Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microsc...Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscopy） and ultraviolet-visible spectroscopy. The XRD results showed that the FWHM of Sn-doped ZnO film increased due to the substitution of Sn for Zn, the tin doping within the film causes the ZnO crystallinity to deteriorate. The grains of the film doped with Sn using dibutyltin diacetate were found to be non-uniform distribution through the sample but those appeared to form ganglia-like hills in the case of pure ZnO film. Furthermore, the Sn-doped ZnO films were tested with respect to the photocatalysis in aqueous solutions of MG （malachite green） upon UV-light illumination and in darkness. It was found that Sn-doped ZnO films prepared under specific conditions showed a lower photocatalytic activity than that of pure ZnO films.展开更多
Zinc oxide(ZnO) nanoparticles of varying sizes(20, 44 and 73 nm) have been successfully synthesized by a hybrid electrochemical-thermal method using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and ...Zinc oxide(ZnO) nanoparticles of varying sizes(20, 44 and 73 nm) have been successfully synthesized by a hybrid electrochemical-thermal method using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and cathode in an undivided cell under galvanostatic mode at room temperature. The as-synthesized product was characterized by X-ray diffraction(XRD), X-ray photoelectron spectra(XPS), Scanning electron microscopy along with Energy dispersive analysis of X-ray(SEM/EDAX), Transmission electron microscopy(TEM), Ultra Violet- Diffuse reflectance spectroscopic methods(UV-DRS). and UV-DRS spectral methods.The as-synthesized compound were single-crystalline and Rietveld refinement of calcined samples exhibited hexagonal(Wurtzite) structure with space group of P63mc(No.186). The band gaps for synthesized ZnO nanoparticles were 3.07, 3.12 and 3.13 e V, respectively, based on the results of diffuse reflectance spectra(DRS). The electrochemically synthesized ZnO powder was used as photocatalysts for UV-induced degradation of Methylene blue(MB). Photodegradation was also found to be function of exposure time and dye solution p H. It has been found that as-synthesized powder has excellent photocatalytic activity with 92% degradation of MB, indicating ZnO nanoparticles can play an important role as a semiconductor photocatalyst.展开更多
Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with...Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Zinc oxide was set with 0.1 mol/L of phosphoric acid at P/Zn = 1/1 and 1/2, and then shaking in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The P/Zn ratio in preparation had an effect on the reaction between phosphoric acid and zinc oxide. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.展开更多
In order to clarify the impact of activated carbon and anion exchange resin on photocatalytic oxidation (PCO) of textile industry wastewater, TiO2-based PCO was investigated with aqueous solutions containing the react...In order to clarify the impact of activated carbon and anion exchange resin on photocatalytic oxidation (PCO) of textile industry wastewater, TiO2-based PCO was investigated with aqueous solutions containing the reactive dye Reactive Blue 4 (RB4) and with a textile dye house effluent in the absence and in the presence of powdered activated carbon (PAC) and the anion exchange resin Lewatit MP 500. Addition of Lewatit improved RB4 removal to a larger extent than PAC addition. Contrasting to chloride and sulfate, hydrogen carbonate clearly inhibited PCO of RB4. However, the depression of dye removal by hydrogen carbonate was minute in the presence of Lewatit although the hydrogen carbonate concentration was not markedly decreased. Unfortunately, the beneficial effect of Lewatit addition on PCO nearly disappeared when the Lewatit/TiO2 mixture was reused three times. This was probably caused by oxidative damage of the resin. Color removal from the real dye house effluent during PCO was improved by Lewatit, but not by PAC. Contrastingly, PAC addition increased TOC removal by PCO from the real wastewater to some extent, while Lewatit had no impact. Sorbent addition does not lead to an acceptable area demand for solar PCO of the dye house effluent.展开更多
ITO/CdS/ZnO interface composite films were successfully prepared by subsequent electrodeposition of CdS and ZnO onto indium tin oxide （ITO） glass substrates. The obtained ITO/CdS/ZnO composite films were characteriz...ITO/CdS/ZnO interface composite films were successfully prepared by subsequent electrodeposition of CdS and ZnO onto indium tin oxide （ITO） glass substrates. The obtained ITO/CdS/ZnO composite films were characterized with X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and UV-Vis spectroscopy. The photocatalytic activity of ITO/CdS/ZnO composite films were investigated using methyl orange （MO） as a model organic compound under UV light irradiation. The influence of operating parameters on MO degradation including initial concentration of MO, pH value of solution, and inorganic anion species over the composite films were examined. A blue shift of absorption threshold was observed for the ITO/CdS/ZnO film in comparison with ITO/ZnO film. ITO/CdS/ZnO composite films prepared under specific conditions showed a higher photocatalytic activity than that of ITO/ZnO films. It was also found that the photocatalytic degradation of MO on the composite films followed pseudo-first order kinetics.展开更多
We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-g...We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-gel process at low temperature. The samples were characterized by means of several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogra- vimetric analysis. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under UV-Vis illumination. Moreover, flame-retardancy was tested by vertical flame spread test. The optimum add-on value for donating flame-retardancy onto cellulosic fabric was obtained to be in the range of 15.24 to 23.20 g of the ZnO per 100 g of fabric. Thermogravimetric analysis of pure and flame-retarded samples were accomplished and discussed. The results obtained are in agreement with Wall effect theory and Coating theory. The originality of this work on introducing photoactive flame-retarded fibers is highly valuable for industrial implementation.展开更多
Rare earth elements doped with zinc oxide nanoparticles(ZnO-NPs)have gathered a remarkable interest for their potential credence due to their high luminescent intensities.In this research,europium ion(Eu^(3+))doped an...Rare earth elements doped with zinc oxide nanoparticles(ZnO-NPs)have gathered a remarkable interest for their potential credence due to their high luminescent intensities.In this research,europium ion(Eu^(3+))doped and undoped zinc oxide nanoparticles(Eu_(1-x)Zn_(x)O)(x=0.03,0.06,0.09)were synthesized via co-precipitation method.The effects of varying the concentration of the europium ion(Eu^(3+))on the structure and optical properties were investigated.The structural and optical properties of europium ion(Eu^(3+))doped and un-doped zinc oxide nanoparticles(ZnO NPs)were characterized by XRD,UV-Vis,Photoluminescence,and FT-IR Spectroscopy.The XRD results reveal the Europium ion(Eu^(3+))was successfully incorporated into the zinc oxide host matrix and made highly crystalline.All the synthesized samples have a hexagonal wurtzite structure.UV-Vis absorption spectra measurements revealed increasing the dopant concentration increases the energy band compared to the undoped zinc oxide nanoparticles.Photoluminescence spectra confirmed doping europium ion(Eu^(3+))predominantly enhances the visible emission with various series characteristics of blue and green emission compared to undoped zinc oxide nanoparticles(ZnO NPs)which exhibits the near band emission.Fourier Transform Infra Red(FTIR)spectral analysis indicated the presence of functional groups attached to Europium ion(Eu^(3+))doped and undoped zinc oxide nanoparticles(ZnO NPs).In addition,the presence of an additional spectrum band with increasing the concentration of dopant amount demonstrates that europium ions(Eu^(3+))were successfully substituted into the zinc oxide host matrix.The photocatalytic activity response is investigated using organic methylene blue(MB)as a pollutant model and dopant played the role in enhancing the photocatalytic kinetics because Eu^(3+)ions act as an electron acceptor to promote charge separation and photocatalytic activity.The photocatalytic activity of europium ion(Eu^(3+))doped zinc oxide nanoparticles has higher performance than undoped zinc oxide nanoparticles(ZnO-NPs)since the dopant has the potential candidate in minimizing the recombination probability which in turn improves the performance of photocatalytic activities which makes it suitable for the local environment.展开更多
文摘Pure ZnO and Sn-doped ZnO thin films were successfully prepared by the spray pyrolysis method onto glass substrates. The obtained films were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscopy） and ultraviolet-visible spectroscopy. The XRD results showed that the FWHM of Sn-doped ZnO film increased due to the substitution of Sn for Zn, the tin doping within the film causes the ZnO crystallinity to deteriorate. The grains of the film doped with Sn using dibutyltin diacetate were found to be non-uniform distribution through the sample but those appeared to form ganglia-like hills in the case of pure ZnO film. Furthermore, the Sn-doped ZnO films were tested with respect to the photocatalysis in aqueous solutions of MG （malachite green） upon UV-light illumination and in darkness. It was found that Sn-doped ZnO films prepared under specific conditions showed a lower photocatalytic activity than that of pure ZnO films.
基金CSIR, New-Delhi for SRF [Sanction No. 09/908(0002) 2K9-EMR-I]DST [No. S.R/S3/ME/014/2007]Government of India (GOI) for research grant
文摘Zinc oxide(ZnO) nanoparticles of varying sizes(20, 44 and 73 nm) have been successfully synthesized by a hybrid electrochemical-thermal method using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and cathode in an undivided cell under galvanostatic mode at room temperature. The as-synthesized product was characterized by X-ray diffraction(XRD), X-ray photoelectron spectra(XPS), Scanning electron microscopy along with Energy dispersive analysis of X-ray(SEM/EDAX), Transmission electron microscopy(TEM), Ultra Violet- Diffuse reflectance spectroscopic methods(UV-DRS). and UV-DRS spectral methods.The as-synthesized compound were single-crystalline and Rietveld refinement of calcined samples exhibited hexagonal(Wurtzite) structure with space group of P63mc(No.186). The band gaps for synthesized ZnO nanoparticles were 3.07, 3.12 and 3.13 e V, respectively, based on the results of diffuse reflectance spectra(DRS). The electrochemically synthesized ZnO powder was used as photocatalysts for UV-induced degradation of Methylene blue(MB). Photodegradation was also found to be function of exposure time and dye solution p H. It has been found that as-synthesized powder has excellent photocatalytic activity with 92% degradation of MB, indicating ZnO nanoparticles can play an important role as a semiconductor photocatalyst.
文摘Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Zinc oxide was set with 0.1 mol/L of phosphoric acid at P/Zn = 1/1 and 1/2, and then shaking in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The P/Zn ratio in preparation had an effect on the reaction between phosphoric acid and zinc oxide. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.
文摘In order to clarify the impact of activated carbon and anion exchange resin on photocatalytic oxidation (PCO) of textile industry wastewater, TiO2-based PCO was investigated with aqueous solutions containing the reactive dye Reactive Blue 4 (RB4) and with a textile dye house effluent in the absence and in the presence of powdered activated carbon (PAC) and the anion exchange resin Lewatit MP 500. Addition of Lewatit improved RB4 removal to a larger extent than PAC addition. Contrasting to chloride and sulfate, hydrogen carbonate clearly inhibited PCO of RB4. However, the depression of dye removal by hydrogen carbonate was minute in the presence of Lewatit although the hydrogen carbonate concentration was not markedly decreased. Unfortunately, the beneficial effect of Lewatit addition on PCO nearly disappeared when the Lewatit/TiO2 mixture was reused three times. This was probably caused by oxidative damage of the resin. Color removal from the real dye house effluent during PCO was improved by Lewatit, but not by PAC. Contrastingly, PAC addition increased TOC removal by PCO from the real wastewater to some extent, while Lewatit had no impact. Sorbent addition does not lead to an acceptable area demand for solar PCO of the dye house effluent.
文摘ITO/CdS/ZnO interface composite films were successfully prepared by subsequent electrodeposition of CdS and ZnO onto indium tin oxide （ITO） glass substrates. The obtained ITO/CdS/ZnO composite films were characterized with X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and UV-Vis spectroscopy. The photocatalytic activity of ITO/CdS/ZnO composite films were investigated using methyl orange （MO） as a model organic compound under UV light irradiation. The influence of operating parameters on MO degradation including initial concentration of MO, pH value of solution, and inorganic anion species over the composite films were examined. A blue shift of absorption threshold was observed for the ITO/CdS/ZnO film in comparison with ITO/ZnO film. ITO/CdS/ZnO composite films prepared under specific conditions showed a higher photocatalytic activity than that of ITO/ZnO films. It was also found that the photocatalytic degradation of MO on the composite films followed pseudo-first order kinetics.
文摘We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-gel process at low temperature. The samples were characterized by means of several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogra- vimetric analysis. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under UV-Vis illumination. Moreover, flame-retardancy was tested by vertical flame spread test. The optimum add-on value for donating flame-retardancy onto cellulosic fabric was obtained to be in the range of 15.24 to 23.20 g of the ZnO per 100 g of fabric. Thermogravimetric analysis of pure and flame-retarded samples were accomplished and discussed. The results obtained are in agreement with Wall effect theory and Coating theory. The originality of this work on introducing photoactive flame-retarded fibers is highly valuable for industrial implementation.
基金financially supported by Adama Science and Technology University and the Ministry of Innovation and Technology of Ethiopia.
文摘Rare earth elements doped with zinc oxide nanoparticles(ZnO-NPs)have gathered a remarkable interest for their potential credence due to their high luminescent intensities.In this research,europium ion(Eu^(3+))doped and undoped zinc oxide nanoparticles(Eu_(1-x)Zn_(x)O)(x=0.03,0.06,0.09)were synthesized via co-precipitation method.The effects of varying the concentration of the europium ion(Eu^(3+))on the structure and optical properties were investigated.The structural and optical properties of europium ion(Eu^(3+))doped and un-doped zinc oxide nanoparticles(ZnO NPs)were characterized by XRD,UV-Vis,Photoluminescence,and FT-IR Spectroscopy.The XRD results reveal the Europium ion(Eu^(3+))was successfully incorporated into the zinc oxide host matrix and made highly crystalline.All the synthesized samples have a hexagonal wurtzite structure.UV-Vis absorption spectra measurements revealed increasing the dopant concentration increases the energy band compared to the undoped zinc oxide nanoparticles.Photoluminescence spectra confirmed doping europium ion(Eu^(3+))predominantly enhances the visible emission with various series characteristics of blue and green emission compared to undoped zinc oxide nanoparticles(ZnO NPs)which exhibits the near band emission.Fourier Transform Infra Red(FTIR)spectral analysis indicated the presence of functional groups attached to Europium ion(Eu^(3+))doped and undoped zinc oxide nanoparticles(ZnO NPs).In addition,the presence of an additional spectrum band with increasing the concentration of dopant amount demonstrates that europium ions(Eu^(3+))were successfully substituted into the zinc oxide host matrix.The photocatalytic activity response is investigated using organic methylene blue(MB)as a pollutant model and dopant played the role in enhancing the photocatalytic kinetics because Eu^(3+)ions act as an electron acceptor to promote charge separation and photocatalytic activity.The photocatalytic activity of europium ion(Eu^(3+))doped zinc oxide nanoparticles has higher performance than undoped zinc oxide nanoparticles(ZnO-NPs)since the dopant has the potential candidate in minimizing the recombination probability which in turn improves the performance of photocatalytic activities which makes it suitable for the local environment.
