Preparation of re-usable photocatalytic filter for degradation of Malachite Green dye under UV and vis-irradiation

Sn(4+) doped and undoped nano-TiO(2) particles easily dispersed in water were synthesized without using organic solvent by hydrothermal process. Nanostructure-TiO(2) based thin films were prepared on flyswatter substrate, made with stainless steel, by dip-coating technique. The structure, surface and optical properties of the particles and thin films were characterized by element analysis and XRD, BET, SEM and UV/vis/NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and vis-lights. The results showed that the coated flyswatter has a very high photocatalytic performance for the photodegradation of Malachite Green irradiated with UV and vis-lights. The results also proved that the hydrothermally synthesized nano-TiO(2) particles are fully anatase crystalline form and are easily dispersed in water, the coated surfaces are hydrophilic, and the doping of transition metal ion efficiently improved the degradation performance of TiO(2)-coated flyswatter. The photocatalytic performances determined at both irradiation conditions were very good and were almost similar to each other for Sn(4+) doped TiO(2)-coated flyswatter and it can be repeatedly used with increasing photocatalytic activity compared to undoped TiO(2)-coated flyswatter.     

Photocatalytic performance of Sn-doped and undoped TiO2 nanostructured thin films under UV and vis-lights

Sn-doped and undoped nano-TiO(2) particles have been synthesized by hydrotermal process without solvent at 200 degrees C in 1h. Nanostructure-TiO(2) based thin films have been prepared on glass substrate by spin-coating technique. The structure, surface morphology and optical properties of the thin films and the particles have been investigated by element analysis and XRD, SEM, BET and UV-vis-NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and vis-lights. The results showed that (a) hydrothermally synthesized nano-TiO(2) particles are fully anatase crystalline form and are easily dispersed in water, (b) the coated surfaces have nearly super-hydrophilic properties and, (c) the doping of transition metal ion efficiently improved the photocatalytic performance of the TiO(2) thin film.     

Photocatalytic antibacterial performance of Sn(4+)-doped TiO(2) thin films on glass substrate

Pure anatase, nanosized and Sn(4+) ion doped titanium dioxide (TiO(2)) particulates (TiO(2)-Sn(4+)) were synthesized by hydrothermal process. TiO(2)-Sn(4+) was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn(4+) doping to TiO(2) against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO(2)-Sn(4+) in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO(2)-Sn(4+) is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO(2)-Sn(4+) from 10 to 50% in the coating solution increased antibacterial effect.     

Solvothermal synthesis of crystalline phase and shape controlled Sn(4+)-doped TiO2 nanocrystals: effects of reaction solvent

The Sn(4+)-doped TiO(2) nanocrystals with controlled crystalline phase and morphology had been successfully prepared through easily adjusting the solvent system from the peroxo-metal-complex precursor by solvothermal method. The Sn(4+)-doped TiO(2) nanocrystals were characterized by XRD, Raman, TEM, HRTEM, XPS, ICP-AES, BET, and UV-vis. The experimental results indicated that the Sn(4+)-doped TiO(2) nanocrystals prepared in the pure water or predominant water system trend to form rodlike rutile, whereas the cubic-shaped anatase Sn(4+)-doped TiO(2) nanocrystals can be obtained in the alcohol system. The growth mechanism and microstructure evolution of the Sn(4+)-doped TiO(2) nanocrystals prepared in the different solvent systems are discussed. The liquid-phase photocatalytic degradation of phenol was used as a model reaction to test the photocatalytic activity of the synthesized materials. It was found that sample Sn(4+)-doped TiO(2) prepared in 1-butanol showed the maximum photoactivity, which attributed to higher band gap, optimal crystalline phase and surface state modifications.     

Photocatalytic performance of Sn-doped TiO2 nanostructured thin films for photocatalytic degradation of malachite green dye under UV and VIS-lights

Sn-doped and undoped nano-TiO₂ particles have been synthesized by hydrotermal process without acid catalyst at 225 °C in 1 h. Nanostructure-TiO₂ based thin films, contain at different solid ratio of TiO₂ in coating, have been prepared on glass surfaces by spin-coating technique. The structure, surface morphology and optical properties of the thin films and the particles have been investigated by element analysis and XRD, BET and UV/VIS/NIR techniques. The photocatalytic performance of the films was tested for degradation of malachite green dye in solution under UV and VIS-lights. The results showed that the hydrothermally synthesized nano-TiO₂ particles are fully anatase crystalline form and are easily dispersed in water, the coated surfaces have nearly super-hydrophilic properties and, the doping of transition metal ion efficiently improved the photocatalytic performance of the TiO₂ thin film. The results also proved that malachite green is decomposed catalytically due to the pseudo first-order reaction kinetics.     

掺铁二氧化钛薄膜的自组装制备和光催化性能研究

以TiCl4为钛源,SAMs为模板,Fe（NO3）3·9H2O为铁源,采用自组装方法于低温液相反应体系中分别成功地制备出大面积二维结构纳米的纯净和掺铁Ⅱ0：薄膜,通过拉曼光谱、高分辨透射电镜、荧光发射光谱等方法对样品进行表征,研究紫外光和可见光下纳米薄膜对甲基橙溶液的光催化降解过程以及紫外光下对甲苯的降解效率,探讨了掺铁后对TiO2：的光催化活性的影响,结果表明,此方法不需要高温煅烧即可得到高催化活性的以金红石为主的掺铁二氧化钛纳米薄膜。     

柱状晶形貌TiO2膜厚对FTO/TiO2镀膜玻璃光催化活性影响

采用溶胶凝胶法,在FTO(SnO2:F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO2薄膜,获得双层结构FTO/TiO2镀膜玻璃样品.研究了TiO2薄膜厚度对FTO/TiO2镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响.结果表明,FTO/TiO2镀膜玻璃样品光催化活性随着TiO2薄膜厚度的增加先升高后下降,在TiO2薄膜厚度为300 nm时光催化活性最佳;低辐射性能随着TiO2薄膜厚度的增加而下降,但TiO2薄膜厚度为300 nm时仍然具备一定的低辐射性能;透光性能与TiO2薄膜膜厚的关系不大,可见光透射比保持在72%左右;表面平均粗糙度约为1 nm,表面光滑,不易沾染油污灰尘.该镀膜玻璃在保证低辐射建筑节能和透光的前提下,兼具光催化自清洁功能,具有很好的应用前景.     

复合电沉积制备SnO2/TiO2薄膜及其光电催化性能

为了寻求廉价、高效和稳定的光催化剂,用复合电沉积技术在紫铜片上制备了Sn/TiO2薄膜,经300℃热氧化使之形成SnO2/TiO2复合电极.利用SEM,XRD对薄膜进行了表征,以甲基橙为模型化合物,对复合电极的光催化和光电催化性能进行了测定.研究表明:该薄膜由0.3~1μm的颗粒构成,每个颗粒又由纳米晶粒形成;电极具有多孔结构,膜中的SnO2以两种不同的晶体结构存在;在薄膜质量相等的情况下,SnO2/TiO2薄膜的光催化活性是纯TiO2粒子膜的2.87倍;外加一定偏压下,其催化性能大幅度提高.     

HNO3处理对TiO2纳米薄膜的光催化活性和表面微结构的影响

通过sol-gel工艺分别在钠钙玻璃和预涂SiO2涂层的钠钙玻璃基体上制备了TiO2光催化纳米薄膜．然后用1mol／L HNO3水溶液对煅烧后的薄膜进行酸处理。用X射线光电子能谱(XPS)、扫描电镜(SEM)和紫外可见光谱(UV—VIS)对酸处理前后TiO2纳米薄膜进行了表征。用甲基橙水溶液的光催化脱色来评价TiO2薄膜的光催化活性。结果表明：SiO2涂层能有效阻止钠离子从玻璃基体向TiO2薄膜的扩散，普通玻璃表面的TiO2纳米薄膜经HNO3处理后，薄膜的光催化活性明显增强。这是由于TiO2纳米薄膜中的钠离子浓度降低以及表面羟基含量增加的缘故。     

Low-temperature preparation and characterization of iron-ion doped titania thin films

Iron-ion doped titania thin films with an anatase phase were successfully synthesized in this study using the high-pressure crystallization (HPC) process. The crystallization temperature of Fe(3+)-doped TiO(2) thin films was markedly reduced to be as low as 125 degrees C. The films prepared via the HPC process have a more uniform microstructure and smaller grain sizes than the films prepared via the atmospheric-pressure annealing process. The films prepared via both processes were found to have photocatalytic properties under visible light. The films prepared via the HPC process exhibited enhanced photocatalytic activities in comparison with the films annealed via the conventional process. Increasing the annealing temperature in the HPC process resulted in an improvement in the photocatalytic properties because of an increase in the crystallinity of the prepared films. The HPC process was demonstrated to be a potential method for synthesizing visible-light driven titania thin films with enhanced photocatalytic activities at low temperatures.     

Fe2O3/TiO2和ZnO/TiO2纳米颗粒薄膜的亲水性能和光催化性能的研究

采用溶胶-凝胶法在玻璃上制备了锐钛矿型TiO_2和过渡金属铁、锌离子掺杂的TiO_2薄膜,并通过XRD、XPS、AFM表征了合成的薄膜。结果表明铁和锌离子掺入后,TiO_2薄膜变的更加致密。铁离子和锌离子分别以Fe_2O_3和ZnO的形式存在,在紫外光照射下,TiO_2薄膜表现明显的亲水性,金属离子掺杂的TiO_2薄膜,亲水性能明显增强,铁离子掺入对光催化降解甲基橙有一定的抑制作用;少量的锌离子掺入对光催化降解甲基橙有促进作用,锌离子掺入量增大后,效果并不明显。     

离子注入改善纳米二氧化钛薄膜光催化性能

利用直流磁控反应溅射技术在玻璃衬底上制备了透明的纳米TiO2光催化薄膜。利用离子注入技术将Sn离子注入到TiO2表面以提高其光催化活性。用X射线衍射（XRD）、X射线光电子谱（XPS）以及UV－VIS分光光度计对薄膜进行结构与性能表征。Sn离子注入后的薄膜具有更高的光催化活性，这是因为在TiO2和SnO2半导体的复合体系中，电子－空穴对的分离变得更加有效，从而提高了其催化性能。     

Photocatalytic activity of nanosized TiO2 thin film prepared by magnetron sputtering method

Nanosized TiO2 thin film on the substrate such as stainless steel plate and slide glass film were prepared by magnetron sputtering method, and these TiO2 thin films were characterized by field emission-scanning electron microscopy (FE-SEM). Photocatalytic activity for Methyl-ethyl-ketone (MEK) and acetaldehyde were measured using a closed circulating reaction system through the various ultra violet (UV) sources. From the results of SEM images, nanosized TiO2 thin film was uniformly coated on slide glass, ranging from 360 nm to 370 nm. Photocatalytic activity of MEK over TiO2 thin film on stainless steel plate did not occur by UV-A irradiation, but was efficiently decomposed by UV-B and UV-C. Also, acetaldehyde could be decomposed than MEK. The effect of sputtering conditions on their structure and photocatalytic activities were investigated in detail.     

纳米TiO2 / 再生纤维素复合薄膜的制备及光催化性能

在1-烯丙基-3-甲基咪唑氯室温离子液体中, 将纳米TiO₂粉末与纤维素浆粕进行溶液共混, 所得纤维素用水再生后, 经过超临界CO₂干燥处理, 制备了不同TiO₂ 含量的纳米TiO₂ / 再生纤维素复合膜。通过扫描电子显微镜(SEM) 、X 射线衍射(XRD) 、傅立叶变换红外光谱( FTIR) 对所得薄膜的形貌、结构进行表征。利用PCC-2 型光催化活性检测仪测试薄膜在紫外光下光催化降解亚甲基蓝的能力, 评价薄膜的光催化活性。讨论了纳米TiO₂ 含量、超临界CO₂ 干燥和真空干燥对薄膜性能的影响。结果表明: 复合膜的光催化活性达到所用TiO₂粉体的90 %; 经超临界CO₂ 干燥处理所得复合膜的光催化活性明显高于真空干燥所得复合膜的活性; 纳米复合膜的光催化活性随TiO₂ 含量的增加先升高后降低, 含量为5 %时光催化活性最高。      

Fabrication of SiO<Subscript>2</Subscript>/TiO<Subscript>2</Subscript> double layer thin films with self-cleaning and photocatalytic properties

Transparent antireflective SiO₂/TiO₂ double layer thin films were prepared using a sol–gel method and deposited on glass substrate by spin coating technique. Thin films were characterized using XRD, FE-SEM, AFM, UV–Vis spectroscopy and water contact angle measurements. XRD analysis reveals that the existence of pure anatase phase TiO₂ crystallites in the thin films. FE-SEM analysis confirms the homogeneous dispersion of TiO₂ on SiO₂ layer. Water contact angle on the thin films was measured by a contact angle analyzer under UV light irradiation. The photocatalytic performance of the TiO₂ and SiO₂/TiO₂ thin films was studied by the degradation of methylene blue under UV irradiation. The effect of an intermediate SiO₂ layer on the photocatalytic performance of TiO₂ thin films was examined. SiO₂/TiO₂ double layer thin films showed enhanced photocatalytic activity towards methylene blue dye.     

Ag/TiO2薄膜结构和光催化性能研究

采用溶胶-凝胶技术制备了Ag掺杂的TiO2薄膜.用XRD、氮吸附法、UV-VIS-NIR分光光度计以及XPS对Ag掺杂后TiO2薄膜结构的变化进行了分析;用分光光学法通过在紫外光照下分解亚甲基蓝的实验比较了TiO2薄膜与Ag/TiO2薄膜的光催化性能.结果发现,掺杂适量的Ag有助于TiO2薄膜光催化氧化性能的提高,原因在于:（1）Ag通过引入耗尽层提高了TiO2的电荷分离能力,并吸引空穴向薄膜表面移动,结果使薄膜表面空穴的浓度提高,薄膜光催化效率提高;（2）Ag减小了TiO2粒子的粒径,使TiO2禁带宽度增大,薄膜光催化氧化的能力提高;（3）Ag掺杂后,TiO2薄膜表面对-OH基和水的吸附增加,使光照后TiO2薄膜表面活性自由基·OH的浓度增加,空穴向薄膜所吸附物质的转移能力提高.     

Photocatalytic TiO(2) deposition by chemical vapor deposition

Dip-coating, spray-coating or spin-coating methods for crystalline thin film deposition require post-annealing process at high temperature. Since chemical vapor deposition (CVD) process is capable of depositing high-quality thin films without post-annealing process for crystallization, CVD method was employed for the deposition of TiO(2) films on window glass substrates. Post-annealing at high temperature required for other deposition methods causes sodium ion diffusion into TiO(2) film from window glass, resulting in the degradation of photocatalytic efficiency. Anatase-structured TiO(2) thin films were deposited on window glass by CVD, and the photocatalytic dissociation rates of benzene with CVD-grown TiO(2) under UV exposure were characterized. As the TiO(2) film deposition temperature was increased, the (112)-preferred orientations were observed in the film. The (112)-preferred orientation of TiO(2) thin film resulted in a columnar structure with a larger surface area for benzene dissociation. Obviously, benzene dissociation rate was maximum when the degree of the (112) preferential orientation was maximum. It is clear that the thin film TiO(2) should be controlled to exhibit the preferred orientation for the optimum photocatalytic reaction rate. CVD method is an alternative for the deposition of photocatalytic TiO(2).     

SnP2+-TiO2的可见光催化活性及其在介孔蒙脱石上的负载

分别以氯化锡和氯化亚锡为Sn源,使用溶胶-凝胶法制备出不同掺杂量的Sn-TiO2,比较了Sn2+与Sn4+对掺杂后TiO2可见光催化活性的影响.实验结果显示,Sn2+与Sn4+均能显著抑制TiO2晶粒生长,并促进其晶型转变.但Sn2+-TiO2的可见光催化活性却明显优于Sn4+-TiO2,这主要是Sn2+外层半充满的电子轨道结构引起的.将可见光催化活性很高的Sn2+-TiO2负载于大比表面积、高稳定性的介孔蒙脱石上,由于载体与Sn-TiO2之间发生了相互作用,负载后样品的UV-Vis光谱吸收边相对于Sn-TiO2发生了显著红移,且可见光催化活性也有大幅提高.     

Effects of calcination temperatures on photocatalytic activity of SnO2/TiO2 composite films prepared by an EPD method

SnO2/TiO2 composite films were fabricated on transparent electro-conductive glass substrates (F-doped SnO2-coated glass:FTO glass) via an electrophoretic deposition (EPD) method using Degussa P25 as raw materials, and were further characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM), UV-vis diffuse reflectance spectra and Photoluminescence spectra (PL). XRD and XPS results confirmed that the films were composed of TiO2 and SnO2. FESEM images indicated that the as-prepared TiO2 films had roughness surfaces, which consisted of nano-sized particles. The effects of calcination temperatures on the surface morphology, microstructures and photocatalytic activity of SnO2/TiO2 composite films were further investigated. All the prepared SnO2/TiO2 composite films exhibited high photocatalytic activities for photocatalytic decolorization of Rhodamine-B aqueous solution. At 400 degrees C, the SnO2/TiO2 composite films showed the highest photocatalytic activity due to synergetic effects of low sodium content, good crystallization, appropriate phase composition and slower recombination rate of photogenerated charge carriers.     

Effect of surface fluorination of TiO2 particles on photocatalitytic activity of a hybrid multilayer coating obtained by sol-gel method

A multilayer photoactive coating containing surface fluorinated TiO(2) nanoparticles and hybrid matrices by sol gel approach based on renewable chitosan was applied on poly(lactic acid) (PLA) film by a step wise spin-coating method. The upper photoactive layer contains nano-sized functionalized TiO(2) particles dispersed in a siloxane based matrix. For the purpose of improving TiO(2) dispersion at the air interface coating surface, TiO(2) nanoparticles were modified by silane coupling agent 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FTS) with fluoro-organic side chains. An additional hybrid material consisting of chitosan (CS) cross-linked with 3-glycidyloxypropyl trimethoxy silane (GOTMS) was applied as interlayer between the PLA substrate and the upper photoactive coating to increase the adhesion and reciprocal affinity. The multilayer TiO(2)/CS-GOTMS coatings on PLA films showed a thickness of ~4-6 μm and resulted highly transparent. Their structure was exhaustively characterized by SEM, optical microscope, UV-vis spectroscopy and contact angle measurements. The photocatalytic activity of the multilayer coatings were investigated using methyl orange (MeO) as a target pollutant; the results showed that PLA films coated with surface fluorinated particles exhibit higher activity than films with neat particles, because of a better dispersion of TiO(2) particles. The mechanical properties of PLA and films coated with fluorinated particles, irradiated by UV light were also investigated; the results showed that the degradation of PLA substrate was markedly suppressed because of the UV adsorptive action of the multilayer coating.