Mechanism and behaviors of Cr3+-doped TiO2

TiO₂ powder and TiO₂ thin film on the surface of glazed ceramic tile were prepared by sol-gel method. The influences of different doping Cr³⁺ concentration on the photocatalytic activity of TiO₂ were discussed, UV-visible and X-ray diffraction analysis were used to test the performance of TiO₂ powder and film. The results indicate that photocatalytic activity of doping Cr³⁺-TiO₂ thin film is higher than that of powder, and the interaction between Cr³⁺-doped and substrate can greatly enhance the photocatalytic activity. The results of X-ray diffraction and photoabsorption show that the Cr³⁺-doped energy level in TiO₂ is 0.62 eV high from the top of valence band, which belongs to the type of deep energy level doping. On the basis of the semiconductor energy level theory and Cr³⁺ dopant energy level, the semiconductor energy level model of Cr³⁺ in TiO₂ powder and thin film were established, and the doping mechanisms of Cr³⁺-doped in TiO₂ powder and thin film were analyzed. Foundation item: Project (20466001) supported by the National Natural Science Foundation of China     

纳米TiO2-SiO2自清洁复合薄膜制备及其光催化机理

采用溶胶-凝胶法在普通载玻片上制备TiO2-SiO2复合薄膜,研究SiO2添加量对光催化活性的影响,探讨TiO2光催化的机理．结果表明：光催化性随SiO2含量的增加而增加。但SiO2添加量过大,煅烧过程中对TiO2锐钛矿相晶粒生长有抑制作用,而且光催化活性有所下降．当SiO2添加量为30％时,在紫外光照1h时TiO2-SiO2薄膜的光催化活性最佳．     

Eu3+掺杂纳米TiO2光催化降解亚甲基蓝的研究

采用溶胶-凝胶法制备了Eu3+掺杂的纳米TiO2粉体。以亚甲基蓝溶液为目标降解物研究了掺杂纳米TiO2粉体的光催化性能,并讨论了掺杂TiO2粉体的加入量、亚甲基蓝溶液的初始浓度、pH值以及稀土元素掺杂量和烧成温度等对样品光催化性能的影响。结果表明:在样品加入量为0.15 g/50 mL,亚甲基蓝溶液的初始浓度为10 mg/L,pH=7时样品的光催化性能最佳。稀土元素的最佳掺杂量(摩尔比)为n(Eu3+)∶n(TiO2)=0.5%,样品的热处理温度在500～550℃时,样品表现出较好的光催化活性。掺杂TiO2粉体对亚甲基蓝有良好的降解效果,反应4 h降解率达到88.16%,优于同等条件下制备的纯TiO2粉体。     

Fe^3＋掺杂TiO2纳米薄膜及其光催化性能

用溶胶-凝胶法制备了Fe^3＋掺杂纳米TiO2薄膜，研究了不同Fe^3＋掺杂浓度的TiO2薄膜材料的光学性能、晶体结构和光催化性及三者之间的关系，并对相关机理进行了探讨．研究表明：铁掺杂量的不同使TiO2材料的光学性能、晶胞参数及光催化性等发生变化，其中以Fe^3＋掺杂0．3％～0．4％（摩尔分数）时具有最好的光催化性能，此时纳米TiO2薄膜具有锐钛矿结构，可见光透过率大于70％，紫外吸收限为366nm，比未掺杂的红移了6nm．     

Preparation of Nanometer-structured TiO_2 Thin Films by Sol-Gel Method

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｉＯ2 ｎａｎｏｍｅｔｅｒｔｈｉｎｆｉｌｍｉｓａｖｅｒｙｉｍｐｏｒｔａｎｔｆｕｎｃｔｉｏｎｍａｔｅｒｉａｌ .Ｉｔｈａｓａｖｅｒｙｇｏｏｄｐｒａｃｔｉｃａｌｖｉｓｔａｉｎｓｏｌａｒｅｎｅｒｇｙ ,ｐｈｏｔｏ ｅｌｅｃｔｒｏｃｈｅｍｉｃａｌ ,ｅｎｖｉｒｏｎｍｅｎｔｈａｎｄｌｅｏｆｏｒｇａｎｉｃｃｏｎ ｔａｍｉｎａｔｏｒ,ｅｔｃ[1- 4] ,ｓｏｍｏｒｅａｎｄｍｏｒｅｒｅｓｅａｒｃｈｗｏｒｋｈａｓｂｅｅｎｐｕｔｉｎｔｈｉｓａｓｐｅｃｔ.Ｓｏｌ ｇｅｌｍｅｔｈｏｄｉｓａｖｅｒｙｕｓｅｆｕｌ…     

掺铁二氧化钛光催化氧化罗丹明B溶液的反应机理初探

用UV-Vis、MS进行了掺铁二氧化钛光催化降解罗丹明B溶液的研究，初步证明罗丹明B在不同酸度条件下制备的二氧化钛催化剂的作用下遵循不同的光催化反应机理。     

Preparation and photocatalytic activity of Cu^2＋-doped TiO2/SiO2

Cu2+-doped nanostructured TiO2-coated SiO2. (TiO2./SiO2) particles were prepared by the layer-by-layer assembly technique and their photocatalytic property was studied. TiO2 colloids were synthesized by the sol-gel method using TiOSO4 as a precursor. The experimental results showed that TiO2 nanopowders on the surface of SiO2 particles were well distributed and compact. The amount of TiO2 increased with the increase in coating layers. The shell structure appeared to be composed of anatase titania nanocrystals at 550℃. The 2-layer coated TiO2 particles on the surface showed a higher degradation rate compared with all the dif-ferent-layer samples. The photocatalytic activity of Cu2+-doped TiO2/SiO2 was higher than that of undoped TiO2/SiO2. The optimum dopant content was about 0.10wt%.     

Preparation of TiO_2 Thin Film and Its Antibacterial Activity

1　IntroductionInrecentyears ,theuseofinorganicantimicrobialagentshasattractedinterestforthecontrolofmicrobes[1-3 ] .Thekeyadvantagesofinorganicantimicro bialagentsareimprovedsafetyandstability ,ascomparedwithorganicantimicrobialagents .Atpresent,mostanti…     

Mn~(2+)掺杂对纳米TiO_2薄膜光催化活性的影响

采用溶胶-凝胶法制备Mn2+掺杂的TiO2薄膜光催化剂,进行甲醛的光催化实验,考察Mn2+掺杂量、薄膜焙烧温度、溶胶体系pH值及薄膜厚度对光催化性能的影响.结果表明,Mn2+掺杂量为1.0%,焙烧温度500℃1 h,加硝酸溶胶体系pH=4,镀膜5层时,Mn2+掺杂TiO2薄膜光催化活性最高.150 min后甲醛降解率达79%,是单纯TiO2薄膜的1.4倍.     

Grain Size and Photocatalytic Activity of Nanometer TiO_2 Thin FilmsPrepared by the Sol-gel Method

Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness , crystalline phase, grain size, surface hydroxyl amount and so on were characterized by scanning electron microscopy (SEM) , X-ray diffraction (XRD), transmission electron microscopy ( TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer ( UV-VIS). The photocatalytic activity of TiO2 thin films was evaluated for the photocatalytic decolorization of aqueous methyl orange . The effects of film thickness on the crystalline phase, grain size, transmittance and photocatalytic activity of nanometer Ti02 thin films were discussed.     

Preparation and Characterization of Fe^3＋ -doped Nanometer TiO2 Photocatalysts

Fe^3＋ -doped nanometer TiO2 photocatalysts were prepared by sol-gel technique. TiO2 powders with different Fe^3＋ / Ti^4 ＋ molar ratios ranging from 0. 05% to 25% were synthesized by calcinating the gels in the temperature range of 200-600 ℃ . The effects of the content of iron ions and calcination temperature on the physical properties of the powders and their photocatalytic activities were examined by the photodecorapositon of methyl orange in sunlight. The results show that Fe dopant can decrease the temperature of nanatase-ratile transformation. The ideal photocatalytic property was achieved when the sample with an Fe^3＋ / Ti^4＋ ratio of 20 at% was calcined at about 300 ℃ for an hour, which is superior to that of commercial Degussa P-25. The optimum microstructure of the Fe-doped TiO2 for a high photocatalytic activity in sunlight is consisted of nanatase and ratile.     

钐掺杂二氧化钛粉体的制备及其光催化降解性能研究

采用微波水热法,以钛酸丁酯和氯化钐为原料,在冰醋酸催化作用下,制备出钐掺杂二氧化钛粉体.用XRD对所制备的粉体进行了表征,并以甲基橙染料为目标降解物,考察了钐掺杂量对粉体光催化降解性能的影响.结果表明,微波水热法最佳制备工艺是：1%wt钐掺杂,170℃下微波水热30 min后于80℃干燥24 h.钐掺杂二氧化钛的光催化降解能力显著高于纯TiO2,且随掺杂量的增加而增长,当钐掺杂量达1%时,光催化降解能力趋于稳定.     

Eu掺杂TiO_2纳米晶光致发光影响因素

为了寻找Ti O2∶Eu3+纳米晶的最佳制备工艺条件,采用溶胶-凝胶法制备了Ti O2∶Eu3+纳米晶,研究了Eu3+掺杂浓度、退火温度、Al3+的掺入等工艺参数对Ti O2∶Eu3+纳米晶发射光谱的影响.利用PL、PLE对样品进行了表征.结果表明用468 nm激发光源激发Ti O2∶Eu3+纳米晶时,样品显示出强红光发射,对应于Eu3+粒子的5D0→7F2超灵敏跃迁;且荧光强度随着Eu3+掺杂浓度和退火温度的升高先增强后减弱;700℃退火的样品红光发射强度达到最强,Eu3+的最佳掺杂浓度为0.8%mol;Al3+的掺入可以提高Eu3+的红光发射强度,采用钛酸正四丁脂∶异丙醇∶冰乙酸∶水=1∶4∶4∶2制备出的Ti O2:Eu3+纳米晶的红光发射光谱最强.     

铬银共掺杂改性纳米TiO2光催化剂及其光催化性能研究

以钛酸四丁酯为原料,利用溶胶凝胶法制备了Cr/Ag共掺杂的TiO2纳米材料.采用XRD、SEM、EDS等测试分析技术对掺杂纳米TiO2粉体进行了表征;以甲基橙为降解物,在太阳光照射条件下研究了掺杂对光催化活性的影响.研究结果表明:掺杂后的纳米TiO2的光催化性能明显提高,优于纯TiO2.当共掺杂的比例为Cr 1.0%/Ag 0.5%时,样品的效果最佳,对甲基橙的3h降解率达到97.63%.     

Cu2+掺杂混晶纳米TiO2粉体的制备及光催化活性

利用溶胶-凝胶法在不同温度煅烧2h制备了1%Cu2 掺杂的TiO2粉体,并用XRD技术对样品进行了表征.研究了煅烧温度对TiO2粉体相结构和光催化降解亚甲基蓝的活性的影响,利用相结构与TiO2粉体光催化活性关系探讨了Cu2 掺杂对纳米TiO2的光催化活性.结果表明,Cu2 的掺杂对TiO2的相转变有很大的促进作用.于540℃处理的掺杂Cu2 的TiO2粉体光催化活性最佳,降解率为95.31%,其金红石相含量为15%.     

煅烧时间对多孔TiO2-Al2O3复合光催化材料的影响

采用溶胶-凝胶法合成多孔TiO2-Al2O3复合光催化剂,对其进行XRD、SEM、FT-IR、N2吸附-脱附等表征,考察煅烧时间对光催化剂活性的影响.结果表明,所制备的样品为锐钛矿相TiO2和非晶态Al2O3的复合氧化物,煅烧时间增加使TiO2晶体的粒径有微小增长;样品颗粒表面非常粗糙,具有比较大的比表面积,平均孔径在10～16nm之间;随着煅烧时间的增加,样品的光催化活性和吸附性能呈现先增大后下降的趋势;煅烧时间为3h时,样品的光催化活性和吸附性能最好.采用TiO2-Al2O3复合光催化剂经90 min光照后,甲基橙溶液的降解率达到77.0％,总脱色率可达95.1％.     

液位沉降法制备 Ti O2薄膜及其性能研究

以钛酸丁酯为前驱液,无水乙醇为溶剂,乙酰丙酮为稳定剂,制备了 TiO2溶胶,采用液位沉降法在清洁的玻璃衬底上镀制TiO2薄膜。研究了添加剂聚乙二醇（1000）、p H、衬底温度对 TiO2溶胶在玻璃基板上附着性的影响;研究了液位沉降速度、容器倾角以及溶胶附着性对TiO2薄膜厚度的影响。考察了TiO2薄膜的表面形貌、晶相、光催化性能。结果表明,采用PEG与 Ti4＋的质量比为1,不调节pH的TiO2溶胶,在沉降速度为7 cm/min ,容器倾角为30°所制得的TiO2薄膜的光催化性能最好,光照3 h时其光催化降解率高达52.1％。     

Preparation and photocatalytic activity of Gd-doped TiO2 nanofibre

In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows： Firstly, potassium carbonate, titanium dioxide and proper gadolinium oxide （dopant） were calcined in the muffle at high temperature and the doped gadolinium K2Ti4O9 fibres were obtained; secondly, the fibre was heated using glycerol as solvent until Gd-doped TiO2 nanofibres were obtained. The synthesized samples were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that Gd-doped TiO2 nanofibre heat-treated by glycerol solvent can inhibit the agglomeration, so the grain diameter of the fibre is smaller than that without heat-treated with glycerol. Meanwhile, the diameter of the fibre decreases with the increase of the heating temperature and time. 97%- 98% of Gd-doped TiO2 nanofibre is anatase. The photocatalysis results showed that the photocatalysis activity of Gd-doped TiO2 nanofibre is just a little lower than that of TiO2 powder.     

TiO2光电导测量简介

扼要介绍TiO2的能带结构、表面吸附态以及几种测定TiO2表面光电导的方法，为进一步研究TiO2表面载流子的行为，揭示表面吸附物种在光催化反应中所起的作用和机理提供方法上的参考．     

微波辐射制备TiO2薄膜光催化性能研究

采用微波辐射法由溶胶制备出TiO2薄膜,用XRD和TEM对催化剂进行了表征。以甲基橙为模拟污染物,考察了微波功率和膜层厚度对TiO2光催化活性的影响,并实际考察了TiO2薄膜对啤酒废水的降解效果。结果表明：制备的TiO2薄膜具有较高光催化活性,微波功率300W时光催化活性最大,对啤酒废水具有良好的处理效果。