可见光响应的LaVO4/TiO2 纳米管的合成、表征及对气相甲苯的光催化性能

通过水热方法合成了可见光响应的LaVO4/TiO2纳米管, 采用XRD, TEM, 氮气吸附-脱附以及表面光电压谱对样品进行了表征. 以气相甲苯为典型污染物, 研究了制备样品在可见光(λ＞420 nm)条件下的光催化性能. 实验结果表明, LaVO4的复合使TiO2的粒径减小, 比表面积增大, 光响应范围向可见光偏移. 光催化实验结果表明, 在可见光条件下, LaVO4/TiO2纳米管降解甲苯的效率比其它样品高, 与纯TiO2纳米管相比, 降解效率提高了47%.     

掺杂Cu的TiO2纳米粒子的制备、表征及其光催化活性

采用Sol-gel法制备了纯的和掺杂不同量Cu的TiO2纳米粒子,并用TG-DTA,XRD,XPS,UV-Vis和荧光光谱对样品进行了表征,考察焙烧温度和Cu含量对TiO2纳米粒子的性质及光催化活性的影响,初步探讨了Cu的掺杂对TiO2相变的作用机制及样品荧光光谱与光催化活性的关系.结果表明,Cu2+的掺杂对TiO2的相变有很大的促进作用,并使其光谱响应范围向可见光区拓展.Cu的掺杂未引起新的荧光现象,但适量Cu的掺杂能够降低TiO2纳米粒子的荧光强度.此外,在光催化降解苯酚的实验中,于500℃处理的掺杂Cu的TiO2纳米粒子的光催化活性较高,与表征结果一致.而掺杂不同量Cu的TiO2的光催化活性顺序与样品荧光光谱强度的顺序相反,即荧光光谱强度越低,其光催化活性越高.     

CeO_2/ZnO复合纳米管的制备及其光催化性能的研究

用纳米CeO2掺入ZnO纳米管制备了CeO2/ZnO复合纳米管,考察了复合纳米管的光学及其光催化性能,并运用X射线衍射、透射电镜、比表面积测定和紫外-可见漫反射光谱等技术对样品进行了表征.结果表明,与ZnO纳米管相比,CeO2/ZnO复合纳米管的比表面积虽有所降低,但光催化活性有所提高,随着复合纳米CeO2量的增加,催化剂的光催化活性相应降低,太阳光下CeO2/ZnO复合纳米管对甲基橙溶液也有较高的催化活性.     

碳掺杂的二氧化钛纳米管的制备及其可见光催化性能

以尿素作为碳元素前驱体对TiO2纳米管进行掺杂,采用比表面积测定、X射线衍射、透射电子显微镜、能量色散X射线荧光光谱、X射线光电子能谱、固体漫反射紫外-可见吸收光谱和荧光光谱对产物进行了表征。 结果表明,以尿素作为前驱体可制备C掺杂的TiO2纳米管,C掺杂后,TiO2纳米管的可见光催化活性明显提高。 此外,研究了C掺杂量、煅烧温度、催化剂用量和pH值对TiO2纳米管光催化降解活性的影响,发现当C的掺杂量为5.3%、催化剂用量为1.5 g/L、溶液的pH值为5时,在其催化作用下,可见光光照3 h后罗丹明B的降解率可达到91%。     

TiO2/LaFeO3微纳米纤维的可控制备及光催化性能简

利用静电纺丝技术及水热合成法制备了TiO2/LaFeO3异质结构. 采用场发射扫描电子显微镜(FE-SEM),X射线衍射(XRD),傅里叶变换红外(FTIR)光谱和紫外-可见漫反射光谱(UV-Vis)等手段对TiO2/LaFeO3微纳米纤维的结构和表面形态进行表征. 通过亚甲基蓝(MB)光降解反应研究了其光催化性能. 结果表明,不完全碳化TiO2纤维表面的缺陷位点是LaFeO3纳米粒子的有利生长点. TiO2/LaFeO3异质结材料的带隙明显窄于TiO2,光催化活性得到提高;经140 min紫外光照射后,TiO2/LaFeO3异质结催化剂对MB的降解率为65.34%,分析和探讨了其光催化机理.     

Fe3+-TiO2/SiO2光催化降解罗丹明B的研究

以硅胶为载体,采用溶胶-凝胶法制备了不同掺杂量的Fe3+-TiO2/SiO2光催化剂,并采用SEM,Raman和DRS等手段对其进行了分析和表征.以氙灯为光源,通过对可溶性染料罗丹明B的降解反应,考察了Fe3+-TiO2/SiO2催化剂的光催化活性,探讨了光催化反应中溶液pH值和起始浓度对催化反应的影响.     

ZnO和TiO2纳米粒子的光致发光性能及其与光催化活性的关系

采用沉淀法和溶胶-凝胶法制备了ZnO和TiO2及掺Zn2+的TiO2纳米粒子,用XRD和荧光光谱(FS)等手段对样品进行了表征,重点探讨了样品光致发光机制及与光催化活性的关系.结果表明,ZnO和TiO2样品在大于带隙能的光激发下均表现出明显的FS信号,热处理温度升高,FS信号强度下降,并且二者的FS信号类似,这可能与二者具有类似的电子能带结构有关,同时也说明FS信号主要源于表面氧空位以及吸附氧物种等引起的激子或表面态能级.掺杂Zn2+使TiO2纳米粒子FS信号增强,这主要与表面氧空位和缺陷等量增加有关;此外,在光催化氧化苯酚实验中,样品光催化活性与其FS信号强度顺序一致,即FS信号越强,活性越高.这是由于在光致发光过程中,FS信号主要源于表面氧空位,而在光催化反应中,表面氧空位有利于氧化反应进行.     

TiO_2光催化失活复活特性与表面NO_3~-浓度的关系

以乙醛作为活性标的,通过人为控制表面附着NO3-浓度,检测TiO2对乙醛的吸附能力和光催化降解能力,得出了TiO2光催化失活复活特性和表面附着NO3-浓度的定量关系。结果表明,表面附着NO3-浓度达到4.24wt%时,光催化降解能力降低50%;表面附着NO3-浓度达到10.50wt%时,TiO2的吸附能力降低50%;通过溢流状态下水洗2h,可除去98%的表面附着NO3-,使TiO2光催化活性复活。     

添加NaBF_4对阳极氧化法制备TiO_2纳米管光催化剂的影响

在阳极氧化电解液中添加Na BF4制得了具可见光活性的B掺杂TiO_2纳米管阵列(B/TNTs)。采用扫描电镜(FE-SEM)、能谱仪(EDS)、X射线衍射(XRD)、傅立叶红外光谱(FTIR)、紫外-可见漫反射光谱(UV-Vis DRS)以及X射线光电子能谱(XPS)对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应评价其光催化活性。结果表明:添加Na BF4后,TiO_2纳米管表面形貌变化较大;B掺入到TiO_2晶格中形成B-O-Ti键;B掺杂使得TiO_2纳米管表面羟基量增加、光学带隙能减小、光吸收阀值红移,且B掺杂量越多,其相应值的变化量越大;B掺杂能促进TiO_2锐钛矿相的发育,纳米管经550℃煅烧后仍保持未掺杂样品的锐钛矿相结构;Na BF4的最佳添加量为0.6%(w/w)时,所得样品光催化活性最佳,可见光下光催化降解MB的4 h降解率由未添加的39.90%提高至75.15%,且反复使用10次后其光催化性能基本保持不变;总有机碳(TOC)分析结果表明,MB在可见光下能被B/TiO_2有效矿化。     

TiO2纳米薄片的合成及其光催化降解苯酚性能

以钛酸纳米管为前驱体,通过添加NaF高温水热合成了(001)面暴露的TiO₂纳米薄片,并对其催化苯酚光降解行为进行了研究。结果表明经水热反应后,钛酸型TiO₂纳米管(NT)转晶成锐钛矿型TiO₂纳米薄片(NS),且具有高(001)暴露面。和NT相比,NS对苯酚的光催化降解活性显著提高,其活性随水热温度升高而增加。NS光催化去除苯酚符合一级动力学,其中200 ℃合成的NS反应速率常数k最高,为0.083 min^-1。同时,苯酚的光催化反应初活性与其初浓度的关系符合Langmuir-Hinshelwood模型,表明苯酚的光催化降解受吸附控制。     

超声波-二氧化钛光催化耦合法降解高效氯氰菊酯

采用超声波-TiO2光催化耦合法降解高效氯氰菊酯,考察了高效氯氰菊酯初始浓度、降解时间、溶液pH、催化剂用量等对高效氯氰菊酯农药残留的降解效果,并利用水果进行了实物模拟.结果表明:利用超声波-TiO2光催化耦合法能够有效地降解高效氯氰菊酯农药残留.在弱酸环境中,当纳米TiO2投放量为1.2g/L时,经2h超声催化降解,不同浓度的高效氯氰菊酯农药稀释液均被有效降解,降解率最高可达98.3%.     

Effect of Binder on the Structure and Properties of Silicon Powder-supported TiO_2 Photocatalysis Material

Recoverable TiO2 photocatalysis material supported by silicon powder was prepared with sol-gel method, afterwards the silica gol and sodium silicate were used as molding binder respectively to investigate their effects （including binder type and binder addition quantity） on the crystal structure and catalysis properties of photocatalyst. In this work, the catalysis activity was defined as the degradation rate of methyl orange solution upon ultraviolet lamp irradiation, and the specific areas were determined with nitrogen desorption method. TiO2 crystal form was measured with X-ray powder diffraction and their micro-morphology was observed with SEM. Experimental results indicate that these two binders do not affect the crystal form transformation of TiO2, but silica gol can increase the specific surface area of TiO2 photocatalyst obviously and the addition of sodium silicate can decrease it. In all, silica gol is a better candidate than sodium silicate for higher catalysis property. In conclusion, 6% silica gol is the optimal addition concentration. Under this condition, the ratio of anatase to rutile TiO2 is 64：36, the specific area is 29.67 m^2/g, and as expected, the degradation rate of methyl orange could be as high as 90% after irradiation for 5 days.     

Fe2O3/TiO2纳米管的制备及其光电催化降解染料废水性能

采用阴极电沉积和阳极氧化法制备了Fe2O3改性TiO2纳米管(Fe2O3/TiO2-NTs)电极,运用场发射扫描电子显微镜、透射电子显微镜、X射线衍射和紫外-可见漫反射光谱等手段对其进行了表征,考察了其光电化学性能,并研究了复合电极光电催化降解甲基橙染料废水的反应性能.结果表明,Fe2O3的负载成功地将TiO2-NTs的光响应区间拓宽到可见光区域,Fe2O3/TiO2-NTs复合电极的光电流密度达到TiO2-NTs电极的3倍.在光电催化反应中,Fe2O3/TiO2-NTs复合电极对甲基橙的脱色效果明显优于TiO2-NTs电极,以Fe2O3/TiO2-NTs为阳极,光照5min,甲基橙溶液的脱色率可达90%以上.     

二氧化钛光催化降解有机磷农药的机理和影响因素

综述了反应液起始pH值、TiO_2用量、空气流量、Fe~(3+)浓度、有机磷农药结构、不同元素掺杂TiO_2、载体等因素对TiO2光催化降解有机磷农药降解率的影响。     

Process optimization and kinetics study for photocatalytic ciprofloxacin degradation using TiO2 nanoparticle: A comparative study of Artificial Neural Network and Surface Response Methodology

The photocatalytic degradation of ciprofloxacin was investigated by developing a predictive mathematical model using response surface methodology and an artificial neural network. The four independent variables involve solution pH, reaction time, catalyst dose, and initial antibiotic concentration considered as factors in central composite design to observe the response in the form of antibiotic degradation. Accordingly, at an optimum antibiotic concentration of 5.02 mg/L, catalyst dose of 44.51 mg/L, solution pH of 5.04, and reaction time of 75.80 min, the photocatalysis method achieved a ciprofloxacin degradation of 88.30%. The experimental outputs were very much consistent along with the predicted output of experiments through response surface methodology (R² = 0.9969) and artificial neural network (R² = 0.975). The adsorption isotherm and kinetic study reveal that Langmuir isotherm and pseudo-second-order kinetic models respectively were best fitted for degradation of ciprofloxacin through photocatalysis. The finding provides a novel method for evaluating the photocatalysis process for the optimization of ciprofloxacin antibiotic removal from pharmaceutical waste using experiments and computer simulation tools.     

Template Synthesis and Characterization of Cu2O/TiO2 Coaxial Nanocable for Photocatalysis

Coaxial nanocable consisted of p-type Cu₂O nanowires and n-type TiO₂ nanotubes arrays was prepared in the porous anodic aluminum oxide(AAO) template via the sol-gel method and subsequent electrodeposition method. X-ray diffraction analysis identified an anatase structure of the TiO₂ nanotubes and cubic structure of the Cu₂O nanowires. The obtained samples were also characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM) and energy dispersive X-ray spectroscopy(EDS). The diffrence of open circuit potential of the coaxial nanocable electrode was larger than that of the TiO₂ nanotubes electrode under ultraviolet illumination, which means doping with Cu₂O could improve the photovoltage effectively. Meanwhile, nanocable arrays exhibited a high activity for photodegrading Rhodamine B under Xe lamp irradiation and the photocatalysis degradation efficiency was up to 98.69% after degradation for 7 h. The enhanced photocatalytic activity could be attributed to the high migration efficiency of photoinduced electrons, which may suppress the charge recombination effectively.     

无氧条件下Pt/TiO2光催化重整降解一乙醇胺水溶液制氢

以一乙醇胺（以下简称乙醇胺）为电子给体,在无氧条件下进行了Pt/TiO2光催化重整制氢的研究.详细讨论了诸多因素如催化剂表面Pt化学状态、Pt担载量、溶液pH值、乙醇胺溶液浓度等对产氢效率的影响,并用XRD、HNMR、XPS等进行了深入表征,探讨了Pt/TiO2光催化重整降解乙醇胺和产氢的反应, 实验表明,利用所制备的光催化剂, 可实现在消除水中有机污染物的同时制取氢气的目标.催化剂表面的Pt以Pt0的化学状态存在, 有利于析氢;溶液pH值和浓度的变化对产生速率也有一定的影响.同时发现Pt/TiO2光催化重整乙醇胺制氢反应的最佳条件是:Pt的最佳担载量约为0.5％～1.0％;乙醇胺溶液最佳浓度约为0.05 mol•L－1;最佳溶液pH值范围为4～10;氨基取代的羰基类化合物是其主要中间产物.     

Synthesis and characterization of ultrahigh crystalline TiO2 nanotubes

Ultrahigh crystalline TiO2 nanotubes were synthesized by hydrogen peroxide treatment of very low crystalline titania nanotubes (TiNT-as prepared), which were prepared with synthesized TiO2 nanoparticles by hydrothermal methods in an aqueous NaOH solution. Thus, prepared ultrahigh crystalline TiO2 nanotubes (TiNT-H2O2) showed comparable crystallinity with high crystalline TiO2 nanoparticles. The details of nanotubular structures were elucidated by high resolution-transmission electron microscopy (HR-TEM), field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis in transmission electron microscopy (TEM-EDX), X-ray diffraction (XRD), photoluminescence (PL), and BET surface area. TiNT-H2O2 was found to be a multiwalled anatase phase only with an average outer diameter of approximately 8 nm and an inner diameter of approximately 5 nm and grown along the [001] direction to 500-700 nm long with an interlayer fringe distance of ca. 0.78 nm. The photocatalytic activity of TiNT-H2O2 was about 2-fold higher than those of TiNT-as prepared, synthesized TiO2 nanoparticles, and TiO2-P25 (Degussa) in the photocatalytic oxidation of trimethylamine gas under UV irradiation.     

纳米二氧化钛负载棉织物的制备及性能

以棉织物为基体,通过紫外辐照和超声法将不同表面性质的TiO_2纳米粒子负载到棉织物上,制备自清洁材料.利用扫描电子显微镜、能谱分析、接触角、紫外-可见光谱及降解甲基橙溶液等手段分别对样品表面的结构形貌、元素分布、光催化活性、紫外屏蔽性能和耐久性等进行分析.结果表明,棉织物经紫外辐照后,TiO_2纳米粒子与其结合更牢固,耐久性更佳;TiO_2负载后的棉织物表现出超疏水性能及优异的光催化活性和紫外屏蔽性能;与未改性的TiO_2纳米粒子相比,由聚乙烯醇(PVA)改性的TiO_2纳米粒子制备的自清洁棉织物的可见光光催化活性更高,其可见光的光催化效率是前者的3.9倍.PVA改性的纳米TiO_2对290~400 nm范围内的紫外光有较好的吸收作用,其紫外屏蔽效果更佳.