多种光源下氮掺杂TiO_2光催化降解染料废水的研究

以尿素为氮源,采用溶胶-凝胶法制备了氮掺杂纳米TiO2粉末,以甲基橙溶液为模拟染料废水,分别在可见光、模拟太阳光和紫外光条件下,研究了氮掺杂纳米TiO2光催化降解染料废水的性能。结果表明:氮掺杂可以提高TiO2的可见光催化活性;氮含量和煅烧温度对氮掺杂TiO2光催化活性影响较大,n(N)∶n(Ti)为10%且经500℃煅烧的氮掺杂TiO2在可见光和模拟太阳光下均具有最佳的光催化活性;然而在紫外光下,氮掺杂TiO2的光催化活性低于未掺杂的TiO2样品。     

氮掺杂纳米二氧化钛的制备及其光催化性能

以三乙醇胺为氮源采用水热法制备了氮掺杂纳米TiO2光催化剂,采用XRD、TEM和UV—vis／DRS分析、表征氮掺杂对TiO2微晶尺寸、晶体结构、表面组成与光学性能的影响,并通过降解甲基橙溶液研究其光催化活性。结果表明：制得的氮掺杂二氧化钛均为锐钛矿型,粒径约为10nm,a掺杂引起光催化剂的吸收波长向可见光区红移。当pH=11．0,300℃焙烧3h时制得的氮掺杂TiO2光催化活性最强,甲基橙50min的降解率达98％。     

钕和镨共掺杂TiO2光催化性能的研究

采用溶胶-凝胶法制备纯纳米TiO2、钕和镨掺杂的纳米TiO2光催化剂,以甲基橙为目标降解物,研究了催化剂加入量、染料初始质量浓度、溶液pH值对甲基橙降解率的影响。实验结果表明,钕掺杂的纳米TiO2光催化活性高于纯纳米TiO2的光催化活性,而适量钕镨共掺杂纳米TiO2光催化活性可进一步提高,最佳掺杂浓度为0．5％的钕和0．2％的镨。当钕和镨共掺杂纳米TiO2催化剂加入量为2．0g／L,甲基橙溶液的初始质量浓度为30mg／L,pH值为10．5时,在40w紫外灯光照射35min后降解率最好,可达到93％。     

薄膜化固体超强酸SO4^2-／TiO2-WO3光催化降解甲基橙

采用硫酸溶液漫渍处理TiO2—WO3制得SO4^2-／TiO2-WO3薄膜光催化剂,考察了光催化荆对甲基橙溶液的光催化降解行为。结果表明,在硫酸浓度为0．2mol·L-1、焙烧温度为550℃、WO3掺杂量为2％的最佳条件下制备的光催化剂活性最高,甲基橙降解90min的降解率达到72％。     

Fe^3＋掺杂纳米TiO2光催化剂的制备及其光催化性能研究

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,正丁醇为助表面活性剂,环己烷为油相,采用微乳液法制备出Fe3+掺杂纳米TiO2,用X-射线衍射(XRD)对纳米TiO2粒径、物相等方面进行了表征.通过光催化降解甲基橙溶液考察了TiO2的光催化性能.甲基橙降解实验结果表明,溶液的pH=2时降解率可达100%;掺杂Fe3+会影响TiO2光催化性能,n(Ti4+):n(Fe3+)=1:0.000 4的TiO2在前10 min降解率高达54.50%,60 min降解率可达93.33%,掺杂浓度增大到一定程度后,降解率反而下降,说明存在较佳掺杂浓度.另外,溶液初始浓度对TiO2光催化性能有一定的影响.     

钕和镨共掺杂TiO2光催化性能的研究

采用溶胶—凝胶法制备纯纳米TiO2、钕和镨掺杂的纳米TiO2光催化剂,以甲基橙为目标降解物,研究了催化剂加入量、染料初始质量浓度、溶液pH值对甲基橙降解率的影响.实验结果表明,钕掺杂的纳米TiO2光催化活性高于纯纳米TiO2的光催化活性,而适量钕镨共掺杂纳米TiO2光催化活性可进一步提高,最佳掺杂浓度为0.5％的钕和0.2％的镨.当钕和镨共掺杂纳米TiO2催化剂加入量为2.0g/L,甲基橙溶液的初始质量浓度为30 mg/L,pH值为10.5时,在40 W紫外灯光照射35 min后降解率最好,可达到93％.     

Ni、B共掺杂TiO2-陶粒光催化降解染料废水研究

采用溶胶一凝胶法制备陶粒负载Ni2O3和B元素共掺杂纳米TiO2可见光催化剂,以甲基橙为目标降解物,探讨了光催化氧化降解甲基橙的规律,考察了催化剂的焙烧温度、Ni元素和B元素掺杂量、催化荆投加量、甲基橙溶液初始浓度、初始pH值、反应温度等因素对甲基橙脱色效果的影响。结果表明：在600℃温度下焙烧的催化剂具有最佳光催化活性;B和Ni最佳掺杂量为3．0％;甲基橙脱色率随甲基橙初始浓度的降低、催化剂投加量的增加、反应温度的升高、初始pH值降低而增大;催化剂经重复使用后,仍具有较高的光催化性能。     

掺杂铁TiO2纳米微粒的制备及光催化性能

以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备了Fe^3＋掺杂改性纳米TiO2光催化剂,通过纯TiO2和掺铁TiO2分别做光催化荆时甲基橙溶液在紫外光下的光催化降解试验发现,掺杂铁离子可以有效提高TiO2的光催化活性,结果表明：选用Fe^3＋掺杂量为0．05％,煅烧温度在500℃下得到的Fe^3＋．TiO2催化剂,在甲基橙溶液pH值为3,催化剂投加量为1g／L时,其光催化活性达到最佳效果。     

薄膜化固体超强酸SO2-4/TiO2-WO3光催化降解甲基橙

采用硫酸溶液浸渍处理TiO2-WO3制得SO42-/TiO2-WO3薄膜光催化剂,考察了光催化剂对甲基橙溶液的光催化降解行为.结果表明,在硫酸浓度为0.2 mol·L-1、焙烧温度为550℃、WO3掺杂量为2％的最佳条件下制备的光催化剂活性最高,甲基橙降解90 min的降解率达到72％.     

氮掺杂花状黑色二氧化钛(TiO_2)的制备及光催化性能研究

本论文以金属钛粉和尿素为原料,利用水热法制备出氮掺杂黑色二氧化钛(TiO_2)光催化剂,并对其光催化性能进行了红外光谱、紫外光谱和SEM等表征实验,探讨了氮掺杂花状黑色二氧化钛(TiO_2)光催化剂的光催化性能。将甲基橙溶液作为目标降解染料,在模拟太阳光条件下照射含有不同氮掺杂含量的光催化剂的甲基橙溶液,紫外—可见分光光度计测试不同光催化剂的光催化性能。通过对不同形貌,不同掺杂量的催化剂比较研究,探讨结构与光催化性能之间的关系。实验结果表明:以尿素:黑色花状二氧化钛=2:1的比例制备的氮掺杂花状黑色二氧化钛催化剂对甲基橙溶液的催化降解效果最好,提高了对染料的降解作用。     

晶相结构对二氧化钛氮掺杂类型及其光催化性能的影响

采用沉淀法制备不同晶型的TiO_2,采用微波法和氨气气氛焙烧法制备了氮掺杂纳米TiO_2,对其进行了XRD、XPS和UV-Vis表征,通过光催化性能的评价,考察晶型对氮掺杂TiO_2光催化活性的影响。结果表明,在TiO_2掺氮过程中,间隙氮与取代氮形式主要由制备方法决定,并不随晶型不同而变化。两种方法掺氮后对锐钛矿和金红石结构TiO_2的可见光光催化活性均有较大提高,但复合相结构的可见光光催化活性没有明显提高。     

氮掺杂TiO_2水热法制备及其光催化活性的研究

以钛酸四丁酯、尿素、无水乙醇为原料,采用水热合成方法制备了掺氮和不掺氮的二氧化钛前驱体。以250W高压汞灯为光源,达旦黄水溶液为活性评价体系,设计正交表研究了N-TiO2光催化实验的最佳条件。研究了N-TiO2对不同拟污染物的降解能力,分析了可见光条件下N-TiO2和TiO2光催化活性。     

Study on the visible-light-induced photokilling effect of nitrogen-doped TiO2 nanoparticles on cancer cells

Nitrogen-doped TiO2 (N-TiO2) nanoparticles were prepared by calcining the anatase TiO2 nanoparticles under ammonia atmosphere. The N-TiO2 showed higher absorbance in the visible region than the pure TiO2. The cytotoxicity and visible-light-induced phototoxicity of the pure- and N-TiO2 were examined for three types of cancer cell lines. No significant cytotoxicity was detected. However, the visible-light-induced photokilling effects on cells were observed. The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles. The cancer cells incubated with N-TiO2 were killed more effectively than that with the pure TiO2. The reactive oxygen species was found to play an important role on the photokilling effect for cells. Furthermore, the intracellular distributions of N-TiO2 nanoparticles were examined by laser scanning confocal microscopy. The co-localization of N-TiO2 nanoparticles with nuclei or Golgi complexes was observed. The aberrant nuclear morphologies such as micronuclei were detected after the N-TiO2-treated cells were irradiated by the visible light.     

制备条件对柴油车用V2O5-WO3/TiO2催化剂催化性能的影响

采用偏NH4VO3和TiO2为前驱体制备选择性催化还原(SCR)催化剂涂层所需浆料,分别以分步涂覆法和一步涂覆法将浆料浸涂在蜂窝陶瓷载体上,得到了整体涂覆式选择性催化还原催化剂.对草酸添加量、焙烧时间及V2O5含量对催化活性的影响进行了研究,结果表明,V2O5(4%)-WO3/TiO2(450℃,3 h)和V2O5(5...     

Enhanced visible-light-driven photocatalysis of surface nitrided electrospun TiO2 nanofibers

Enhanced visible-light-driven photocatalysis of TiO(2) nanofibers have been prepared by the electrospinning method combined with a surface nitridation process. The visible-light-driven photo-catalytic activity of surface nitrided TiO(2) (N-TiO(2)) nanofibers has been evaluated using rhodamine B indicator, and it was found that the visible-light-driven photocatalytic activity of the electrospun TiO(2) nanofibers could be enhanced by nitridation in NH(3) atmosphere. The optimal visible-light photocatalytic activity of N-TiO(2) nanofibers exceeded that of pure TiO(2) nanofibers by a factor of more than 12. The nitridation temperature under NH(3) flow was found to play an important part in the performance of N-TiO(2) nanofibers, and the optimum temperature is 500 °C. Structure, morphology and photoluminescence of these nanofibers were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and photoluminescence (PL) spectroscopy. The mechanism of the enhancement of visible-light-driven photocatalytic activity by surface nitridation has been discussed.     

N-TiO2/Ti3C2复合材料的原位合成及其光催化性能

以钛碳化铝、氢氟酸、氟硼酸钠为原料，以尿素为氮源，通过简单的溶剂热反应，在高导电性的Ti3C2 MXenes（二维过渡金属碳化物）纳米片上原位生长氮元素掺杂的TiO2纳米片，合成了二维N-TiO2/Ti3C2光催化复合材料。采用X射线衍射仪、扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、紫外-可见漫反射光谱仪、光致发光光谱仪等对催化剂样品进行了结构表征。结果表明，在可见光照射下，N-TiO2/Ti3C2复合材料对罗丹明B（RhB）表现出较好的光催化降解性能，其降解速率是纯TiO2的8.41倍，在150min内，罗丹明B降解率达到96.3%。这主要是由于氮元素的掺杂缩小了TiO2的带隙，将光响应范围扩展到可见光区域。同时，TiO2纳米片的原位生长使其与具有优异电导率的Ti3C2 MXenes纳米片形成了紧密的接触界面，促进了光生载流子的分离和迁移。自由基捕获实验和电子自旋共振测试结果显示，•O2-和•OH是N-TiO2/Ti3C2光催化体系降解罗丹明B的主要活性物种。此外，N-TiO2/Ti3C2复合材料具有良好的稳定性和可重复利用性。     

N-TiO_2/RGO复合光催化剂的制备及其性能

用改进的Hummers法制得了氧化石墨烯,以Ti（SO4）2为钛源,氨水为氮源,在400℃煅烧下制备了锐钛矿型的氮元素掺杂的TiO2（N-TiO2）。利用溶液混合法将二者混合,再经水热处理法制备了不同质量复合比例的N-TiO2/RGO光催化剂。通过X射线衍射、Fourier变换红外光谱、扫描电子显微镜等对样品的组成与形貌进行了表征,并通过降解1×10–4mol/L亚甲基蓝溶液表征了各样品的光催化效率。结果表明：掺杂氮元素一定程度上提高了TiO2的光催化效能,与石墨烯的复合更进一步改善了N-TiO2光催化效能。     

液体中铈掺杂TiO2光催化剂的制备及微波强化光催化活性

室温下,在离子液体［Bmim］PF₆中,采用溶胶-凝胶法及微波辐射干法制备了铈掺杂纳米TiO₂光催化剂TiO₂-Ce,并测试了TiO₂-Ce对甲基橙溶液的微波、紫外和微波-紫外条件下的降解率。着重考察了离子液体用量、微波干燥功率、微波干燥时间、焙烧温度、焙烧时间和铈掺杂量等因素对TiO2-Ce催化活性的影响。结果表明,离子液体用量5.6 mL,掺杂硝酸铈与钛酸丁酯物质的量比n(Ce)∶n(Ti)=0.075,功率210 W的微波条件下干燥20 min,高温箱式电阻炉550 ℃焙烧2.0 h,制得的TiO₂-Ce催化剂具有较高的光催化活性。在微波、紫外和微波-紫外降解条件下,TiO₂-Ce对甲基橙降解率分别为4.78%、93.82%和99.12%。表明在紫外光照条件下,微波辅射具有强化TiO₂-Ce催化剂降解甲基橙的作用。同时用XRD、IR、BET和SEM对TiO₂-Ce催化剂结构进行表征,结构分析表明,TiO₂中掺入铈后制得的催化剂具有粒径均匀以及半孔宽(2.485 2 nm)、孔容(0.314 5 mL·g^-1)、平均孔径(6.627 nm)和比表面积（94.934 m²·g^-1）均较大等特点,这也是TiO₂-Ce催化剂拥有较高的光催化活性的主要原因。     

黏结剂对柴油车用V_2O_5-WO_3/TiO_2催化剂选择性催化还原性能的影响

采用偏NH_4VO_3和TiO_2为前驱体制备选择性催化还原(SCR)催化剂涂层所需浆料,将浆料浸涂在蜂窝陶瓷载体上,得到整体涂覆式SCR催化剂。研究了SiO_2溶胶、H_3PO_4及H_3NO_3对催化剂涂层耐久性及活性的影响。在模拟评价装置上对催化剂活性进行了评价。结果表明,SiO_2溶胶和H_3PO_4对催化剂涂层耐久性具有明显改善作用,质量分数8%的SiO_2溶胶和4%的H_3PO_4使催化剂涂层脱落率从32.71%降至4.08%和17.89%;V_2O_5-WO_3/TiO_2-4%SiO_2溶胶催化剂表现出较高的活性和选择性,新鲜催化剂NO的起燃温度(T_(50))为205℃,随着H_3PO_4添加量的增加,催化剂低温活性逐渐降低,高H_3PO_4添加量时,催化剂表面被H_3PO_4覆盖,大部分与钛及钒键连接的羟基基团被P—OH所取代,催化剂SCR活性降低。     

One-step hydrothermal synthesis of N-doped TiO2/C nanocomposites with high visible light photocatalytic activity

N-doped TiO(2) nanoparticles modified with carbon (denoted N-TiO(2)/C) were successfully prepared by a facile one-pot hydrothermal treatment in the presence of L-lysine, which acts as a ligand to control the nanocrystal growth and as a source of nitrogen and carbon. As-prepared nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) spectra, and N(2) adsorption-desorption analysis. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methyl orange (MO) under visible light irradiation at λ≥ 400 nm. The results show that N-TiO(2)/C nanocomposites increase absorption in the visible light region and exhibit a higher photocatalytic activity than pure TiO(2), commercial P25 and previously reported N-doped TiO(2) photocatalysts. We have demonstrated that the nitrogen was doped into the lattice and the carbon species were modified on the surface of the photocatalysts. N-doping narrows the band gap and C-modification enhances the visible light harvesting and accelerates the separation of the photo-generated electrons and holes. As a consequence, the photocatalytic activity is significantly improved. The molar ratio of L-lysine/TiCl(4) and the pH of the hydrothermal reaction solution are important factors affecting the photocatalytic activity of the N-TiO(2)/C; the optimum molar ratio of L-lysine/TiCl(4) is 8 and the optimum pH is ca. 4, at which the catalyst exhibits the highest reactivity. Our findings demonstrate that the as-obtained N-TiO(2)/C photocatalyst is a better and more promising candidate than well studied N-doped TiO(2) alternatives as visible light photocatalysts for potential applications in environmental purification.