三乙胺改性TiO_2光催化薄膜的制备与结构分析

采用溶胶-凝胶法,利用多水体系制备工艺制备了具有锐钛矿晶型的TiO2溶胶,通过三乙胺制备改性TiO2溶胶,最终制得具有可见光催化性能的TiO2复合薄膜。通过SEM、粒度分析、TEM等表征发现三乙胺的加入改变了TiO2晶粒尺寸和薄膜的结构。可见光催化实验表明:三乙胺与钛酸丁酯质量比为1:2时,薄膜光催化性能最优;利用UV-vis测试发现改性后的TiO2薄膜的吸收边有所红移,在可见光区具有较强的吸收。     

锐钛矿型TiO_2溶胶原位改性醋丙乳液的研究

采用TiOSO4为原料制备稳定的锐钛矿型TiO2溶胶,将其与醋丙乳液复合,原位合成含有锐钛矿型TiO2晶粒的复合乳液,并采用浸渍提拉法制备薄膜。分别采用XRD、TEM、SEM等测试手段对TiO2溶胶的物相结构、复合乳液中粒子的大小和形态、薄膜表面形貌等进行表征,并考察TiO2溶胶添加量对薄膜表面形貌、接触角以及光催化性能的影响。结果表明:该复合乳液具有较高的稳定性和良好的成膜特性,TiO2粒子在复合薄膜中分布均匀,随TiO2含量的增大,薄膜表面的TiO2粒子增多,导致薄膜粗糙度增大。经紫外光照后,复合薄膜对水的接触角随TiO2含量的增大而降低,光催化活性逐步提高。     

热处理温度对TiO2结构和光学性能的影响

为探索热处理温度对纳米TiO2性能的影响,研究了不同温度下处理的纳米TiO2的光学性能和微观结构,并进行了纳米TiO2光催化性能的实验.实验表明,所用的纳米TiO2溶胶可以在紫外光照射下分解甲基紫;由于粒子纳米化导致晶格畸变,纳米TiO2粒子的结晶峰出现宽化现象;热处理温度决定纳米TiO2的结晶程度和晶体类型,同时还影响粒子的粒径和分散热处理温度越高,粒子颗粒越大,同时团聚增加;粒子纳米化导致量子尺寸效应的出现,纳米TiO2薄膜对紫外线的吸收具有"蓝移"效应;随着热处理温度的升高,"蓝移"效应减弱,TiO2薄膜的紫外吸收边出现了"温升红移"现象.     

掺铁纳米TiO_2溶胶改性竹炭研究

采用溶胶-凝胶法常温制备掺铁纳米TiO2溶胶,分析掺铁纳米TiO2溶胶的光催化特性,并采用该溶胶对竹炭进行复合改性,阐明掺铁溶胶改性对竹炭的光催化特性及结构特征的影响机制。结果表明:掺铁纳米TiO2溶胶平均粒度在20nm,为锐钛矿晶型,具有优越的紫外光催化性能及可见光响应能力;掺铁溶胶改性竹炭后,TiO2颗粒主要富集在竹炭表面,赋予竹炭光催化性能,为竹炭长效去除污染、净化空气等功能的开发奠定基础。     

TiO2纳米晶薄膜溶胶凝胶法制备及其光学性能

通过溶胶凝胶浸渍提拉法成功制备了表面平整的氧化钛纳米晶薄膜.XPS结果确定了该薄膜的元素组成及价态.TG分析结果表明大量无定形Ti(OH)2向锐钛矿型TiO2转变发生在390℃左右.显微共焦Raman光谱确定了不同温度热处理所得薄膜的相结构.SEM形貌图显示TiO2薄膜表面粒子疏松,晶粒多在20nm～30nm之间.另外研究了Fe3+掺杂对TiO2薄膜光学吸收性能的影响.     

(Ni-Mo)-TiO2纳米薄膜的制备及其光催化降解罗丹明B的性能

以恒电流复合电沉积方法制备(Ni-Mo)-TiO2薄膜。采用SEM、XRD和DRS对薄膜的表面形貌、相结构和光谱特性进行表征,以罗丹明B为模拟污染物对薄膜的光催化活性进行测定,讨论罗丹明B溶液的pH值、通入气体以及不同辐射光波对薄膜光催化性能的影响,并推测光催化机理。结果表明:(Ni-Mo)-TiO2薄膜是由TiO2纳米粒子相和纳米晶Ni-Mo固溶体相构成的复合薄膜。薄膜具有较高的光催化活性,在可见光和紫外光照射下,罗丹明B的降解率分别为多孔P25 TiO2粒子薄膜的2.0倍和1.7倍。复合薄膜光催化活性的提高主要源于在薄膜层中能有效形成(Ni-Mo)/TiO2异质结和良好的电子通道,它一方面可以促使光生电荷的分离,另一方面加速了氧气与激发电子的还原反应。     

TiO_2溶胶改性竹炭的高温活化研究

采用溶胶-凝胶法制备的纳米TiO2对竹炭进行改性,并对改性前后竹炭进行高温活化,分析溶胶改性及高温活化对竹炭比表面积、物相及显微结构、光催化特性的影响机制。结果表明:溶胶改性及高温活化使竹炭的比表面积急剧增大,竹炭颗粒表面和细胞壁上存在锐钛矿型和金红石型共存的TiO2粒子,防止结构塌陷,并赋予竹炭优越的光催化性能。     

镍离子掺杂TiO2涂层的制备及亲水性研究

目的 研究不同含量的镍离子掺杂对TiO2纳米涂层亲水性能的影响.方法 采用溶胶-凝胶法制备不同含量Ni2+掺杂TiO2纳米复合溶胶,通过浸渍提拉法在载玻片上成膜,经过热处理后,得到不同含量Ni2+掺杂TiO2复合涂层.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见光分光光度计(UV-Vis)、傅里叶变换红外光谱仪(FT-IR)和表面接触角仪,对掺杂不同浓度Ni2+后TiO2的晶型、涂层微观形貌、光吸收性能、结构组成和涂层亲水性等进行表征分析,从而确定最佳Ni2+浓度的复合涂层材料配方.结果 制备的TiO2主要由锐钛矿相和少量金红石相组成,Ni掺杂抑制了锐钛矿相向金红石相的转变.随着Ni含量的增加,TiO2晶粒尺寸逐渐降低.适量掺杂Ni2+制备的TiO2纳米涂层表面形貌光滑,粒子分布致密均匀.掺杂使吸收波长阈值向长波方向偏移,禁带宽度减小,在一定程度上提高了TiO2涂层的亲水性.当Ni2+掺杂质量分数为1.5％时,TiO2涂层亲水性最佳.结论 采用溶胶-凝胶法实现了镍离子掺杂TiO2的改性,掺杂Ni2+后,Ni2+/TiO2复合涂层的亲水性能明显提高.     

纳米TiO2薄膜的制备及自清洁性能研究

通过溶胶一凝胶法在普通钠钙玻璃表面制备均匀透明的纳米TiO2自清洁薄膜。探讨了薄膜制备的工艺条件，并利用X射线衍射（XRD）、紫外分光光度计对薄膜的晶型、晶粒大小和透光率进行了表征，研究了在紫外光照射下薄膜的光催化性能及亲水性能。结果表明，制得的TiO2薄膜具有较强的自清洁性能。     

Li+,Sb3+掺杂的TiO2纳米颗粒的制备及光催化性能

以钛酸四丁酯和LiNO3,SbCl3为原料,采用溶胶-凝胶法在较低的热处理温度下制备Li+,Sb3+掺杂的TiO2纳米颗粒,并研究了TiO2颗粒在自然光下催化降解甲基橙的情况.采用DTA、XRD、TEM及Raman光谱等研究测试手段,发现通过溶胶-凝胶法在TiO2溶胶中加入LiNO3的方法,可以降低TiO2从无定型到锐钛矿相的晶型转变温度,并在低温热处理条件下,获得光催化性能优异的锐钛矿相的TiO2粒子.通过甲基橙水溶液光催化实验表明适量的Li+和Sb3+的掺杂能提高TiO2粒子的自然光催化降解能力,适量的Li+和Sb3+的混合掺杂能进一步提高TiO2粒子的自然光催化降解能力.     

Corrosion resistance of anodized AZ31 Mg alloy in borate solution containing titania sol

Anodic films were prepared on the AZ31 magnesium alloy in alkaline borate solution with or without addition of titania sol under the constant potential of 50 V (dc) for 10 min at room temperature. The morphology of the anodic films was observed by scanning electron microscope (SEM). The corrosion resistance of the anodic films was evaluated in 3.5% NaCl solution using fast anti-acid test, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The anodic film formed in borate solution with addition of 4% titania sol has superior uniform surface and higher corrosion resistance than in other conditions.     

Phosphate coating on stainless steel prepared in electrolyte with silica sol: zinc segregation,post-treatment and corrosion resistance

Phosphate film is generally not compact, left with microscopic cracks or pores during the phosphating process. Silica sol is incorporated into the phosphating solution to fabricate phosphate films on stainless steel 316L by electrochemical method. It is found that at appropriate amount of silica sol (8 vol.-%), the cracks on the hopeite film are effectively filled, while they appear again when much more silica sol is added as observed by SEM images. Moreover, zinc is found simultaneously formed as detected by the energy dispersive spectroscopy and X-ray diffraction measurements. In order to improve the performances of the hopeite film, we use titania sol by dip coating to cover the hopeite film. The titania sol can improve the anticorrosion ability of the films with limited extent since its crack formation during curing. By adding polyvinyl butyral (2 wt-%) in this sol, the composite film exhibits great improvement in corrosion resistance resulting from the cracks remedy and synergy effect of zinc with titania gel.     

超支化聚氨酯/TiO2自清洁光固化涂层的制备及性能研究

采用溶胶-共混法制备超支化聚氨酯(UV-HPU)/TiO2自清洁光固化杂化涂层,在低温下(＜110℃)对涂层进行热处理.采用接触角方法研究不同TiO2溶胶添加量及热处理温度,对涂层光催化自清洁特性和基本性能的影响.结果表明:TiO2在涂料中的质量分数约为10％,热处理温度为110℃的涂层在紫外光照射后接触角可以达到3....     

Structural Characterization and Corrosion Behavior of Stainless Steel Coated With Sol-Gel Titania

Sol-gel titania films were prepared from hydrolysis and condensation of titanium (IV) isopropoxide. Diethanolamine was used as chelant agent in titania synthesis. 316L stainless steel substrates were dip-coated at three different withdrawal speeds (6, 30, and 60 mm/min) and heated up to 400 °C. Thermogravimetry and differential thermal analyses of the titania gel solution evinced a continuous mass loss for temperatures up to 800 °C. The transition of anatase to the rutile phase begins at 610-650 °C, being the rutile transformation completed at 900 °C. The thicknesses of the films were determined as a function of the heat treatment and withdrawal speed. It was observed that their thicknesses varied from 130 to 770 nm. Scanning electron microscopy images of the composites revealed the glass-like microstructure of the films. The obtained sol-gel films were also characterized by energy dispersive spectroscopy. The chemical evolution of the films as a function of the heating temperature was evaluated by Fourier transform infrared spectroscopy (specular reflectance method). After performing the adhesion tests, the adherence of the titania films to the stainless steel substrate was excellent, rated 5B according to ASTM 3359. The hardness of the ceramic films obtained was measured by the Knoop microindentation hardness test with a 10 g load. We observed that the titania film became harder than the steel substrate when it was heated above 400 °C. The corrosion rates of the titania/steel composites, determined from potentiodynamic curves, were two orders of magnitude lower than that of the bare stainless steel. The presence of the sol-gel titania film contributed to the increase of the corrosion potential in ca. 650 mV and the passivation potential in ca. 720 mV.     

Characterization of plasma electrolytic oxidation coatings formed on Mg–Li alloy in an alkaline polyphosphate electrolyte

Blue and white ceramic coatings have been successfully fabricated on the surface of Mg–Li alloys by plasma electrolytic oxidation (PEO) in an alkaline polyphosphate electrolyte with and without addition of titania sol. The influence of titania sol on the surface morphology, microstructure, phase composition, chemical composition, corrosion resistance, mechanical and tribological behavior of ceramic coatings was scrutinized by means of scanning electron microscopy (SEM), thin-film X-ray diffraction (TF-XRD), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization, nanoindentation measurements, and ball-on-cylinder friction testing. The blue ceramic coating containing MgO, TiO₂ and Ti₂O₃ phase exhibits better anticorrosion and tribological performance due to its higher nanohardness and lower friction coefficient.     

Thin nanocrystalline TiO2–SnO2 sprayed films: Influence of the dopant concentration,substrate and thermal treatment on the phase composition and crystallites sizes

Thin nanocrystalline TiO₂–SnO₂ films (0–50 mol% SnO₂) are coated on quartz and stainless steel substrates by spray pyrolysis method. The synthesized films are investigated by XRD, Raman spectroscopy and XPS.The diffraction peaks of anatase phase fade while the peaks of rutile phase appear in the X-ray profiles with increasing of the treatment temperature and the content of SnO₂ in the sprayed films. It is found that SiO₂ coming from the quartz substrate stabilizes the anatase phase up to 700 °C. A more pronounced crystallization of rutile is registered with the films deposited on stainless steel substrate, which probably is caused by combined effect of SnO₂ doping and penetration of iron and chromium from the substrate inside the films.Dopant concentration (SnO₂) influences the size of the crystallites of the titania films deposited on quartz substrates The size of crystallites in the titania films decreases from 45 to 25 nm with increasing of SnO₂ amount.The SnO₂ amount does not affects substantially the size of crystallites (about 23 nm) for the films deposited on stainless steel.     

Surface and interface analysis of HAP/TiO2 composite films on Ti6Al4V

The composite films constituted of hydroxyapatite (HAP) submicron particles embedded in the gel composed of the titania nanoparticles were prepared on commercial Ti6Al4V plates with titania buffer layer obtained by a spin-coating technique. The films were annealed in air at 450 ℃, 550 ℃ and 650 ℃, respectively. The phase formation, surface morphology, andinterfacial microstructure of the films were investigated by X-ray diffraction(XRD),Fourier transform infrared spectroscopy (FT-IR), field emission-scanning electron microscopy(FE-SEM) and energy dispersive X-ray (EDS) analysis. The results show that the as-prepared films are all well-crystallized, dense,homogeneous, and there was a close interfacial bond between the film and the substrate. The results of adhesion test indicate that there is a good bonding strength between the film and the substrate. The bone-like apatite formation on the surface of the films after immersion in acellular simulatedbody fluid(SBF) validated their bioactivities.     

Synthesis and photocatalytic properties of InVO4 sol containing nanocrystals by mild hydrothermal processing

The precursor precipitation of InVO₄ was synthesized by co-precipitation using indium trichloride (InCl₃), ammonium metavanadate (NH₄VO₃) and ammonia (NH₃H₂O) as raw materials. The InVO₄ sols with orthorhombic phase were obtained by hydrothermal treatment (the precursor precipitation solution at 423 K, for 4 h). The precursor and sol of InVO₄ were characterized by X-ray diffraction (XRD), Fourier Transform Infra-red spectra (FT-IR), scanning electron microscopy (SEM) measurements. The XRD patterns indicate that the InVO₄ precursor is amorphous phase, InVO₄ sol contains orthorhombic InVO₄ nanocrystals. The results also reveal that the pH value of the reaction mixture and reaction temperature play important roles to the target phase. InVO₄-TiO₂.thin films on glass slides were prepared by the dip-coating method from the composite sol. The photocatalytic properties of the InVO₄-TiO₂ thin films were investigated by the photocatalytic degradation of methyl orange solution. The results indicate that it has better photocatalytic activities than pure TiO₂ thin films or pure InVO₄ thin films with UV light.     

Effect of thermal treating temperature on characteristics of silver-doped titania

The silver-doped titania antibacterial agent was synthesized by mixing silver nitrate and the precursor of titania. Effects of thermal treatment on the properties of the silver-doped titania powders were investigated by thermal gravimeter/differential thermal analyzer（TG/DTA）, scanning electron microscope（SEM）, and X-ray diffractometer（XRD）, respectively. The results show that the anatase phase forms in titania when the powder is calcined at 400℃. With the increase of the calcination temperature from 400 to 700℃ , the grains of titania agglomerate and the particle size increases from 14 to 23 nm, and the specific surface area decreases from 63 to 38m^2g. As the powder is calcined at 700℃, titania starts to transform from anatase to futile phase. The release rate of silver ion of powder treated at the relatively low temperature is larger than that of powder treated at the relatively high temperature. The antibacterial tests show that the antibacterial activity of silver-doped titania powders is excellent against E.coli and S. aureus, and the antibacterial activity of powders weakens with the increase of the calcination temperature.     

Preparation and characterization of TiO2 photoelectrode codoped with aluminum and boron and its application in dye-sensitized solar cell

Nanocrystalline titania films codoped with aluminum and boron were prepared by cathodic vacuum arc deposition. In the process, titanium alloy target was used under an O2/Ar atmosphere, and sensitization of films were carried out by natural dye-sensitized complex in anhydrous ethanol. The structure, surface morphology and UV-vis spectra of titania films codoped were measured by X-ray diffraction analysis, scanning electron microscopy and ultraviolet-visible spectrometer. Theas-deposited films are found to be amorphous. The films annealed were examinedto be of anatase structure with orientation along the (101) planes, the averagecrystal size is in the range between 41 and 45 nm. SEM results show that thereare some pores in the codoped titania films, the optical properties of the dye-sensitized films were also measured which reveals that the spectral responses of films shift to the visible region. Under simulated sunlight illumination, the overall energy conversion efficiency of dye-sensitized nanocrystalline solar cell is 0.9%.