A novel method to fabricate composition- （IO） films using a positive sacrificial ZnO and topology-controlled ZnO/TiO2 inverse opals IO template has been developed. This method includes a two-step process, preparatio...A novel method to fabricate composition- （IO） films using a positive sacrificial ZnO and topology-controlled ZnO/TiO2 inverse opals IO template has been developed. This method includes a two-step process, preparation of ZnO IO by a simple electrochemical deposition using a self-assembly polystyrene colloidal crystal template and preparation of ZnO/TiO2 IO by a liquid phase deposition （LPD） process at room temperature. The composition and topology of ZnO/TiO2 IO can be easily controlled by changing the duration of the LPD. After 20 min LPD process, a ZnO/TiO2 composite IO with non-close-packed face-centered cubic air sphere array was obtained. Prolonging the duration to 60 min, a pure TiO2 IO （TIO-LPD60） with obviously thickened walls was formed. The formation mechanism for the compositional and topological variation was discussed. A preliminary study on UV photocatalytic property of the samples for degradation of methylene blue reveals that the composition and topology significantly influenced the photocatalytic activity of the IO film. The ZnO/TiO2 composite IO demonstrates a higher degree of activity than both pure ZnO and pure TiO2 IO, although they have a similar IO wall thickness. Moreover, with increasing IO wall thickness from -52 nm to -90 nm, TIO-LPD60 exhibits the highest level of photocatalytic performance.展开更多
A simple and easily operated technique was developed to fabricate GaN films. GaN films possessing hexagonal wurtzite structure were fabricated on Si(111) substrates with ZnO buffer layers through nitriding Ga2O3 films...A simple and easily operated technique was developed to fabricate GaN films. GaN films possessing hexagonal wurtzite structure were fabricated on Si(111) substrates with ZnO buffer layers through nitriding Ga2O3 films in the tube quartz furnace. ZnO buffer layers and Ga3O3 films were deposited on Si substrates in turn by using radio frequency magnetron sputtering system before the nitriding process. The structure and composition of GaN films were studied by X-ray diffraction, selected area electron diffraction and Fourier transform infrared spectrophotometer. The morphologies of GaN films were studied by scanning electron microscopy. The results show that ZnO buffer layer improves the crystalline quality and the surface morphology of the films relative to the films grown directly on silicon substrates. The measurement result of room-temperature photoluminescence spectrum indicates that the photoluminescence peaks locate at 365 nm and 422 nm.展开更多
Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film w...Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt%NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.展开更多
P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy...P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.展开更多
ZnO thin films were deposited on the substrates of （100） γ-LiAlO2 at 400,550 and 700℃ using pulsed laser deposition （PLD） with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is ...ZnO thin films were deposited on the substrates of （100） γ-LiAlO2 at 400,550 and 700℃ using pulsed laser deposition （PLD） with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400℃, the grain size of the film is less than 1μm observed by Leitz microscope and measured by X-ray diffraction （XRD）. As the substrate temperature increases to 550℃, highly-preferred c-orientation and high-quality ZnO film can be attained.While the substrate temperature rises to 700℃, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence （PL） spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on γ-LiAl02 （LAO） exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.展开更多
Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the ...Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.展开更多
TiO2 films were deposited at room temperature by DC pulse magnetron sputtering system.The crystalline structures,morphological features and photocatalytic activity of TiO2 films were systematically investigated by X-r...TiO2 films were deposited at room temperature by DC pulse magnetron sputtering system.The crystalline structures,morphological features and photocatalytic activity of TiO2 films were systematically investigated by X-ray diffraction（XRD）,atomic force microscopy（AFM） and ultraviolet spectrophotometer,respectively.The results indicated that working pressure was the key deposition parameter in？uencing the TiO2 film phase composition at room temperature,which directly affected its photocatalytic activity.With increasing working pressure,the target self-bias decreases monotonously.Therefore,low temperature TiO2 phase（anatase） could be deposited with high working pressure.The anatase TiO2 films deposited with 1.4 Pa working pressure displayed the highest photocatalytic activity by the decomposition of Methyl Orange solution,which the degradation rate reached the maximum（35%） after irradiation by ultraviolet light for 1 h.展开更多
With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition process...With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films. Anatase, rutile or amorphous TiO2 films with various crystalline structures and different photocatalytic, optical and electrical properties can be produced by varying sputtering gases, substrate temperature, annealing process, deposition rate and the characteristics of magnetron sputtering. This may in turn affect the functions of TiO2 films in many applications. Furthermore, TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.展开更多
Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, p...Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.展开更多
Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction （XR...Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, ultraviolet- visible spectroscopy （UV-Vis） and photoluminescence spectroscopy （PL）. The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange （MO） aqueous solution under visible light irradiation. The results indicate that the Cu2O/TiO2/Pt composite films are made up of three layers which are Pt layer, anatase-TiO2 layer and Cu2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu2O/TiO2/Pt three-layer film is much higher than that of the Cu2O/TiO2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.展开更多
Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room te...Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.展开更多
Three thicknesses of TiO2 films, 174, 195, and 229 nm, were deposited onto quartz substrates by sol–gel spin coating method. The as-deposited thin films were characterized by nano-crystallite with different sizes (19...Three thicknesses of TiO2 films, 174, 195, and 229 nm, were deposited onto quartz substrates by sol–gel spin coating method. The as-deposited thin films were characterized by nano-crystallite with different sizes (19–46 nm) and relatively high porous structure. Optical constants were determined and showed the lowest refractive index of 1.66 for the as-prepared films that ever reported till now. Obtained results were discussed through current theoretical ideas.展开更多
Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also...Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively.The research results show that the Ag TiO 2 thin film is mainly composed of 20-100nm Ag and TiO 2 particles.The Ag TiO 2 thin films possess a super hydrophilic ability and higher photocatalytic activity than that of pure TiO 2 thin film.展开更多
The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the ...The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the phases.Only increasing the heat-treatment time,the average grain size has no obvious change.The mechanism of grain growth in TiO 2 thin film is probably as follows:the grain of coating will become grain core later;TiO 2 sol constantly deposited on the surface of TiO 2 grain and formed membrane with increasing of coating cycle times;TiO 2 grain in the film grow steadily.展开更多
Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results ...Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(?) and Ti(?) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.展开更多
Preparation of TiO<sub>2</sub> thin films by MOCVD method is presented in this paper. A MOCVD system has been designed and built. A wide range of processing conditions are investigated to deposit TiO<su...Preparation of TiO<sub>2</sub> thin films by MOCVD method is presented in this paper. A MOCVD system has been designed and built. A wide range of processing conditions are investigated to deposit TiO<sub>2</sub> films on Si wafers starting from metal-organic precursor tetrabutyl titanate. Activation energy of the film formation （E） is obtained to be 23.6 kJ/mol. Structure of films is pure anatase when deposit temperatures are low, rutile forms at 700℃. The films also exhibit preferred crystallographic orientations which strongly depend on deposit conditions. Refractive index increases with increasing of film thickness and decreasing of deposit temperature.展开更多
The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy (AFM). The films were prepared by dip coating process. The optical properties of the films were explained on ...The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy (AFM). The films were prepared by dip coating process. The optical properties of the films were explained on the basis of the microstructure of the films.展开更多
In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface c...In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.展开更多
TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic prop...TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic properties. This review provides a deep insight into the understanding of the metal- and nonmetal-doped TiO2 photocatalysts. This article begins with the introduction of the crystal structures of TiO2 and applications of TiO2 materials. We then reviewed the doped-TiO2 system in two categories： （1） metal-doped TiO2 photocatalysts system, and （2） nonmetal-doped TiO2 photocatalysts system. Both experimental results and theoretical analyses are elaborated in this section. In the following part, for the advantages of TiO2 thin films over particles, various preparation methods to obtain TiO2 thin films are briefly discussed. Finally, this review ends with a concise conclusion and outlook of new trends in the development of TiO2-based photocatalysts.展开更多
文摘A novel method to fabricate composition- （IO） films using a positive sacrificial ZnO and topology-controlled ZnO/TiO2 inverse opals IO template has been developed. This method includes a two-step process, preparation of ZnO IO by a simple electrochemical deposition using a self-assembly polystyrene colloidal crystal template and preparation of ZnO/TiO2 IO by a liquid phase deposition （LPD） process at room temperature. The composition and topology of ZnO/TiO2 IO can be easily controlled by changing the duration of the LPD. After 20 min LPD process, a ZnO/TiO2 composite IO with non-close-packed face-centered cubic air sphere array was obtained. Prolonging the duration to 60 min, a pure TiO2 IO （TIO-LPD60） with obviously thickened walls was formed. The formation mechanism for the compositional and topological variation was discussed. A preliminary study on UV photocatalytic property of the samples for degradation of methylene blue reveals that the composition and topology significantly influenced the photocatalytic activity of the IO film. The ZnO/TiO2 composite IO demonstrates a higher degree of activity than both pure ZnO and pure TiO2 IO, although they have a similar IO wall thickness. Moreover, with increasing IO wall thickness from -52 nm to -90 nm, TIO-LPD60 exhibits the highest level of photocatalytic performance.
基金Projects(90301002 90201025) supported by the National Natural Science Foundation of China
文摘A simple and easily operated technique was developed to fabricate GaN films. GaN films possessing hexagonal wurtzite structure were fabricated on Si(111) substrates with ZnO buffer layers through nitriding Ga2O3 films in the tube quartz furnace. ZnO buffer layers and Ga3O3 films were deposited on Si substrates in turn by using radio frequency magnetron sputtering system before the nitriding process. The structure and composition of GaN films were studied by X-ray diffraction, selected area electron diffraction and Fourier transform infrared spectrophotometer. The morphologies of GaN films were studied by scanning electron microscopy. The results show that ZnO buffer layer improves the crystalline quality and the surface morphology of the films relative to the films grown directly on silicon substrates. The measurement result of room-temperature photoluminescence spectrum indicates that the photoluminescence peaks locate at 365 nm and 422 nm.
基金This work was supported financially by the Funding from the Taishan Scholarship of Climbing Plan(No.tspd20161006)the National Natural Science Foundation of China(No.51772176)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2017RCJJ018).
文摘Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt%NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775033 and 11075038
文摘P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.
文摘ZnO thin films were deposited on the substrates of （100） γ-LiAlO2 at 400,550 and 700℃ using pulsed laser deposition （PLD） with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400℃, the grain size of the film is less than 1μm observed by Leitz microscope and measured by X-ray diffraction （XRD）. As the substrate temperature increases to 550℃, highly-preferred c-orientation and high-quality ZnO film can be attained.While the substrate temperature rises to 700℃, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence （PL） spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on γ-LiAl02 （LAO） exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.
基金Project (2010JQ6008) supported by the Natural Science Foundation of Shaanxi Province,China
文摘Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.
基金supported by the Dalian Foundation for Development of Science and Technology (No.2006A13GX029)
文摘TiO2 films were deposited at room temperature by DC pulse magnetron sputtering system.The crystalline structures,morphological features and photocatalytic activity of TiO2 films were systematically investigated by X-ray diffraction（XRD）,atomic force microscopy（AFM） and ultraviolet spectrophotometer,respectively.The results indicated that working pressure was the key deposition parameter in？uencing the TiO2 film phase composition at room temperature,which directly affected its photocatalytic activity.With increasing working pressure,the target self-bias decreases monotonously.Therefore,low temperature TiO2 phase（anatase） could be deposited with high working pressure.The anatase TiO2 films deposited with 1.4 Pa working pressure displayed the highest photocatalytic activity by the decomposition of Methyl Orange solution,which the degradation rate reached the maximum（35%） after irradiation by ultraviolet light for 1 h.
文摘With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films. Anatase, rutile or amorphous TiO2 films with various crystalline structures and different photocatalytic, optical and electrical properties can be produced by varying sputtering gases, substrate temperature, annealing process, deposition rate and the characteristics of magnetron sputtering. This may in turn affect the functions of TiO2 films in many applications. Furthermore, TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.
基金Project(cstc2011jj A50008)supported by the Natural Science Foundation of Chongqing,ChinaProject(14ZB0025)supported by Education Department of Sichuan Province,China
文摘Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.
基金financially supported by the National Natural Science Foundation of China (No.51301118)the Projects of International Cooperation in Shanxi (No.2014081002)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (No.2013108)
文摘Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, ultraviolet- visible spectroscopy （UV-Vis） and photoluminescence spectroscopy （PL）. The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange （MO） aqueous solution under visible light irradiation. The results indicate that the Cu2O/TiO2/Pt composite films are made up of three layers which are Pt layer, anatase-TiO2 layer and Cu2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu2O/TiO2/Pt three-layer film is much higher than that of the Cu2O/TiO2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.
文摘Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.
文摘Three thicknesses of TiO2 films, 174, 195, and 229 nm, were deposited onto quartz substrates by sol–gel spin coating method. The as-deposited thin films were characterized by nano-crystallite with different sizes (19–46 nm) and relatively high porous structure. Optical constants were determined and showed the lowest refractive index of 1.66 for the as-prepared films that ever reported till now. Obtained results were discussed through current theoretical ideas.
文摘Ag TiO 2 thin films were prepared on glasses.The morphology and structure of Ag TiO 2 films were investigated by XRD, SEM and FT IR.The photocatalytic and hydrophilic properties of Ag TiO 2 thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively.The research results show that the Ag TiO 2 thin film is mainly composed of 20-100nm Ag and TiO 2 particles.The Ag TiO 2 thin films possess a super hydrophilic ability and higher photocatalytic activity than that of pure TiO 2 thin film.
文摘The transparent anatase TiO 2 nanometer thin films were prepared by the sol-gel method on soda-lime glass.X-ray diffraction,thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the phases.Only increasing the heat-treatment time,the average grain size has no obvious change.The mechanism of grain growth in TiO 2 thin film is probably as follows:the grain of coating will become grain core later;TiO 2 sol constantly deposited on the surface of TiO 2 grain and formed membrane with increasing of coating cycle times;TiO 2 grain in the film grow steadily.
基金Natural Science Foundation of Hubei Province, China (No. 98J029)
文摘Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(?) and Ti(?) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.
文摘Preparation of TiO<sub>2</sub> thin films by MOCVD method is presented in this paper. A MOCVD system has been designed and built. A wide range of processing conditions are investigated to deposit TiO<sub>2</sub> films on Si wafers starting from metal-organic precursor tetrabutyl titanate. Activation energy of the film formation （E） is obtained to be 23.6 kJ/mol. Structure of films is pure anatase when deposit temperatures are low, rutile forms at 700℃. The films also exhibit preferred crystallographic orientations which strongly depend on deposit conditions. Refractive index increases with increasing of film thickness and decreasing of deposit temperature.
基金We are very grateful to the National Natural Science of Foundation of China(No.69978017,59802007)Shanghai Education Committee(No JW99-TJ-03)for their help and financial supports
文摘The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy (AFM). The films were prepared by dip coating process. The optical properties of the films were explained on the basis of the microstructure of the films.
基金This work was supported by the National Natural Science Foundation of China(No.50081001)the Education Department Project of Liaoning Province(No.202073425).
文摘In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.
文摘TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic properties. This review provides a deep insight into the understanding of the metal- and nonmetal-doped TiO2 photocatalysts. This article begins with the introduction of the crystal structures of TiO2 and applications of TiO2 materials. We then reviewed the doped-TiO2 system in two categories： （1） metal-doped TiO2 photocatalysts system, and （2） nonmetal-doped TiO2 photocatalysts system. Both experimental results and theoretical analyses are elaborated in this section. In the following part, for the advantages of TiO2 thin films over particles, various preparation methods to obtain TiO2 thin films are briefly discussed. Finally, this review ends with a concise conclusion and outlook of new trends in the development of TiO2-based photocatalysts.
