Preparation and characterization of aligned carbon nanotubes coated with titania nanoparticles

Titania (TiO2) is an environmental-friendly photo- catalyst material with high stability and efficiency, so its preparation methods received extensive atten- tion[1―4], and the products were advanced from dis- persed nano-powder and fastness nano-film[5,…     

硫氮共掺杂TiO2薄膜的可见光催化性能

以钛酸丁酯(C16H36O4Ti)和硫脲(SC(NH2)2)为前驱体制备溶胶,通过旋涂方法制备Ti O2光催化剂薄膜;利用XRD、SEM、XPS、UV-vis等手段进行结构表征和光吸收性能测试,并通过降解亚甲基蓝溶液评定其可见光下的光催化活性。结果表明,以硫脲为前驱体时可实现硫氮元素在Ti O2中的共掺杂;掺杂后的Ti O2薄膜对可见光有明显的吸收,并在可见光下对亚甲基蓝溶液显示出较高的降解率,其中掺杂量质量分数为3.0%的薄膜样品光催化活性最好。在本实验条件下,经可见光照射7 h后,亚甲基蓝溶液降解率接近100%。分析表明,硫元素以S6+状态取代Ti4+存在于Ti O2晶格,氮元素则以间隙和取代的方式存在。硫氮元素的协同作用在Ti O2的禁带中引入杂质新能级,使Ti O2带隙变窄,因此对可见光吸收并显示出强的可见光催化活性。     

煅烧温度对TiO_2粉体的微观结构及光催化特性的影响

以钛酸丁酯为原料,采用溶胶-凝胶法制备TiO2粉体。利用X射线衍射谱、拉曼光谱、红外光谱、扫描电子显微镜和紫外-可见光分光光度计分别研究煅烧温度对TiO2粉体的微观结构、颗粒形貌与紫外光光催化性能的影响。实验结果表明:随着煅烧温度的升高,TiO2粉体发生了锐钛矿到金红石结构的相变,相变温度大约在623K~673K,且等轴状颗粒的尺寸逐渐增加。同时发现锐钛矿结构的TiO2粉体对甲基橙的紫外光光催化活性最高,而无定形及金红石结构不利于粉体的紫外光光催化活性。     

Ni2+掺杂TiO2薄膜微观结构及亲水性能

采用溶胶-凝胶法结合浸渍-提拉技术制备Ni2+掺杂TiO2薄膜。利用X线衍射(XRD)、原子力显微镜(AFM)、X线光电子能谱(XPS)、紫外-可见吸收光谱(UV-vis)和接触角测试等表征手段,研究Ni2+不同掺杂量对TiO2薄膜的晶型结构、化学组成、氧化态及光学和亲水性能的影响。研究结果表明:Ni2+掺杂TiO2的晶相主要为锐钛矿,随着Ni2+掺杂量的增加,TiO2晶格发生一定的畸变,掺杂TiO2薄膜的吸收边向可见光范围产生不同程度的红移,与水的接触角逐渐减小。10%Ni2+掺杂TiO2薄膜的接触角仅为12°,表现出良好的润湿性,将在新型自洁净建筑材料具有广阔的应用前景。     

多价硫掺杂二氧化钛的制备及可见光催化性能

采用低温水热法制备了多价硫(S4+/S0)掺杂的二氧化钛催化剂(S-TiO2),运用低温氮吸附、X射线粉末衍射、紫外可见漫反射光谱和X射线光电子能谱等技术对催化剂进行了表征,并以可见光催化降解丙酮作为模型反应考察其可见光催化活性.结果表明,与TiO2相比,S-TiO2催化剂的BET比表面积大、孔径分布集中、光谱吸收边红移、锐钛矿向金红石的相转化被抑制,具有较高的可见光催化活性.     

不同退火温度镍注入二氧化钛的结构与磁性

为了证实铁磁性的来源,选用注入剂量相同、退火温度不同的镍注入二氧化钛的4种样品,用同步辐射X线衍射、卢瑟福背散射/沟道实验和超导量子干涉仪,对样品分别进行了θ-2θ扫描、随机谱和沟道谱以及磁性的测试.结果表明:镍注入二氧化钛在高温退火后的结构发生了变化,形成了镍-纳米粒子,其嵌入二氧化钛中的镍-纳米粒子的结构和样品的磁性可以通过退火来调节.随着退火温度的增加,镍-纳米粒子的尺度增加,并且退火温度稳定在1 073 K以上;镍注入二氧化钛中能够测量到铁磁性,其主要原因是金属镍-纳米粒子的形成;另外,其他因素对二氧化钛铁磁性也有贡献,像辐照产生的缺陷、镍原子替位等.     

Synthesis,characterization,and theoretical study of N,S-codoped nano-TiO2 with photocatalytic activities

Nitrogen and sulfur doped titanium dioxide photocatalysts were prepared by the sol-gel method.The products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and UV-visible diffuse reflectance spectra (DRS).Photocatalytic activities of the samples were investigated on the degradation of methyl orange (MO).The effect of the dopants on the electronic structure of TiO2 was studied by the first-principles calculations based on the density functional theory (DFT).The orbital hybridization resulted in energy gap narrowing and electronic delocalization in the crystal of doped TiO2.Mobile electrons of varied energetic states could offer enhanced electron transfer,together with optical absorption improvement.The results show that the doping elements of N and S play a cooperative role in the modification of electronic structure,which enhances the photocatalytic performance.The experimentally observed absorption edges of N-doped TiO2,S-doped TiO2,and N,S-codoped TiO2 are 420,413,and 429 nm,respectively,which can be explained by the theoretical calculation results.     

热氧化法制备 TiO2薄膜电极及其光电流性能

采用热氧化钛片的方法制备了TiO2薄膜电极,然后利用X射线衍射（XRD）、扫描电子显微镜（SEM）、荧光光致发光（PL）、拉曼光谱（Raman）、光电流和光电压等实验技术进行表征,考察了不同热处理温度对薄膜的形貌、晶相结构、光学性质和光电流性能等的影响．结果表明：随着热处理温度由3000C提高到600℃,在钛片表面上逐步生成晶粒细小、多孔且荧光强度逐渐降低的纯金红石TiO2薄膜,并可获得分别为0．154mA／cm2和0．3V的最大阳极光电流和光电压,而继续增大热处理温度虽有助于氧化膜的形成,但光电流和光电压则急剧减小．因该热处理方法具有操作简单、生成的表面膜与基底的附着性好且光电性能稳定等特点,使其在TiO2膜电极制备方面有较好的应用前景．     

TiO2-Ag2O复合纳米纤维烟气脱汞实验研究

使用静电纺丝法制备TiO。及TiO2-Ag2O纳米纤维,脱除模拟烟气中的汞元素．对纳米纤维进行了XRD,SEM,EDX,uV—Vis及BET检测．研究了不同光照条件下Ag。O的掺杂比和循环次数对脱汞的影响,分析了TiO2-Ag2O的脱汞机理．结果表明：TiO2-Ag2O纳米纤维为锐钛矿相,纤维直径在200nm左右．与纯TiO2相比,TiO2-Ag2O的吸光范围增大,对可见光的利用率提高,并且随着AgzO掺杂量的增加纤维对光的吸收也逐渐增强．TiO2-Ag2O纳米纤维在无光、可见光及紫外光下的脱汞率均达到95％以上．合成的复合纳米纤维脱汞性能稳定,到第8次循环时脱汞率仍保持在95％以上．TiO2—Ag2O脱汞的机理可为银与汞通过汞齐化作用形成银汞合金．     

硬脂酸凝胶法制备TiO_2纳米粉末及其表征

以硬脂酸、钛酸四丁酯为原料 ,用硬脂酸凝胶法制备了TiO2 超细粉末 .运用差热 热重 (DTA TG)、傅里叶红外光谱对制备过程进行了表征 ;用X射线粉末衍射 (XRD)、透射电镜 (TEM)对纳米晶的粒径和形貌进行了表征 .不同温度处理可得到不同晶型和形貌的纳米二氧化钛     

掺杂改性TiO2 /AC的制备及气相甲苯降解性能研究

以钛酸丁酯为前驱体,采用溶胶-凝胶法制备了Fe、N离子共掺杂的TiO2/AC和TiO2/ACF负载型光催化剂,采用SEM、XRD、UV-Vis分光光度计等分析方法对催化剂样品进行了表征。选取甲苯为室内气相空气污染物的模型化合物进行光催化降解实验,探讨了催化剂制备过程中离子掺杂量、抑制剂种类、焙烧温度以及载体等对光催化剂活性的影响。结果表明, 催化剂在ACF上的分散效果优于AC上,制备的光催化剂均以锐钛矿相存在,Fe、N离子共掺杂实现了光催化剂在可见光区和紫外光区的双增强;以冰醋酸为抑制剂、离子掺杂量分别为N 8%和Fe 8%,ACF为载体,500 ℃下焙烧2 h所得TiO2/ACF光催化剂对气相甲苯的降解活性最高。     

V~(5 )、Ho~(3 )共掺杂TiO_2光降解甲基橙(英文)

采用溶胶-凝胶法制备了不掺、单掺和共掺杂纳米TiO2,对样品进行了XRD和UV-Vis吸收光谱分析,并以甲基橙的光脱色反应考察了样品的光催化性能。结果发现V5 拓宽了TiO2光谱响应范围,提高了光的利用率,产生更多的电子-空穴对;Ho3 的掺杂抑制了TiO2粒径的长大,引起了晶格的畸变和膨胀,延缓了光生载流子的复合;V5 、Ho3 共掺杂时,由于两种掺杂物的共同作用,可进一步提高TiO2的光催化性能。     

Au NPs decorated TiO2 nanotubes array candidate for UV photodetectors

This work reports the Au nanoparticles (NPs) deposited on TiO2 nanotubes (NTs) which were successfully synthesized by a simple two-step anodization method. This fabrication process is notable for a simple and inexpensive method for obtaining pure TiO2 NTs and Au NPs deposited TiO2 NTs. The prepared samples were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and I-V curve. We found that the size of Au NPs can be controlled by changing the bias voltage during the deposition. The photodetectors of Au NPs/TiO2 devices showed good wavelength selectivity with high photocurrent as compared to pure TiO2 NTs devices. Subsequently, Au NPs deposited on TiO2 NTs at bias voltage of 70 V was potentially used in fabrication of UV photodetector. At this applied voltage, a high density of Au NPs was uniformly deposited on TiO2 NTs. As a result, it enables a high photocurrent and great responsivity in UV region. It is suggested that the Au NPs deposited TiO2 NTs device shows good promise for UV photodetectors with possibility to fine-tune properties in both UV and visible regions and is worthy of further investigation.     

负载型钼氧化物催化剂NH3选择性催化还原NOx

通过浸渍法制备了Mo/TiO2,Mn-Mo/TiO2和Mo-Mn/TiO2三种催化剂,采用X射线衍射(XRD)、比表面积测定(BET)、拉曼光谱(LRS)、原位红外(in situ FT-IR)、扫描电镜(SEM)等技术进行相关的微观表征分析.在模拟氨气选择性催化还原NO的反应条件下(NH3-SCR)对催化剂的脱硝反应...     

采用水解法制备壳-核式SiO2/TiO2复合颗粒

以钛酸丁酯、正硅酸乙酯为原料采用水解法制备了单分散的SiO2／TiO2复合微粒；运用傅里叶红外光谱(FTIR)、原子力显微镜(AFM)、透射电镜(TEM)和X射线衍射(XRD)等测试方法对所得复合微粒进行了表征．AFM和TEM的观察结果表明，SiO2／TiO2复合粒子呈核一壳结构，内核粒径约130nm、表面SiO2包覆层厚度约30nm．XRD分析表明复合微粒内核为锐钛矿型二氧化钛，表面包覆层为非晶态SiO2．此外紫外-可见吸收谱表明该复合微粒具有优良的紫外屏蔽和可见透过的光学特性。     

BiOI-TiO2复合材料光催化降解双酚A的研究

采用 Triton X-100/正己醇/环己烷/水的微乳体系合成了一系列BiOITiO2的纳米材料，分析了其晶体结构、表面结构和光谱特征，探讨了可见光光催化降解双酚A废水的可行性.结果表明: BiOI-TiO2的分散性能好、比表面积大.光催化结果表明，复合材料中BiOI与TiO2的摩尔比对光催化性能影响很大且比值达到75%时效果最好，光催化降解机理符合一级动力学方程，反应速率常数（kobs）与催化剂投加量及初始pH值有关.催化剂重复多次使用的降解效果稳定.     

纳米La 2O 3/TiO 2复合薄膜的抗凝血性研究

 采用射频磁控溅射方法制备了TiO₂薄膜和La₂O₃掺杂的TiO₂复合薄膜。利用扫描电子显微镜、X射线衍射,紫外可见光谱等材料表征方法研究La₂O₃掺杂对TiO₂薄膜的结构及抗凝血性能的影响。结果表明：La₂O₃掺杂促使TiO₂晶粒沿金红石相(110)晶面择优生长,能细化TiO₂纳米晶粒的大小,使薄膜的光学带隙由2.85 eV提高到3.2 eV。血小板粘附实验表明La₂O₃掺杂的TiO₂复合薄膜具有优良的血液相容性能;分析了复合薄膜的抗凝血机理。     

TiO2薄膜折射率的调控方法

采用电子束蒸发技术及其辅助工艺制备了TiO2薄膜,利用X射线衍射(XRD)、X射线光电子能谱(XPS)和原子力显微镜(AFM)对薄膜的组织结构进行了表征,采用紫外可见分光光度计研究了TiO2薄膜的折射率变化.结果表明:传统电子束蒸发镀制的TiO2薄膜的折射率低于块体值,通过调节氧气压、沉积速率和衬底温度可在1.97～2...     

Synthesis of TiO2 nanotubes film and its light scattering property

TiO2 nanotubes with diameters of 10 nm and lengths up to 600 nm were fabricated by directly using commercial TiO2 powders P25 as the precursors via sonication-hydrothermal combination approach. TiO2 nanotubes were characterized by means of X-ray powder diffractometer （XRD）, scanning electron microscope （SEM）, selected area electron diffraction pattern （SAED） and transmission elec- tron microscope （TEM）. The light scattering property of film electrodes modified with TiO2 nanotubes was studied and revealed that TiO2 nanotubes can be used as the light scattering centers to increase the light absorption in dye-sensitized solar cells. The TiO2 nanotubes film electrodes mixed with 10% small nanoparticles TiO2 had both strong light scattering property and fine mechanical characteristics, and this kind of electrodes can be used as electrodes in improving the conversion efficiencies of dye-sensitized solar cells.     

Formation of crystalline TiO2 by anodic oxidation of titanium

Formation of crystalline TiO2(anatase) films by anodic oxidation of titanium foils in ethylene glycol(EG) based electrolytes at room temperature has been investigated.By varying the anodizing parameters such as the amounts of water and NH4 F added,applied voltage and anodization time,anodic TiO2 films with different crystalline structures were obtained.Scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray powder diffraction(XRD) characterizations were employed to determine the morphologies and crystalline structures of as-prepared anodic TiO2 films.The results indicate that crystallization of anodic TiO2 films was generally facilitated by high fluoride concentration,high applied voltage and longer anodization time,and the formation of anodic TiO2 films with best crystallinity could only be achieved when optimized amounts of water were added.