Fe^(3+)-Doped Anatase TiO_2 Study Prepared by New Sol-Gel Precursors

FeTi_1-O_2（= 0.00,0.05,0.10） nanocomposites are synthesized using a sol-gel method involving an ethanol solvent in the presence of ethylene glycol as the stabilizer,and acetic acid as the chemical reagent.Their structural and optical analyses are studied to reveal their physicochemical properties.Using the x-ray diffractometer（XRD）analysis,the size of the nanoparticles（NPs） is found to be 18-32 nm,where the size of the NPs decreases down to 18 nm when Fe impurity of up to 10% is added,whereas their structure remains unchanged.The results also indicate that the structure of the NPs is tetragonal in the anatase phase.The Fourier transform infrared spectroscopy analysis suggests the presence of a vibration bond（Ti-O） in the sample.The photoluminescence analysis indicates that the diffusion of Fe^（3＋） ions into the TiO_2 matrix results in a decreasing electron-hole recombination,and increases the photocatalytic properties,where the best efficiency appears at an impurity of10%.The UV-diffuse reflection spectroscopy analysis indicates that with the elevation of iron impurity,the band gap value decreases from 3.47 eV for the pure sample to 2.95 eV for the 10 mol% Fe-doped TiO_2 NPs.

Anti-UV Capability of Rare Earth Doping TiO_2

The sol-gel process is used in the preparation of nanostructure materials with Ti(OC_ 4 H_ 9 )_ 4 as precursor in the start materials. TiO_ 2 gelatin is obtained through hydrolysis and condensation process. Rare earth such as La_ 2 O_ 3 , CeO_ 2 , Eu_ 2 O_ 3 and Gd_ 2 O_ 3 are introduced into the nanostructure TiO_ 2 to improve the anti-UV capacity. The phase structure of pure TiO_ 2 and doped TiO_ 2 and their anti-UV capacity are studied by means of XRD and UPF. The optimum doping and heat treatment temperature are chosen.

Synthesis and Characterization of Titania and Rare Earth Doped Titania Nanoparticles by Sol-gel Process

Titania sol has been prepared by the sol-gel process with Ti（OC4H9）4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into the nanostructure TiO2. After TiO2 and rare earth doped TiO2 powders were calcined at 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, the characteristic analyses of the TiO2 samples were studied by UV-VIS, XRD and TEM etc. It was found that there are some stringer absorption peaks at 200 - 325 nm. The rare earth doping can increase the phase transition temperature convertin8 anatase phase into rutile phase, can decrease the grain size of TiO2particles and can improve the ann-UV capacity of the coating fabrics.

Bactericidal and Photoeatalytie Activity of Fe^(3+)-TiO_2 Thin Films Prepared by the Sol-gel Method

Pure TiO2 thin films and iron doped TiO2 thin films on glass substrate were prepared by sol-gel method, and characterized by X-ray diffractometer （XRD）, thermo-gravimetric analysis （TG-DSC）, high resolution transmission electron microscope （HRTEM）, scanning electron microscope （SEM） and UV-Vis spectroscopy, respectively. The experimental results show that the pure TiO2 thin films and iron doped TiO2 thin films can destroy most of the escherichia coli and bacillus subtillis under the irradiation of 365 nm UV-light. However, the iron doped TiO2 thin film is a better photocatalyst than pure TiO2 thin film. The ultrastructural studies provide direct evidences for understanding the bactericidal mechanism of the TiO2 photocatalyst.

Theoretic and Experimental Studies on Titania Nanotube Doped with Ag Metal Ions

The electronic state density and energy bands of Ag-doped anatase TiO2 are studied by WIEN2k software package based on DFT. The calculation results show that the band-gap of anatase titania became bigger after doping with Ag metal ions. The band-gap transfers from 2.04 to 2.5 eV, but a new energy band appears among the forbidden band after the Ag atom substitution. The interband width of Ag-TiO2 is 0.17 eV, which is located at –0.07 eV; more excitation and jump routes are opened for the electrons. The lowest excitation energy can achieve 1.2 eV, which may allow the photons with lower energy （at longer wavelength, such as visible light） to be absorbed. Ag ions are implanted into the titania nanotube sample by MEVVA （Metal Vapor Vacuum Arc） implanter. The photo-electrochemical response and photo-degradation experiment of titania nanotube samples implanted with Ag ions are tested under UV and visible light; the results indicated that the performance of implanted titania naotubes is enhanced both under UV and visible light; it is worth mentioning that the photocurrent density can reach 0.145 mA/cm2 under visible light, which is 181 times higher than those of pure TiNT, and the k value of degradation methyl orange can obtain 0.30 h-1, which is 71 times higher than that of pure TiNT. All the experimental results are consistent well with the theoretic ones.

Self-Cleaning Properties of Vanadium Doped TiO₂Sol-Gel Derived Thin Films

In this study, vanadium doped TiO2 thin films were deposited on glass substrates using a sol-gel dip-coating process. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectrophotometer were used to characterize the structural, chemical and the optical properties of the thin films. The photo-catalytic activities of films were investigated by methylene blue degradation. Water contact angle on the film surfaces was measured by a water contact angle analyzer. The results indicated that vanadium doping had a significant effect on the self-cleaning properties of TiO2 thin films.

Ag、N共掺杂TiO2漂浮型催化剂的光催化性能

采用溶胶-凝胶法,制备出银氮共掺杂TiO2负载膨胀珍珠岩的催化剂,通过电子显微镜扫描(SEM)、比表面积及孔径分析(BET)和X射线衍射(XRD)对其结构进行表征,并以罗丹明B溶液为目标降解物,研究所制备催化剂的光催化性能。结果表明:复合材料成功负载了Ag和N元素,且掺杂增强了TiO2对可见光的响应能力;复合材料存在少量的微孔和大孔,同时存在大量的介孔;掺杂氮后材料的光催化活性大幅度提高,继续掺杂Ag后光催化活性进一步提高,当n(Ag)∶n(Ti)=0.50%时光催化性能最佳,4h内处理罗丹明B降解率可达99.3%,材料的光催化反应符合一级反应动力学方程,表明其在环境净化实际应用中的巨大潜力。

Preparation and photocatalytic performance of Cu-doped TiO_2 nanoparticles

Cu-doped TiO2 nanoparticles with different doping contents from 0 to 2.0% （mole fraction） were synthesized through sol-gel method. X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and field emission scanning electron microscope （FE-SEM） were used to characterize the crystalline structure, chemical valence states and morphology of TiO2 nanoparticles. UV-Vis absorption spectrum was used to measure the optical absorption property of the samples. The photocatalytic performance of the samples was characterized by degrading 20 mg/L methyl orange under UV-Vis irradiation. The results show that the Cu-doped TiO2 nanoparticles exhibit a significant increase in photocatalytic performance over the pure TiO2 nanoparticles, and the TiO2 nanoparticles doped with 1.0% Cu show the best photocatalytic performance. The improvement in photocatalytic performance is attributed to the enhanced light adsorption in UV-Vis range and the decrease of the recombination rate of photoinduced electron-hole oair of the Cu-doped TiO2 nanoparticles.

掺杂Ag提升TiO_2纳米薄膜光电性能研究

采用sol-gel法制备出Ag掺杂的TiO_2纳米薄膜,利用SEM、XRD、UV-Vis、XPS及电化学工作站等对其光学及光电特性进行表征,研究了掺杂浓度及退火温度对材料晶体结构、光学特性及光电性能的影响规律。结果表明:Ag的掺杂提高了材料的晶相转变温度,降低了材料禁带宽度,使吸收带边发生红移(约40 nm),有效提高薄膜对太阳光的利用效率。当Ag掺杂浓度为摩尔分数0.5%,退火温度为500℃时,材料表现出最佳的光电活性,光电流密度达0.38×10^(–3)A/cm^2,相较于纯TiO_2薄膜的光电流密度增大约41%,光电性能得到显著提升且稳定性良好。

掺银TiO_2复合薄膜的制备和光催化性能的研究

研究了通过 sol- gel工艺在普通玻璃表面制备均匀透明的掺银锐钛矿型 Ti O2 光催化复合薄膜。研究表明 :Ti O2 复合薄膜由 Ti O2 球形颗粒组成 ,其颗粒大小在 5 0 nm～ 10 0 nm;薄膜的厚度每镀一次增加约 0 .0 9μm;薄膜中出现的锐钛矿在 (10 1)面具有一定的择优取向。甲基橙水溶液的光催化降解实验表明 :掺银 Ti O2 复合薄膜的表观降解速率常数明显高于未掺银 Ti O2 薄膜的表观降解速率常数 ,这为进一步提高 Ti O2 薄膜的光催化活性开辟了新的途径。

One step synthesis and characterization of copper doped sulfated titania and its enhanced photocatalytic activity in visible light by degradation of methyl orange

This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction （XRD）, Ultraviolet-Visible Diffuse Reflection Spectroscopy （UV-Vis DRS）, X-ray Photoelectron Spectroscopy （XPS）, Scanning Electron Microscopy （SEM）, Energy Dispersive Spectrometry （EDS）, Fourier Transform Infrared Spectroscopic Studies （FT-IR）, and Transmission Electron Microscopy （TEM）. From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region （red shift）, the entry ofCu2 ＋ into Ti02 lattice as a substitution- al dopant and S042- ions were covalently bonded with Ti4＋ on the surface of the copper doped titania respectively. The photocatalytic activity studies were investigated by considering methyl orange （MO） as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.