氮掺杂二氧化钛纳米管制备与光催化性能

以多孔氧化铝为模板,采用溶胶凝胶法制备出二氧化钛纳米管,在氨气气氛下进行了氮掺杂。用TEM、XRD、DRS等对其进行了表征,并通过降解碱性藏花红溶液研究了其光催化的性能。结果表明,用模板法制备的二氧化钛纳米管管径均匀、可控且排向一致,从DRS光谱可以推测出氮掺杂后的二氧化钛纳米管在可见光区有较强的吸收,并且与二氧化钛纳米管相比氮掺杂的二氧化钛纳米管的降解碱性藏花红溶液的效率更高。     

钽掺杂二氧化钛薄膜的溶胶-凝胶法制备及光电性能调控

用溶胶凝胶法在石英基板上制备不同钽掺杂浓度的二氧化钛薄膜,并采取后续氢气退火的方法改善其光电性能以用于TCO薄膜。采取SEM、XRD等测试手段观察薄膜的微观形貌、结晶性能及组成态,并利用四探针测试、可见光透过率测试和椭偏测试得出薄膜的电学和光学性能。结果表明掺杂钽元素以Ta~(5+)形式存在于TiO_2晶格中,大大提高了二氧化钛薄膜的n型导电性能,这是由于掺钽后费米能级向导带方向移动所致。氢气退火后二氧化钛晶粒尺寸变大且均匀,薄膜的结晶性能得到改善,并且由于引入了更高浓度的氧空位,导电性能得到明显的提升。最终获得了钽掺杂浓度为8%、电阻率为7.95Ω·cm、可见光区域的透过率约为75%的钽掺杂氧化钛薄膜,有潜力应用于透明导电薄膜生产领域。     

掺杂镧铈对纳米二氧化钛薄膜光催化性能的影响

研究采用溶胶-凝胶法制备了掺杂稀土元素La和Ce的TiO2薄膜,并以甲基橙为光催化降解反应化合物,进行了光催化实验,考察了掺杂对薄膜光催化性能的影响。结果表明,两种稀土元素中,掺镧的效果好于掺铈。该研究结果为光催化技术的实用化研究提供了可靠的依据。     

钯氮共掺杂TiO_2薄膜的光催化还原性能

采用磁控溅射法制备钯氮共掺杂二氧化钛薄膜,研究了Pd含量对薄膜的表面形貌、吸收光谱和可见光催化还原性能的影响。结果表明:Pd、N共掺杂TiO_2薄膜具有锐钛矿相和金红石相混合的结构,Pd的掺杂使TiO_2从锐钛矿相向金红石相转变。Pd元素主要以PdO的形式存在于薄膜表面。随着Pd含量的提高薄膜表面粗糙度增大,致密度减小。薄膜吸收光谱的吸收限,逐渐向可见光方向移动。Pd含量为0.4%(原子百分比)的薄膜,具有最优的可见光催化还原性能。     

纳米La-TiO2光催化降解甲基橙废水的研究

采用溶胶-凝胶法制备了纯TiO2和La掺杂TiO2复合纳米粉体,通过XRD,UV-Vis等测试手段分析了在紫外光照射下,以降解甲基橙为探针反应研究其可见光催化性能。结果显示样品均为锐钛矿相纳米TiO2,稀土元素镧掺杂后纳米TiO2特征衍射峰宽化,强度降低;掺入的La主要以La2O3的形式存在,同时有一部分形成Ti-O-La键;La掺杂可减小TiO2晶粒尺寸及增大催化剂比表面积;与未掺杂的二氧化钛相比较,适当含量的镧掺杂可有效促进TiO2表面光生载流子的分离,从而显著提高其光催化活性。当La/Ti的摩尔比为0.010时,可见光催化性能最好。     

掺氮二氧化钛薄膜的常压化学气相沉积及其结构性能研究

用常压化学气相沉积（APCVD）法，以四氯化钛（TiCl4）、氧气（O2）和氨气（NH3）作为气相反应先驱体，成功制备了掺氮二氧化钛（TiO2）薄膜。XRD、XPS和UV—Vis透射光谱研究表明，氮掺杂在二氧化钛薄膜中引入Ti4O7相，抑制了锐钛矿相向金红石相的转变；氮掺杂促使光吸收限红移，提高了薄膜在可见光照射下的光催化效率，并改善了薄膜表面的亲水性能。该工艺成本低廉，成膜速度快（150nm／min），适用于工业化浮法玻璃生产线，产业化前景广阔。     

镧铁掺杂的纳米TiO2薄膜的光吸收性能研究

采用溶胶-凝胶法,以钛酸四丁酯为原料,在生物载波片上制备了金属离子镧铁双元掺杂纳米TiO2薄膜,经过440℃高温热处理后,TiO2为锐钛矿型;通过紫外可见分光光度计测量薄膜的透射光谱,发现掺杂后TiO2的吸收边有改变,薄膜对可见光的吸收也明显加强.     

WO3+掺杂对纳米TiO2薄膜可见光致亲水性的影响

用溶胶-凝胶法和浸渍-提拉工艺在载波片上制备了均匀、透明的WO^3＋掺杂的纳米TiO2薄膜.用XRD、紫外-可见分光光度计分析了样品的晶相和光吸收性能,研究了WO^3＋的掺杂、掺杂量及热处理温度对薄膜可见光致亲水性的影响,并考察了薄膜在停止光照后,其亲水性能的变化.结果表明,与纯TiO2薄膜相比,掺WO^3＋的TiO2薄膜对可见光的吸收有所增强,并有一定的红移现象,且在可见光照射下,亲水性能都有提高,WO^3＋的最佳掺杂量为3%（物质的量比）;薄膜的最佳煅烧温度为773K;停止光照后,掺WO3＋的TiO2薄膜亲水性能持续的更久.     

CuAl2O4掺杂改性TiO2薄膜的制备与可见光催化性能研究

采用溶胶-凝胶方法在玻璃基片上制备了CuAl2O4掺杂改性的复合薄膜．研究了CuAl2O4的掺杂量、光照时间、薄膜厚度对TiO2复合薄膜光催化性能的影响，利用可见-紫外分光光度计测定酸性红B降解前后516nm处的吸光度，依此计算出薄膜对染料的降解率．借助于紫外可见光谱、X射线衍射、接触角测定仪等研究了薄膜的结构与性能．结果表明：随着CuAl2O4掺杂量的增加，TiO2复合薄膜对酸性红B水溶液的可见光降解脱色率增大．采用吸收光谱确定了CuAl2O4掺杂量为0％、0．5％、1％、1．5％％（摩尔分数）的TiO2复合薄膜的激发极限波长，分别是350、370、380、430nm，吸收边向可见区红移了20-80nm，可见光吸收范围明显扩大．     

Fe3+-TiO2薄膜经不同温度退火后的可见光催化性能

采用溶胶-凝胶法制备了掺杂Fe3+的TiO2薄膜,并在不同温度热处理.用SEM、XPS、UV-vis等分析方法进行结构表征和性能测试,通过降解亚甲基蓝溶液测试其可见光光催化活性.结果表明,723K时掺杂Fe3+的TiO2薄膜已经结晶,粒径为40～50nm.掺杂元素以Fe3+并口Fd2+形式存在于TiO2晶格并取代Ti4+形成Ti-O-Fe键,改变了TiO2的表面态,使TiO2带隙变窄,促进了对可见光的吸收.降解实验结果表明,823K热处理后掺杂铁的TiO2薄膜其光催化活性最好,在25W白炽灯模拟可见光下照射3.0h后,亚甲基蓝溶液的降解率接近30%.     

Structural and optical properties of nitrogen‐iron co‐doped titanium dioxide films prepared via sol‐gel dip‐coating: Effect of urea and iron nitrate concentration in the sol

In this study, nitrogen‐iron co‐doped titanium dioxide films were prepared via sol‐gel dip‐coating method using urea and iron nitrate as nitrogen and iron source, respectively. Nonmetal doping of TiO₂ have some disadvantages such as massive charge carrier recombination and losing the photo‐catalytic capability. Three different nitrogen‐iron co‐doped titanium dioxide sols with different urea and iron nitrate concentration were prepared. The resulting sols were homogeneous and transparent, and no precipitation was observed in any of them. It was observed that the film prepared with middle urea‐iron nitrate concentration sol got opaque in a short time after the dip‐coating process. All prepared films were characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, confocal microscopy and ultraviolet–visible (UV‐Vis) spectroscopy. It was found that the concentration of the urea and iron nitrate in the sol had an effect on the crystal structure, microstructure, surface morphology and optical properties of the resulting films. Samples with middle concentrations had amorphous structure and bigger particle size. It was seen that sample with higher iron amount has lower band‐gap. It is concluded that we can prepare transparent anatase, transparent amorphous and opaque amorphous titanium dioxide films by changing the urea and iron nitrate concentration in the sol.     

Visible light enhanced TiO2 thin film bilayer dye sensitized solar cells

Visible light enhanced nitrogen-sulfur (N-S) doped titanium dioxide (TiO₂) thin films were prepared by the sol-gel method using thiourea as a dopant. The physical and chemical properties of the TiO₂ thin films were greatly influenced by the amount of thiourea added to the sol-gel solution. The greatest shift to longer wavelengths for visible light absorption was observed with 0.6 g of thiourea in the precursor solution, while 0.4 g yielded the largest particle sizes. These single-cycle dip-deposited N-S doped TiO₂ thin films were used as visible light harvesters as well as blocking layers in dye sensitized solar cells. When deposited directly on conducting fluorine doped tin oxide electrodes, photo-conversion efficiencies were reduced. However, the opposite configuration, with N-S doped thin films on top of nanoporous TiO₂, yielded an increased open-circuit voltage of 0.84 V, a short-circuit current density of 9.86 mA cm⁻², and an overall conversion efficiency of 5.88% greater than that of a standard cell. The effectiveness of the blocking layer on the cell efficiencies was analyzed by electrochemical impedance spectroscopy.     

Visible-light absorption and photocatalytic activity of Cr-doped TiO2 nanocrystal films

Chromium doped titanium dioxide (TiO₂) nanocrystal films with various doping concentration have been successfully prepared by a sol–gel dip-coating process. These films have been characterized by XRD, XPS, AFM, and UV–vis absorption spectroscopy. It is found that Cr doping can effectively reduce the transition temperature of anatase to rutile phase as well as the grain size. The absorption edges of TiO₂ thin films shift towards longer wavelengths (i.e. red shifted) from 375 nm to about 800 nm with increasing Cr concentration, which greatly enhances TiO₂ nano-materials on the absorption of solar spectrum. The appearance of UV–vis absorption features in the visible region can be ascribed to the newly formed energy levels such as Cr 2p level and oxygen vacancy state between the valence and the conduction bands in the TiO₂ band structure. The enhancement of the photocatalytic properties is observed for Cr-doped TiO₂ thin film.     

APCVD法制备掺氮二氧化钛薄膜及其性能研究

采用常压化学气相沉积(APCVD)法,以四氯化钛(TiCl4)、氧气(O2)氨气(NH3)作为先驱体,成功制备了掺氮二氧化钛(TiO2)薄膜.通过对其进行扫描电镜(SEM)、X射线衍射(XRD)、紫外可见透过光谱(UV-VIS)研究后发现,氮掺杂后在二氧化钛薄膜中引入Ti4O7相,抑制了锐钛矿相向金红石相的转变,光吸收限发生红移,相应从365.8nm红移到了402.6nm,提高了薄膜在可见光照射下的光催化效率,并改善了薄膜表面的亲水性能.     

Nitrogen-doped titanium dioxide—Characterization of structural and optical properties

We have chosen oxidation of titanium nitride, TiN, in air atmosphere as a preparation method of nitrogen-doped titanium dioxide for photocatalytic application. Powders and thin films were selected for systematic studies. Self-propagating high-temperature synthesis (SHS) and dc reactive magnetron sputtering were used for elaboration of stoichiometric TiN powder and thin films, respectively. Samples microstructure was studied by means of AFM and SEM. The phase and chemical composition were investigated by means of XRD and XPS. The optical spectra were measured over the visible and UV ranges of light spectrum. SEM images of powders revealed a change in grain shape from sharp-edged TiN grains with well-defined facets to regular and oval TiO₂. XRD studies set out the temperature limit of TiN existence at 400 °C. XPS investigations confirmed nitrogen presence in TiO₂ lattice even at 500 °C. Optical analysis revealed an additional absorption over the visible range - powders, and a shift of the fundamental absorption edge towards visible range of the light spectrum - thin films.     

银钠米粒子/二氧化钛复合薄膜的溶胶凝胶法制备及其光学性质的研究

用溶胶凝胶法制备了含纳米级银粒子的TiO2 薄膜。对薄膜进行了XRD、TEM、XPS等测试 ,发现空气中 60 0 - 80 0℃热处理形成了含 4 - 4 5nm的Ag金属粒子的锐钛矿和金红石多晶薄膜。Ag微粒子随热处理温度升高而增长。这些薄膜在可见光区有一个较宽的吸收峰。     

锐钛矿型TiO2纳米棒薄膜的溶胶-凝胶法制备研究

以钛酸丁酯Ti（OC₄H₉）₄、冰醋酸、去离子水和聚乙二醇（PEG）1000为原料,采用溶胶-凝胶法和旋转涂膜工艺,在玻璃衬底上制备出锐钛矿型TiO₂纳米棒。利用X射线衍射仪（XRD）、SEM和紫外可见光谱（UV/Vis）对TiO₂纳米棒薄膜进行了表征。结果表明,实验制备的TiO₂纳米棒为锐钛矿晶型,在TiO₂反应体系中,胶体粒子在加热过程中偶联在一起,1h后形成了TiO₂纳米棒,其直径为30～50nm,长度为100～200nm。同时,在42mL钛的胶体溶液中添加0.30g PEG（1000）后,纳米TiO₂薄膜的可见光透射峰值降低,TiO₂薄膜表面孔径为20～50nm。     

Fe3+-SiO2掺杂纳米TiO2的制备及其光催化降解甲基橙的研究

以三嵌段非离子表面活性剂P123为模板,采用水热法制备了Fe3+-SiPO2掺杂纳米TiO2,通过X射线衍射(XRD)、红外光谱(FT-IR)、紫外-可见吸收光谱(UV-Vis)等手段考察了Fe3+-SiO2掺杂纳米TiO2的结构与光学特性.实验结果表明:Fe3+、SiO2掺杂进入TiO2的晶格,可获得高纯度锐钛矿相纳米TiO2.Fe3+和SiO2的加入有助于抑制金红石相的形成和晶粒长大,提高了TiO2的热稳定性.Fe3+-SiO2掺杂将TiO2的光响应范围拓宽至可见光区,提高了纳米TiO2的光催化性能.与纯纳米TiO2相比,Fe3+-SiO2掺杂纳米TiO2光催化降解甲基橙的性能显著提高.     

Physico-chemical, photoelectrochemical and photocatalytic properties of electrodeposited nanocrystalline titanium dioxide thin films

Crystal structure and microstructural properties of titanium dioxide (TiO₂) thin films prepared by cathodic electrodeposition on indium-tin-oxide coated glass substrates from aqueous peroxo-titanium complex solutions have been investigated. The electrodeposited TiO₂ thin film electrode exhibited anodic photocurrent upon visible light irradiation, indicating the typical behavior of n-type semiconductor. The photodecomposition of CH₃CHO by such thin films on exposure to ultraviolet light illumination was also observed.     

Preparation of regularly structured nanotubular TiO2 thin films on ITO and their modification with thin ALD-grown layers

Nanotubular titanium dioxide thin films were prepared by anodization of titanium metal films evaporated on indium tin oxide (ITO) coated glass. A facile method to enhance the adhesion of the titanium film to the ITO glass was developed. An optimum thickness of 550 nm for the evaporated titanium was found to keep the film adhered to ITO during the anodization. The films were further modified by growing amorphous titania, alumina and tantala thin films conformally in the nanotubes by atomic layer deposition (ALD). The optical, electrical and physical properties of the different structures were compared. It was shown that even 5 nm thin layers can modify the properties of the nanotubular titanium dioxide films.