β- PbO2 electrode. It was found that a characteristic absorbance of quinonic compounds at 255 nm, which is responsible for the rate-determining step during aromatics degradation, was formed only in electrocatalytic oxidation. The dye can be oxidized by either HO radicals or direct electron transfer. Quinonic compounds were produced concurrently. The removal of TOC by photo-assisted electrocatalytic oxidation was 1.56 times that of the sum of the other two processes, indicating a significant synergetic effect. In addition, once the ultraviolet irradiation was introduced into the process of electrocatalytic oxidation, the degradation rate of quinonic compounds was enhanced by as much as a factor of two. The more efficient generation of HO radicals resulted from the introduction of ultraviolet irradiation in electrocatalytic oxidation led to the significant synergetic effect as well as the inhibiting effect on the accumulation of quinonic compounds.展开更多
With the improvement of people’s living standards,a large number of petroleum products,daily necessities and decorations that can produce volatile organic compounds are used in decoration,which seriously affects the ...With the improvement of people’s living standards,a large number of petroleum products,daily necessities and decorations that can produce volatile organic compounds are used in decoration,which seriously affects the indoor air quality.Interior decoration materials have become a research hotspot in recent years.The purpose of this paper is to develop a kind of interior wall material with good indoor formaldehyde removal effect,easily using,and low cost.In this paper,combining different heat treatment temperatures of the glaze layer,tourmaline/diatomite-based interior wall tiles were prepared by ultrafine grinding,solid sintering,and low temperature calcination.The glaze layer under different heat treatment temperatures was characterized by thermogravimetric-differential thermal analysis,X-ray diffraction,and scanning electron microscope.The influences of heat treatment temperature on the microscopic morphology and structure of the glaze layer were analyzed.Taking formaldehyde as the target degradation product,the effects of tourmaline/diatomite-based interior wall tiles on the removal of formaldehyde under different heat treatment temperatures of the glaze layer were investigated.The results showed that with the increase in heat treatment temperature,the original pores of diatomite decreased,the specific surface area decreased,and the structure of tourmaline changed.At 850℃,the surface structure of the material was slightly damaged,the strength was increased,and the removal effect of formaldehyde was better.In a 1 m^(3) environmental chamber,the formaldehyde removal rate reached 73.6%in 300 min.When the temperature was increased to 950℃ and above,diatomite and the structure of tourmaline were destroyed,and the ability of the material to adsorb and degrade formaldehyde decreased.展开更多
基金supported by a GRF grant (No.CUHK477610) of the Research Grants Council of Hong Kong SAR Governmentthe National Natural Science Foundation of China (No. 50708037)
文摘β-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and linear sweep voltammetry.We confirmed pure β-PbO2 crystals were on the electrode and it had a high oxygen evolution potential.The photoactivity and photoelectrochemical（PEC） properties of the β-PbO2 electrode were investigated under visible light irradiation（λ 〉 420 nm） for the decolorization of Methylene Blue.Pseudo first-order kinetics parameter（Kapp） for dye decolorization using the β-PbO2 electrode achieved 6.71×10-4 min-1 under visible light irradiation,which indicated its excellent visible light-induced photoactivity.The Kapp of the PEC process was as much as 1.41×10-3 min-1 and was 1.71 times that of visible light irradiation or electrolysis even in the presence of the β-PbO2 electrode.A significant synergetic effect was observed in the PEC system.We also employed TiO2 modified β-PbO2 electrodes in this test,which revealed that the TiO2 immobilized on the β-PbO2 electrode inhibited the visible light-induced PEC efficiency despite the amount of TiO2 used for electrode preparation.The β-PbO2 electrode was also superior to the dimensionally stable anode（Ti/Ru0.3Ti0.7O2） in visible light-induced photoactivity and PEC efficiency.
基金supported by the National Natural Science Foundation of China (No. 50708037)the Starting Fund for Talents of North China University of Water Conservancy and Electric Power
文摘Hydroxyl radicals play the key role during electrochemical oxidation and photoelectrochemical oxidation. The production and effect of hydroxyl radicals on the interface between DSA anode and water was investigated by examining the quenching effect of iso-propanol on Orange II decolorization. We observed that with an increase in electrode potential from 4 to 12 V across electrodes at pH 7.0, the contribution percentage of hydroxyl radicals increased dramatically. More OH radicals were produced in acidic and alkaline conditions than at neutral conditions. At electrode potential of 4 V, the contribution percentage of hydroxyl radicals was obviously higher at near neutral pH conditions, while removal efficiency of Orange/I achieved was the lowest concurrently. Finally, for photocatalytic oxidation, electrochemical oxidation, and photoelectrochemical oxidation using the same DSA electrode, the effect of hydroxyl radicals proved to be dominant in photocatalytic oxidation but the contribution of hydroxyl radicals was not dominant in electrochemical oxidation, which implies the necessity of UV irradiation for electrochemical oxidation during water treatment.
基金supported by the starting fund for talents of North China University of Water Resources and Electric Power,and partially by the National Science Foundation of China(No.51378205)
文摘The effect of ultraviolet irradiation on generation of radicals and formation of intermediates was investigated in electrochemical oxidation of the azo-dye Orange I1 using a TiO2-modified β- PbO2 electrode. It was found that a characteristic absorbance of quinonic compounds at 255 nm, which is responsible for the rate-determining step during aromatics degradation, was formed only in electrocatalytic oxidation. The dye can be oxidized by either HO radicals or direct electron transfer. Quinonic compounds were produced concurrently. The removal of TOC by photo-assisted electrocatalytic oxidation was 1.56 times that of the sum of the other two processes, indicating a significant synergetic effect. In addition, once the ultraviolet irradiation was introduced into the process of electrocatalytic oxidation, the degradation rate of quinonic compounds was enhanced by as much as a factor of two. The more efficient generation of HO radicals resulted from the introduction of ultraviolet irradiation in electrocatalytic oxidation led to the significant synergetic effect as well as the inhibiting effect on the accumulation of quinonic compounds.
基金financially supported by the Natural Science Foundation of China (No. 50708037)the National Science Fund for Excellent Young Scholars of China (No. 51522402)
文摘With the improvement of people’s living standards,a large number of petroleum products,daily necessities and decorations that can produce volatile organic compounds are used in decoration,which seriously affects the indoor air quality.Interior decoration materials have become a research hotspot in recent years.The purpose of this paper is to develop a kind of interior wall material with good indoor formaldehyde removal effect,easily using,and low cost.In this paper,combining different heat treatment temperatures of the glaze layer,tourmaline/diatomite-based interior wall tiles were prepared by ultrafine grinding,solid sintering,and low temperature calcination.The glaze layer under different heat treatment temperatures was characterized by thermogravimetric-differential thermal analysis,X-ray diffraction,and scanning electron microscope.The influences of heat treatment temperature on the microscopic morphology and structure of the glaze layer were analyzed.Taking formaldehyde as the target degradation product,the effects of tourmaline/diatomite-based interior wall tiles on the removal of formaldehyde under different heat treatment temperatures of the glaze layer were investigated.The results showed that with the increase in heat treatment temperature,the original pores of diatomite decreased,the specific surface area decreased,and the structure of tourmaline changed.At 850℃,the surface structure of the material was slightly damaged,the strength was increased,and the removal effect of formaldehyde was better.In a 1 m^(3) environmental chamber,the formaldehyde removal rate reached 73.6%in 300 min.When the temperature was increased to 950℃ and above,diatomite and the structure of tourmaline were destroyed,and the ability of the material to adsorb and degrade formaldehyde decreased.
