酸碱腐蚀对多孔TiO2薄膜透光率的影响

配制了含不同分子量聚乙二醇的TiO2溶胶，采用浸渍提拉法在普通载玻片上制备了单、双层多孔TiO2薄膜。用CA—A型接触角测量仪、SEM和UV／vis等研究了薄膜亲水性的变化、表面形貌以及酸碱腐蚀前后的光学特性。结果表明，所制备的薄膜表面呈微孔结构，可较长时间保持亲水性，具有较好的透光性，层数对透光率基本没有影响。经pH=3和pH=13的溶液浸泡60h，薄膜的透光率未发生变化，薄膜具有良好的耐酸碱腐蚀性。     

SiO_2添加量对TiO_2薄膜表面特征及亲水性的影响

采用溶胶凝胶法在载玻片表面制备了均匀透明的TiO2/SiO2超亲水性薄膜。利用XRD、红外光谱(IR)和分光光度计,研究了SiO2添加量对薄膜微结构、透光率、亲水性的影响。结果表明:添加SiO2后,薄膜中TiO2晶粒尺寸变小;在薄膜中,TiO2和SiO2分别单独形成颗粒,但有部分Ti—O—Si键形成,存在部分复合氧化物;由于取代反应,复合氧化物中表面形成Lewis酸,薄膜表面吸附的羟基含量增多且稳定,可提高TiO2薄膜的超亲水特性,其超亲水性状态在暗处可保持很长时间;SiO2添加量为40%时的薄膜亲水性最好。     

SiO2添加量对TiO2薄膜表面特征及亲水性的影响

采用溶胶—凝胶法在载玻片表面制备了均匀透明的TiO2／SiO2超亲水性薄膜。利用XRD、红外光谱(IR)和分光光度计，研究了SiO2添加量对薄膜微结构、透光率、亲水性的影响。结果表明：添加SiO2后，薄膜中TiO2晶粒尺寸变小；在薄膜中，TiO2和SiO2分别单独形成颗粒，但有部分Ti—O—Si键形成，存在部分复合氧化物；由于取代反应，复合氧化物中表面形成Lewis酸，薄膜表面吸附的羟基含量增多且稳定，可提高TiO2薄膜的超亲水特性，其超亲水性状态在暗处可保持很长时间；SiO2添加量为40％时的薄膜亲水性最好。     

基于 SiO2及表征气凝胶的玻璃超疏水化改性

采用溶胶-凝胶技术结合酸碱两步法制得SiO2醇凝胶分散液,然后通过简单的旋涂法和常压干燥技术在玻璃表面上构筑SiO2气凝胶薄膜,从而一步法实现玻璃表面低表面能物质的修饰和粗糙结构的构建,赋予玻璃表面超疏水、自清洁的特性。考察制备条件是否老化对玻璃表面形成的SiO2气凝胶薄膜性能的影响。结果表明,经过60℃老化后的SiO2凝胶,在玻璃表面制备出的SiO2气凝胶薄膜具有更加优异的超疏水性能,静态水接触角可以达到165.6°,滚动角小于1°。     

不锈钢表面TiO2薄膜的溶胶-凝胶法制备及其性能

通过溶胶-凝胶法在316L不锈钢表面制备TiO2薄膜.研究发现,经500℃热处理1h的TiO2主要由锐钛矿相构成,随着热处理温度的提高,锐钛矿相逐渐转变为金红石相.降解结晶紫水溶液和对水的接触角结果测试表明,随着涂膜次数的增加,TiO2薄膜的光催化性和亲水性都有一定的提高.电化学腐蚀测试说明,表面涂有TiO2薄膜的316L不锈钢的耐腐蚀性提高,薄膜对基体起到了一定的保护作用.     

涂层层数和保温时间对纳米TiO2薄膜显微结构的影响

用溶胶凝胶法和高温煅烧在玻璃基体上制备纳米TiO2 薄膜 ,测试在各种工艺条件下制备的薄膜的亲水性、紫外线激发活性等性能 ,利用X射线衍射法和扫描电镜法表征其显微结构 ,并重点进行了涂层层数和保温时间对显微结构性能影响的研究。结果表明 ,涂层层数增加和保温时间延长不影响涂层中锐钛矿晶型的稳定性 ,对纳米TiO2 的颗粒长大也无明显影响。     

溶胶-凝胶法制备TiO2-SiO2系亲水性薄膜的研究

采用溶胶-凝胶(sol-gel)法在陶瓷釉面砖表面制备了TiO2-SiO2系亲水性薄膜.利用XRD、AFM、FTIR、热显微镜润湿角测角仪等,研究了SiO2添加量对薄膜的微结构和亲水性等的影响.结果表明:薄膜中TiO2晶粒尺寸随着SiO2含量的增加而减小;TiO2和SiO2分别单独成相,并有Ti-O-Si键形成,存在部分复合氧化物,在光照条件下,由于取代反应,复合氧化物的表面易形成Lewis酸,薄膜表面吸附的羟基含量增多且稳定,SiO2摩尔分数为0.4时,润湿角小于5°,薄膜的超亲水状态可在停止光照后长时间存在.     

TiO_2薄膜光催化剂性能的研究

在空气环境下,通过浸涂的方法在普通玻璃基片(50mm×2mm×2mm)上采用溶胶-凝胶法制备了TiO2薄膜。通过XRD分析了TiO2薄膜处理温度对其结晶程度的影响。结果表明,增加热处理温度可以增加结晶的程度,甚至还会导致锐钛矿型向金红石型的晶相转变。此外,TiO2薄膜光催化性能的研究显示,TiO2薄膜的层数对其光催化性能具有明显的影响。增加薄膜的层数,TiO2薄膜对甲基橙的分解速率呈现出了一个逐步增加的趋势。当薄膜的层数达到4层和5层时,甲基橙的分解速率比较接近。然而不同的是,随着Ce或La的加入量的增加,掺杂Ce或La的TiO2薄膜对甲基橙的分解速率则呈现出了一个先增加后减小的趋势。     

浸渍提拉法合成Bi4Ti3O12基复合薄膜及其光催化性能

以TiO2、Bi4Ti3O12为原材料,采用浸渍-提拉法制备复合薄膜,研究了材料合成工艺对复合薄膜微观形貌、相结构及光催化性能的影响。XRD研究结果表明,合成的复合薄膜材料中含有正交相Bi4Ti3O12和锐钛矿TiO2两种晶相,Bi4Ti3O12沿垂直于玻璃基片的<001>方向取向生长。TiO2溶胶的浓度,Bi4Ti3O12的用量,以及表面活性剂的用量,拉膜次数对复合薄膜的成型有明显的影响,当TiO2溶胶的浓度为3mol/L、TiO2溶胶和Bi4Ti3O12质量比为10:1、表面活性剂的质量分数为3%、拉膜次数为3次的时候,合成的Bi4Ti3O12/TiO2复合薄膜较均匀且具有较优异的光催化性能。     

TiO2 / 玻璃鳞片复合颗粒的制备及抗渗透性能研究

目的制备TiO2/玻璃鳞片复合颗粒以改善玻璃鳞片与涂层的界面性能,提高复合涂层的抗渗透能力。方法利用溶胶回流法在玻璃鳞片表面制备一层TiO2薄膜,通过SEM,EDS以及XPS等技术表征TiO2薄膜的表面状态。制备复合涂层,利用EIS和盐雾试验测试TiO2/玻璃鳞片的抗渗透能力,并与玻璃鳞片的抗渗透性进行对比。结果玻璃鳞片表面被TiO2薄膜包覆,TiO2薄膜与玻璃鳞片表面以Si—O—Ti化学键连接,浸泡15 d后,玻璃鳞片涂层的Zw为8781Ω,TiO2/玻璃鳞片涂层的Zw为75234Ω。盐雾试验后,TiO2/玻璃鳞片涂层下的金属几乎没有腐蚀。结论玻璃鳞片经过TiO2包覆后,具有较强的抗渗透能力。     

Photocatalytic degradation of MO by complex nanometer particles WO3/TiO2

Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W^6＋ with TiO2 because the doped W^6＋ that entered into the crystal lattices of TiO2 led to the formation of defects in the crystal lattices of TiO2 and thereby improved the photocatalytic activity of TiO2.When WO3 doped in TiO2 exceeded 3%, the excess W^6＋ did not enter into the crystal lattices of TiO2 but were uniformly dispersed in TiO2 or they covered the surface of TiO2, which reduced the effective illumination area of TiO2 and thereby lowered the photocatalytic activity of TiOE.The relationship among the composition of the catalyst, the amount of photocatalyst, the illumination time, and the decolorizing rate of methyl orange （MO） were discussed. The results show that the decolorizing rate of MO can reach 82.3% using WO3/TiO2 as the photocatalyst, with the composition of WO3/TiO2 -3：97, the mass of catalyst = 0.400 g, the initial concentration of MO = 20 mg/L, pH = 6.5, and the illumina- tion time = 7 h.     

Metallization on polymer by catalyzation in supercritical CO2 and electroless plating in dense CO2 emulsion

In this study we propose a novel technique for electroless plating on polymer substrates using a dense CO₂ beyond the critical point. Ni–P thin films were fabricated by a novel, hybrid technique consisting of two processes: catalyzation in supercritical CO₂ with Pd bis-acetylacetonate and electroless plating in emulsion with dense carbon dioxide. These catalyzation processes were discussed by atomic force microscopic images and the roughness of the surface. Catalyzation in supercritical CO₂ enabled the nucleation of a large number of Pd nuclei on a polyimide substrate without chemical pretreatment, and the deposition of a uniform Ni–P metal film. Conventional catalyzation without chemical pretreatment led to the deposition of only a few nuclei in sparse, island-like formations. The deposition behavior of Pd nuclei in supercritical CO₂ was different from that in conventional catalyzation. When a polyimide was catalyzed in supercritical CO₂ and plated by conventional electroless plating in electrolyte solution, the plated film was pocked with small, peeled sections formed via the hydrogen bubbles of the sub-reaction and nodules formed via crystal growth of Ni–P. In contrast, the electroless plating in emulsion with dense CO₂ produced a uniformly plated film without peeling or nodules. The improved uniformity was attained by the solubility and diffusivity of the dense CO₂ beyond the critical point in the emulsion.     

TiO2-g-C3N4 composite materials for photocatalytic H2 evolution under visible light irradiation

In this investigation, we report the preparation of TiO₂-g-C₃N₄ composite materials with varying the wt.% of g-C₃N₄, the characterization of these materials by various techniques and photocatalytic hydrogen production under visible light irradiation in the presence of methanol. The X-ray powder diffraction (XRD) shows that the composite materials are consist of anatase TiO₂ and g-C₃N₄. Fourier transform infrared (FT-IR) spectra show that the absorbance band intensity of composite materials was stronger than that of C₃N₄. The UV-vis absorption spectra show that the absorption edge of the composite materials shifts to the lower energy region comparing to pure anatase and to longer wavelengths with increasing the amount of C₃N₄. The significant photoluminescence quenching was observed in TiO₂-C₃N₄ composite materials, indicating the charge transfer from C₃N₄ to TiO₂. The visible light induced H₂ evolution rate was remarkably enhanced by coupling TiO₂ with C₃N₄.     

Preparation of thermally stable anatase TiO2 photocatalyst from TiOF2 precursor and its photocatalytic activity

Preparation of anatase TiO₂ with high themal stability is of great importance for its environmental application. In this work, TiOF₂ was first synthesized by a simple microwave-assisted hydrothermal route using tetrabutyl titanate and hydrofluoric acid as precursors at 200 °C for 20 min. Then the resulted precipitates were calcined at different temperatures (300-1000 °C) for 2 h. The as-prepared samples were characterized by X-ray diffraction, Raman spectrum, scanning electron microscopy, N₂ adsorption-desorption isotherms and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated using Brilliant Red X3B, an anionic azo dye, as the target organic molecule under UV light irradiation. The results showed that the prepared TiOF₂ exhibited weak or no photocatalytic activity. The phase transformation of TiOF₂ to anatase TiO₂ occurred at about 300 °C. The prepared anatase TiO₂ from TiOF₂ showed very high thermal stability and the anatase-to-rutile phase transformation temperature was up to 1000 °C. Fluoride ions played an important role in the improvement of thermal stability of anatase TiO₂ by strongly adsorbing on the crystal planes of anatase to stabilize the anatase structure. The 700 °C-calcined sample showed the highest photocatalytic activity due to its relative good crystallization and high specific surface areas.     

Low temperature growth of nanocrystalline TiO2 films with Ar/O2 low-field helicon plasma

TiO₂ thin films were deposited on silicon wafer substrates by low-field (1 < B < 5 mT) helicon plasma assisted reactive sputtering in a mixture of pure argon and oxygen. The influence of the positive ion density on the substrate and the post-annealing treatment on the films density, refractive index, chemical composition and crystalline structure was analysed by reflectometry, Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD). Amorphous TiO₂ was obtained for ion density on the substrate below 7 × 10¹⁶ m^− 3. Increasing the ion density over 7 × 10¹⁶ m^− 3 led to the formation of nanocrystalline (~ 15 nm) rutile phase TiO₂. The post-annealing treatment of the films in air at 300 °C induced the complete crystallisation of the amorphous films to nanocrystals of anatase (~ 40 nm) while the rutile films shows no significant change meaning that they were already fully crystallised by the plasma process. All these results show an efficient process by low-field helicon plasma sputtering process to fabricate stoichiometric TiO₂ thin films with amorphous or nanocrystalline rutile structure directly from low temperature plasma processing conditions and nanocrystalline anatase structure with a moderate annealing treatment.     

O2 plasma treatment of mesoporous and compact TiO2 photovoltaic films: Revealing and eliminating effects of Si incorporation

Radio frequency (13.56 MHz) O₂ plasmas were used to modify the surface of mesoporous and compact TiO₂ films. The effects of substrate location in the plasma, applied rf power, and plasma mode (pulsed or continuous wave) were explored. X-ray photoelectron spectroscopy, contact angle measurements, and scanning electron microscopy were used to characterize changes to the TiO₂ films. For mesoporous materials, O₂ plasma treatment was found to increase oxygen content in the films, but Si content increased with applied rf power as a result of sputtering and redeposition of Si species from the reactor walls. XPS depth profiling using ion sputtering as well as O₂ plasma treatment of dyed materials revealed that Si was deposited throughout the mesoporous network, not as a surface SiO₂ layer. Pulsing the plasma with pulse duty cycles < 40% resulted in the elimination of Si and a reduction of damage in the modified films.     

Impregnation of Ni-P metal into polymer substrate via catalyzation in Sc-CO2 and electroless plating in Sc-CO2 emulsion

In this study we investigated the impregnation of Ni-P metal into polymer substrate via catalyzation in supercritical carbon dioxide (Sc-CO₂) and electroless plating in Sc-CO₂ emulsion, in comparison with calculated CO₂ diffusion in polymer on the basis of Fick's law. Sc-CO₂ has two major effects, high diffusivity and good chemical affinity with polymer, on the impregnation of Ni-P metal into the polyimide substrate. Our group fabricated an Ni-P thin film in Sc-CO₂ with an electroless plating emulsion after catalyzing the Sc-CO₂ with Pd complex. According to an EDX analysis, an increase in the Sc-CO₂ catalyzation time led to increases in both the intensity and depth of the Ni-ion penetration into the polyimide. We found that the impregnation reaction of Ni by our novel method is CO₂ diffusion controlling reaction. To clarify which of the two Sc-CO₂ properties, diffusivity or chemical affinity, played a dominant role, we conducted an electroless plating reaction with emulsion using hexane as the catalyzation solvent whose diffusivity is lower than that of Sc-CO₂. The good affinity with polyimide in the hexane catalyzation led to a film fabrication of Ni-P thin films, but numerous cracks were visible on the films under microscopic observation. According to an EDX analysis of the Ni-P catalyzed in hexane, the intensity of the penetrated Ni-ions into the polyimide was very low. The high diffusivity of the Sc-CO₂ promoted the penetration of the Pd catalyst and Ni-P electroless plating solution into the polyimide substrate.     

Surface morphology and structure of Ni-P, Ni-P-ZrO2, Ni-W-P, Ni-W-P-ZrO2 coatings deposited by electroless method

Electroless binary Ni-P and ternary Ni-W-P alloy coatings and electroless composite (Ni-P-ZrO₂ and Ni-P-W-ZrO₂) nickel coatings were deposited. Baths with aminoacetic acid as the complexing agent were used. ICP measurements showed that the P content depending on the type of coating is in a range of 4.7-6.3 wt.% (at pH = 6, t = 75 °C). The tungsten content is around 1-2 wt.%. SEM examinations show that the electroless Ni-P coating has the most fine-grained structure. Grains in the form of microspheroids 20 μm in size are characteristic of the Ni-P-ZrO₂ coating. X-ray diffraction patterns show that for all the obtained coatings peak Ni(111) located around 2θ = 44° is the most intensive. After the coatings are heat treated at 400 °C for 1 h the peak becomes even sharper. The heat treatment results in a nearly double increase in crystallite size. The quaternary coatings' abrasion resistance is determined by the second-phase (ZrO₂) particles present in them.     

Crystal structures and structural relationships of KFe2(SeO2OH)(SeO3)3 and SrCo2(SeO2OH)2(SeO3)2

The new phases KFe₂(SeO₂OH)(SeO₃)₃ and SrCo₂(SeO₂OH)₂(SeO₃)₂ have been synthesized under low-hydrothermal conditions and their structures were determined by single-crystal X-ray methods. Both compounds are monoclinic; KFe₂(SeO₂OH)(SeO₃)₃: space group P2, A = 9.983(4), B = 5.270(1), C = 10.614(4) Å, β = 97.42(2)°, V = 553.7 ų, Z = 2; SrCo₂(SeO₂OH)₂(SeO₃)₂: space group P2ln, A = 14.984(2), B = 5.286(1), C = 13.790(2) Å, β = 94.72(1)°, V = 1088.5 ų , Z = 4. The refinements converged to R-values of 2.9 and 3.6% respectively.

The atomic arrangement in KFe₂(SeO₂OH)(SeO₃)₃ and SrCo₂(SeO₂OH)₂(SeO₃)₂ is based on isolated MO₆ octahedra (M = Fe³⁺, Co²⁺), which are corner-linked via trigonal pyramidal selenite groups to a framework structure. Interstitials are occupied by potassium or strontium atoms in ten- or eight-coordination respectively, and by the lone-pair electrons of the Se⁴⁺ atoms. Both compounds are not isotypic but are closely related and may be interpreted as different distortions of an idealized structure type in space group P2/m, which was modelled for a theoretical compound SrFe₂(SeO₃)₄ by distance least squares refinement (program ).     

CC/PANI/TiO2复合材料的制备及其光催化性能研究

先采用原位聚合的方法在碳布上负载聚苯胺,然后利用溶剂热法在制备的碳布/聚苯胺(CC/PANI)复合材料上生长二氧化钛纳米片,得到了可便捷分离的CC/PANI/TiO₂复合光催化材料。通过SEM、XRD、UV、FTIR、XPS等手段对所制备的样品进行了形貌和结构表征,并比较了CC/PANI/TiO₂复合材料和纯TiO₂紫外-可见光条件下催化降解RhB的活性差异,结果表明CC/PANI/TiO₂复合材料具有比TiO₂更优异的光催化活性。光致发光光谱说明CC/PANI/TiO₂复合材料的发光强度比纯TiO₂的弱,有效抑制了光生载流子的复合;瞬态光电流响应和电化学阻抗谱(EIS)证明CC/PANI/TiO₂纳米复合材料更有效促进电子-空穴对分离和提高转移效率;活性物质捕捉实验证实?OH和?O_2^-是复合材料光催化降解RhB过程中的主要活性物质。CC/PANI/TiO₂复合材料循环利用6次后,仍然具有较高的催化活性,显示了其在污水处理领域中的良好应用前景。