Ag掺杂纳米二氧化钛的制备及光催化性能研究

采用溶胶-凝胶法制备了Ag掺杂纳米二氧化钛。采用SEM、XPS、XRD、UV-Vis对样品进行表征。结果表明,未掺杂的样品的粒径在80～100nm,Ag掺杂的样品的粒径在40～50nm;Ag元素成功进入晶格,含量为0.67%(原子分数);400℃热处理时,掺杂与未掺杂样品晶型基本相同,600℃热处理时,掺杂能够抑制样品晶型的转变;掺杂使二氧化钛的吸收带边发生了一定的红移。在此条件下Ag的最佳掺杂量为0.5%,最佳热处理温度为600℃。在最佳条件下,以甲基橙为模拟污染物,经过120min的光催化实验,降解率达到97.9%。     

Dye-sensitized TiO2 film with bifunctionalized zones for photocatalytic degradation of 4-cholophenol

A new strategy to photocatalytic degradation of 4-cholophenol (4-CP) under visible light irradiation was described. The TiO₂ film deposited on an ordinary glass sheet was distributed into two zones. One zone was sensitized by N719 dye and fabricated to be a sandwich type cell with a similar structure of dye-sensitized solar cells. The other zone was inserted into pollutants solution for degradation. A highly oxidized overvoltage anode was achieved from the dye-sensitized zone. The bifunctionalized TiO₂ film and the anode could degrade 4-chlorophenol in two separate reactors with 97% and 96% removal of 4-CP after 5 h, respectively. The degradation efficiency could be improved by addition of FeSO₄. The as-prepared bifunctionalized TiO₂ film was comparably stable in the process of degradation.     

磁控反应溅射不锈钢表面制备纳米TiO2薄膜及光催化活性研究

不锈钢箔片上溅射沉积25nm的钛底膜后,在工作真空0．9Pa．O2、Ar分压比1：6．基体温度270～280℃的条件下,用直流磁控反应溅射法制备了厚度约300nm的TiO2薄膜,并在420℃的氧气氛下进行热处理。XRD分析看出,薄膜为TiO2锐钛矿和金红石复合晶型。测算表明TiO2复合晶中锐钛矿质量含量约64％,其晶粒尺寸约14nm。用“弯曲法”测试表明,膜基结合力强。由对苯酚溶液的降解实验看出,制备光催化薄膜具有较好的光催化活性。     

TiO_2-(线性低密度聚乙烯-g-马来酸酐)/低密度聚乙烯薄膜的制备及其光催化降解性能

以线性低密度聚乙烯(LLDPE)-g-马来酸酐(MA)作为相容剂制备了可光催化降解的TiO_2-(LLDPE-gMA)/LDPE薄膜。采用SEM、XRD、FT-IR对制备的TiO_2-(LLDPE-g-MA)/LDPE薄膜样品进行了表征。由于引入的LLDPE-g-MA改善了纳米TiO_2与LDPE之间的相容性,TiO_2-(LLDPE-g-MA)/LDPE薄膜具有更高的伸长率。SEM结果显示,LLDPE-g-MA显著削弱了纳米TiO_2在LDPE中的团聚,使高分散度的纳米TiO_2具备更高的光催化降解效率,增加了降解过程中的膜质量的损失。     

Improved photocatalytic activity of zeolite- and silica-incorporated TiO2 film

Porous TiO2 film was prepared by sol-gel method from TiO2 sol containing polyvinylpyrolidone (PVP). Photocatalytic activity of the film was evaluated by the elimination rate of ethylene. Several adsorbents including zeolite and silica powders were incorporated into the TiO2 film. All the adsorbents enhanced the activity. The optimum adsorbent content was 0.005-0.01 g/ml of the coating sol solution. Silica provided better activity than zeolite. At high humidity and in dry air the activity decreased.     

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。     

Enhanced TiO2 photocatalytic degradation of bisphenol E by beta-cyclodextrin in suspended solutions

Enhancement of beta-cyclodextrin (beta-CD) on TiO(2) photocatalytic degradation of bisphenol E (BPE, bis(4-hydroxyphenyl)ethane) was investigated under a 250 W metal halide lamp (lambda> or =365 nm) in this work. In the system of photocatalytic degradation of BPE, the photodegradation rate of BPE in aqueous solutions containing beta-CD and TiO(2) was obviously faster than that in aqueous solutions containing only TiO(2). After 40 min of irradiation, beta-CD could increase the photodegradation efficiency by about 26% for 10 mg l(-1) BPE in the UV-vis/TiO(2) system and the photodegradation of 2.5-20.0 mg l(-1) BPE in aqueous solutions was found to follow pseudo-first-order law and the adsorption constant and the reaction rate constant of BPE in the system containing beta-CD and TiO(2) are obviously higher than those in the system containing only TiO(2), the influence factors on photodegradation of BPE were studied and described in details, such as beta-CD concentration, pH, BPE initial concentration and gas medium. The formation of CO(2) as a result of mineralization of BPE was observed during the photodegradation process. After 120 min of irradiation, the mineralization efficiency of BPE reached 61% in the presence of beta-CD, whereas mineralization efficiency was only 23% in the absence of beta-CD. The enhancement of photodegradation of BPE could be dependent on the enhancement of adsorption of BPE on TiO(2) surface and moderate inclusion-depth of BPE in the beta-CD cavity.     

TiO2 mediated photocatalytic degradation studies of Reactive Red 198 by UV irradiation

Photocatalytic degradation of an aqueous solution of azo dye (Reactive Red 198) used in textile industries by UV irradiation was investigated. The effect of initial dye concentration, TiO(2) loading, pH and H(2)O(2) on degradation rate was ascertained and optimized conditions for maximum degradation were determined. The kinetics of photocatalytic degradation was found to follow a pseudo-first order according to Langmuir-Hinshelwood model. The degradation experiment under optimized reaction conditions was investigated under sunlight.     

V-N共掺杂TiO_2/玻璃珠光催化复合材料的制备及光催化性能

用溶胶-凝胶法制备V-N-TiO_2/玻璃珠光催化复合材料,研究V-N-TiO_2(V-N-TiO_2)的浓度、V-N-TiO_2/玻璃珠的浸渍次数、玻璃珠尺寸、煅烧温度和煅烧时间对V-N-TiO_2/玻璃珠光催化复合材料光催化性能的影响。采用XRD、EDS、TEM、XPS等测试手段对复合材料的结构和性能进行表征;在100 W汞灯下,以苯酚溶液为目标降解物,对V-N-TiO_2/玻璃珠光催化复合材料光催化性能进行测定。研究表明:当V-N-TiO_2/玻璃珠的浸渍次数为4次、玻璃珠尺寸为2~3mm、煅烧温度为400℃和煅烧时间为4.5h时,得到的V-N-TiO_2/玻璃珠光催化复合材料对苯酚的光催化性能最佳,且单位催化剂对苯酚的降解量略高于V-N-TiO_2。V-N-TiO_2/玻璃珠光催化复合材料既易于回收,又具有良好的光催化性能。     

Photocatalytic degradation of benzene on zeolite-incorporated TiO2 film

Zeolite powder was incorporated into the TiO2 film. Their photoactivities were evaluated for the gas phase degradation of benzene. Seven zeolite samples were used in this study and each enhanced the photocatalytic degradation. Humidity in the gas sample increased the degradation, but suppressed the adsorption of benzene to the TiO2 film. It was noted that the photoactivity was inversely proportional to the silica/alumina ratio of zeolite, whereas adsorption increased with this ratio. It was suggested that the adsorption of water onto zeolite contributes to the enhancement of benzene degradation.     

Ag/TiO2光催化薄膜清除乙烯气体的研究

乙烯对果蔬的生长有积极的作用,它可以促进果蔬的成熟,使其变得香甜可口。但果蔬成熟后乙烯的存在又可以加速果蔬的熟化程度,使其变得脆弱、易腐烂。因此,清除乙烯将对果蔬保鲜产生积极的影响。本文采用溶胶一凝胶方法制备了TiO2及Ag／TiO2薄膜。利用气相色谱法通过在自制的反应器内进行检测清除乙烯的实验,比较了TiO2薄膜和Ag／TiO2薄膜的光催化清除乙烯性能。结果发现,TiO2薄膜有较好的光催化清除乙烯性能,掺杂适量的Ag后,Ag／TiO2薄膜有更好的清除乙烯性能。本文还用XRD、SEM对TiO2及Ag／TiO2薄膜的形貌、物相结构、颗粒尺寸进行了表征分析并对实验结果进行了讨论。     

具有可见光活性的TiO2薄膜的制备及光催化性能

运用磁控溅射技术在浸渍－提拉法制得的TiO2薄膜上溅射三氧化钨层得到光催化薄膜。采用SEM、XRD、AES、UV－vis漫反射光谱等方法表征催化剂薄膜的厚度、晶相结构、化学元素组成及光吸收性能。以甲基橙的光催化降解为反应模型，高压汞灯为光源，溅射有三氧化钨薄膜的光催化活性低于纯TiO2薄膜；滤过紫外光后，溅射有三化钨的薄膜光催化活性明显高于纯TiO2薄膜。本实验提供了一种制备高可见光活性的TiO2薄膜的方法。     

TiO2薄膜的制备及光催化性能研究

采用溶胶－凝胶法在玻璃衬底上制备了均匀透明牢固的TiO2光催化薄膜,利用XRD、SEM分光光度计及椭圆偏光测厚仪对薄膜进行了分析。利用光催化降解乙醛气体实验研究了TiO2薄膜的光催化活性。结果表明膜的特性及孔隙度同水解条件密切相关。孔隙度及薄膜厚度对催化活性有大的影响。     

TiO2纳米纤维的制备及其对染料的光催化降解性能

采用溶胶-凝胶与静电纺丝技术相结合的方法,将聚乙烯吡咯烷酮(PVP)和钛酸四正丁酯混合制得前驱体溶液,纺丝得PVP/TiO2复合纳米纤维,然后经500℃高温煅烧制备了TiO2纳米纤维光催化剂,通过其对阳离子艳红5GN、弱酸性黄GN、雷马素蓝RR等染料的降解研究了TiO2纳米纤维的光催化性能。利用扫描电子显微镜(SEM)观察了PVP/TiO2和TiO2纳米纤维的形貌结构;傅里叶变换红外光谱(FT-IR)证实了TiO2纳米纤维的形成;通过X射线衍射仪(XRD)对TiO2纳米纤维的晶型及晶粒大小进行了分析。结果表明制备出的TiO2纳米纤维形貌稳定,具有锐钛矿型TiO2结晶形态并对染料具有很好的光催化降解效果。     

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.     

纳米TiO2固相光催化降解PVC糊薄膜的研究

以纳米TiO2为光催化剂,以ATBC为增塑剂,制备了纳米-TiO2/PVC糊复合膜。研究了该薄膜在紫外光照射条件下的降解性能,并进行了GPC、SEM、FT-IR等分析,测试了复合膜经紫外光照射前后的质量变化、分子量变化、表面形貌的变化。结果表明,该复合膜在紫外光照射下,降解速率可提高128.43%左右。GPC测试结果表明,经紫外光照射720h后,数均分子量Mn和重均分子量Mw可分别降低24.75%和17.7%左右;SEM表明,降解后PVC糊复合膜表面有大量裂纹且部分裂解成碎片。     

非晶态TiO2-Ag薄膜的光催化性能研究

采用磁控溅射技术在玻璃基片上制备了非晶态的TiO2-Ag薄膜,用XRD、XPS、STS和椭圆偏光测厚仪等对薄膜的晶体结构、表面成分、电子结构和薄膜厚度进行了测试分析.试验和测试结果表明,薄膜呈非晶态,在薄膜表面存在单质Ag,其与Ti的原子浓度比为1.8:1.STS测试得到薄膜的禁带宽度为1.8eV.对10mg/L的亚甲基蓝溶液光催化脱色实验表明,随着薄膜厚度的增加,光催化脱色率递增,当厚度达360nm时,薄膜对亚甲基蓝的脱色率在2h达90%以上,当厚度＞360nm时,光催化脱色率不再增加;对2mg/L罗丹明B溶液光催化脱色实验表明,其脱色率对薄膜厚度的增加不敏感,薄膜对罗丹明B的脱色率在3h内达到88.7%.     

TiO_2-海藻酸钙复合膜的表征、对染料的光催化降解及TiO_2回收

为了解决TiO2纳米粒子难分离,负载的催化剂难回收等问题,首先,将TiO2与海藻酸钠充分混合制成铸膜液,在玻璃板上刮膜,经钙离子交联制备了TiO2-海藻酸钙(T-CA)复合膜。然后,对T-CA复合膜进行了SEM和XRD表征,并研究了T-CA复合膜对染料的光催化降解性能。最后,将T-CA复合膜从染料降解液中取出,浸泡在柠檬酸钠水溶液中,柠檬酸根对钙离子的结合力较强,可使海藻酸盐水凝胶溶解,离心分离TiO2纳米粒子并清洗干燥后,得到了回收TiO2;利用SEM、TEM、FTIR和XRD对回收TiO2进行了表征。结果表明:T-CA复合膜对甲基橙的光催化降解率可达82.37%。回收TiO2与初始的TiO2几乎完全一样,可重新使用且催化能力不变。该方法是一种绿色环保、方便快速的从载体中回收TiO2纳米粒子的方法。