Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted ure...Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfactants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The optical absorption of Zn O extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity; this was mainly attributed to the extended photoresponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.展开更多
S-doped TiO2(S-TiO2) films were immobilized on flexible low-cost aluminum sheets(S-TiO2-AS) using a sol-gel dipping process and low post-processing temperatures. The photocatalytic degradation of toxic organic vapors ...S-doped TiO2(S-TiO2) films were immobilized on flexible low-cost aluminum sheets(S-TiO2-AS) using a sol-gel dipping process and low post-processing temperatures. The photocatalytic degradation of toxic organic vapors using the prepared films was evaluated using a continuous-flow glass tube under visible light exposure. The surface properties of the S-TiO2-AS and TiO2-AS films were examined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and ultraviolet-visible spectroscopy. The photolysis of benzene, toluene, ethyl benzene, and xylene(BTEX) did not occur on the bare AS. In contrast, the photocatalytic degradation efficiencies of the target pollutants using S-TiO2-AS were higher than those obtained using reference TiO2-AS photocatalyst. In particular, the average photocatalytic degradation efficiencies of BTEX using S-TiO2-0.8-AS(S/Ti ratio = 0.8) over a 3-h process were 34%, 78%, 91%, and 94%, respectively, whereas those of TiO2-AS were 2%, 11%, 21%, and 36%, respectively. The photocatalytic decompo-sition efficiencies of BTEX under visible irradiation using S-TiO2-AS increased with increasing S/Ti ratios from 0.2 to 0.8, but decreased when the ratio further increased to 1.6. Thus, S-TiO2-AS can be prepared using optimal S/Ti ratios. The degradation of BTEX over S-TiO2-AS depended on the air flow rates and initial concentrations of the target chemical. Overall, under optimal conditions, S-TiO2-AS can be effectively applied for the purification of toxic organic vapors.展开更多
A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated...A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated using X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Solid UV reflectance spectra testing found that CdS/Fe_(3)O_(4)nanocomposites had good light absorption throughout the spectral range,promoting their photocatalytic properties.Under visible light irradiation,CdS/Fe_(3)O_(4)(2∶5)with a mass ratio of 2∶5 exhibited excellent photocatalytic perfor-mance,with a degradation rate of 98.8%for rhodamine B.Furthermore,after five cycles of photocatalytic degrada-tion reaction,the rhodamine B degradation rate remained at 96.2%,indicating that the photocatalysts have good pho-tocatalytic stability.展开更多
ZnO/ZnGa_2O_4 composite microspheres with heterojunction were successfully synthesized by one-pot hydrothermal method.These samples were characterized by TG/DTA,XRD,TEM,HRTEM,UV-vis DRS,FL and BET techniques.The resul...ZnO/ZnGa_2O_4 composite microspheres with heterojunction were successfully synthesized by one-pot hydrothermal method.These samples were characterized by TG/DTA,XRD,TEM,HRTEM,UV-vis DRS,FL and BET techniques.The results indicated the as-prepared samples showed better degree of crystalline and large specific surface area.The photocatalytic activity was evaluated by degradation of methyl orange with the concentration of 50 mg/L under the irradiation of simulated sunlight.The effects of molar ratio of Zn to Ga and calcination temperature on the photocatalytic activity were investigated in detail.The results showed that the highest photocatalytic degradation efficiency was observed at the molar ratio of Zn to Ga of 1:0.5 in the starting materials and the calcination temperature of 400 °C.The maximum photocatalytic degradation rate of MO was 97.1% within 60 min under the simulated sunlight irradiation,which is greatly higher than that of ZnO and ZnGa_2O_4.展开更多
The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a sili...The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.展开更多
A slightly modified method for 10-ethyl flavin was developed in the present study. The synthetic product was characterized by nuclear magnetic resonance(NMR) and mass spectrometry, and used to catalyze the photocataly...A slightly modified method for 10-ethyl flavin was developed in the present study. The synthetic product was characterized by nuclear magnetic resonance(NMR) and mass spectrometry, and used to catalyze the photocatalytic degradation of phenol, 2, 4-dichlorophenoxyacetic acid, p-nitrophenol, 4-chlorophenol, 4-methoxyphenol, 4-chloro-2-methyl-phenoxyacetic acid and2, 4, 5-trichloro-phenoxyacetic acid. Both HPLC(high performance liquid chromatography) and GC-MS data suggested that all phenols were degraded in the presence of either flavin at micromolar concentrations under direct sun light. A rapid breakdown of the phenols was observed. The degradation efficiency was clearly dependent on phenol type. In a decreasing order of degradation efficiency over a 2-h period, the phenols were 4-chlorophenol and 4-methoxyphenol(-80%) > phenoxyacetic acids(60%-65%) > nitrophenol and phenol(-35%).展开更多
The highly ordered and vertically oriented pure TiO2 nanotube arrays(TONTAs) are synthesized by anodic oxidation of titanium foils in fluoride-based electrolytes under different temperatures and voltages. Then TONTAs ...The highly ordered and vertically oriented pure TiO2 nanotube arrays(TONTAs) are synthesized by anodic oxidation of titanium foils in fluoride-based electrolytes under different temperatures and voltages. Then TONTAs are treated at different temperatures. X-ray diffraction(XRD) patterns show that its structure is anatase at 500 with the ℃ temperature increasing to 700 ℃, the most of anatase will transform to rutile, the nanotube arrays form granular titanium oxide, while at 900 ℃, anatase will transform to rutile completely. The experimental results of photocatalytic degradation of methylene blue solution show that the cobalt-manganese co-doped TONTAs have good photocatalytic degradation efficiency.展开更多
We report layer-by-layer （LbL） assembly of TiO2 and H4SiW12O40 （SiW12） multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange （MO）. The photocatalytic efficiency of th...We report layer-by-layer （LbL） assembly of TiO2 and H4SiW12O40 （SiW12） multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange （MO）. The photocatalytic efficiency of the obtained multilayer film increases along with the decrease of pH and salt concentration of the incubation solution. The results show that MO can be almost re- moved in pH 2.0 solution without salt addition in the first 60 min incubation when MO concentration is lower than 15 mg/L. Different salts show an apparent inhibitory effect on photocatalytic degradation of MO with the order of ZnC12〉KCI〉 NaC1〉LiCI. The TiO2/SiW12 multilayer film maintains photocatalytic activity even after five degradation cycles. The reaction of MO photodegradation accords with an apparent first-order dynamics.展开更多
文摘Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfactants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The optical absorption of Zn O extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity; this was mainly attributed to the extended photoresponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.
基金supported by the National Research Foundation of Korea Grant Funded by the Korean Government (2011-0027916)
文摘S-doped TiO2(S-TiO2) films were immobilized on flexible low-cost aluminum sheets(S-TiO2-AS) using a sol-gel dipping process and low post-processing temperatures. The photocatalytic degradation of toxic organic vapors using the prepared films was evaluated using a continuous-flow glass tube under visible light exposure. The surface properties of the S-TiO2-AS and TiO2-AS films were examined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and ultraviolet-visible spectroscopy. The photolysis of benzene, toluene, ethyl benzene, and xylene(BTEX) did not occur on the bare AS. In contrast, the photocatalytic degradation efficiencies of the target pollutants using S-TiO2-AS were higher than those obtained using reference TiO2-AS photocatalyst. In particular, the average photocatalytic degradation efficiencies of BTEX using S-TiO2-0.8-AS(S/Ti ratio = 0.8) over a 3-h process were 34%, 78%, 91%, and 94%, respectively, whereas those of TiO2-AS were 2%, 11%, 21%, and 36%, respectively. The photocatalytic decompo-sition efficiencies of BTEX under visible irradiation using S-TiO2-AS increased with increasing S/Ti ratios from 0.2 to 0.8, but decreased when the ratio further increased to 1.6. Thus, S-TiO2-AS can be prepared using optimal S/Ti ratios. The degradation of BTEX over S-TiO2-AS depended on the air flow rates and initial concentrations of the target chemical. Overall, under optimal conditions, S-TiO2-AS can be effectively applied for the purification of toxic organic vapors.
文摘A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated using X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Solid UV reflectance spectra testing found that CdS/Fe_(3)O_(4)nanocomposites had good light absorption throughout the spectral range,promoting their photocatalytic properties.Under visible light irradiation,CdS/Fe_(3)O_(4)(2∶5)with a mass ratio of 2∶5 exhibited excellent photocatalytic perfor-mance,with a degradation rate of 98.8%for rhodamine B.Furthermore,after five cycles of photocatalytic degrada-tion reaction,the rhodamine B degradation rate remained at 96.2%,indicating that the photocatalysts have good pho-tocatalytic stability.
基金Projects(21306041,21271071)supported by the National Natural Science Foundation of ChinaProject(15A076)supported by the Scientific Research Foundation of Hunan Provincial Education Department of China
文摘ZnO/ZnGa_2O_4 composite microspheres with heterojunction were successfully synthesized by one-pot hydrothermal method.These samples were characterized by TG/DTA,XRD,TEM,HRTEM,UV-vis DRS,FL and BET techniques.The results indicated the as-prepared samples showed better degree of crystalline and large specific surface area.The photocatalytic activity was evaluated by degradation of methyl orange with the concentration of 50 mg/L under the irradiation of simulated sunlight.The effects of molar ratio of Zn to Ga and calcination temperature on the photocatalytic activity were investigated in detail.The results showed that the highest photocatalytic degradation efficiency was observed at the molar ratio of Zn to Ga of 1:0.5 in the starting materials and the calcination temperature of 400 °C.The maximum photocatalytic degradation rate of MO was 97.1% within 60 min under the simulated sunlight irradiation,which is greatly higher than that of ZnO and ZnGa_2O_4.
文摘The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.
文摘A slightly modified method for 10-ethyl flavin was developed in the present study. The synthetic product was characterized by nuclear magnetic resonance(NMR) and mass spectrometry, and used to catalyze the photocatalytic degradation of phenol, 2, 4-dichlorophenoxyacetic acid, p-nitrophenol, 4-chlorophenol, 4-methoxyphenol, 4-chloro-2-methyl-phenoxyacetic acid and2, 4, 5-trichloro-phenoxyacetic acid. Both HPLC(high performance liquid chromatography) and GC-MS data suggested that all phenols were degraded in the presence of either flavin at micromolar concentrations under direct sun light. A rapid breakdown of the phenols was observed. The degradation efficiency was clearly dependent on phenol type. In a decreasing order of degradation efficiency over a 2-h period, the phenols were 4-chlorophenol and 4-methoxyphenol(-80%) > phenoxyacetic acids(60%-65%) > nitrophenol and phenol(-35%).
基金supported by the National Natural Science Foundation of China(No.11105117)Province Natural Science Foundation of Shandong(No.Y2004A11)Yantai University Postdoctoral Foundation(No.WL03B15)
文摘The highly ordered and vertically oriented pure TiO2 nanotube arrays(TONTAs) are synthesized by anodic oxidation of titanium foils in fluoride-based electrolytes under different temperatures and voltages. Then TONTAs are treated at different temperatures. X-ray diffraction(XRD) patterns show that its structure is anatase at 500 with the ℃ temperature increasing to 700 ℃, the most of anatase will transform to rutile, the nanotube arrays form granular titanium oxide, while at 900 ℃, anatase will transform to rutile completely. The experimental results of photocatalytic degradation of methylene blue solution show that the cobalt-manganese co-doped TONTAs have good photocatalytic degradation efficiency.
基金financially supported by the National Natural Science Foundation of China (21033005)the National Basic Research Program of China (973 Program, 2009CB930103)Natural Science Foundation of Shandong Province (2009ZRB01876)
文摘We report layer-by-layer （LbL） assembly of TiO2 and H4SiW12O40 （SiW12） multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange （MO）. The photocatalytic efficiency of the obtained multilayer film increases along with the decrease of pH and salt concentration of the incubation solution. The results show that MO can be almost re- moved in pH 2.0 solution without salt addition in the first 60 min incubation when MO concentration is lower than 15 mg/L. Different salts show an apparent inhibitory effect on photocatalytic degradation of MO with the order of ZnC12〉KCI〉 NaC1〉LiCI. The TiO2/SiW12 multilayer film maintains photocatalytic activity even after five degradation cycles. The reaction of MO photodegradation accords with an apparent first-order dynamics.
