乙酸修饰Ag/TiO2复合光催化剂的制备及协同催化性能

利用光化学还原法制备了Ag/TiO₂,然后通过乙酸浸渍制备了HAc-Ag/TiO₂复合光催化剂.利用X射线衍射（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）和紫外-可见漫反射光谱（UV-Vis DRS）等手段表征了催化剂的性质.以降解水溶液中的甲基橙（MO）为探针反应,考察了催化剂在可见光下的光催化性能.结果表明,乙酸对TiO₂的修饰在TiO₂禁带中产生了"带尾",使TiO₂的禁带宽度发生了显著的缩减;Ag纳米粒子和乙酸共同修饰的HAc-Ag/TiO₂样品具有更窄的禁带宽度和更正的价带顶位置;Ag和乙酸的协同作用使HAc-Ag/TiO₂具有良好的可见光催化活性：可见光照射2 h后,甲基橙在HAc-Ag/TiO₂上的降解率接近100%.     

Photocatalytic degradation of dimethyl phthalate ester using novel hydrophobic TiO2 pillared montmorillonite photocatalyst

TiO₂ pillared montmorillonites were prepared by introducing Ti⁴⁺ into a layer of montmorillonite modified with or without cetyltrimethylammonium bromide. The components and texture of the prepared composites were characterized by thermogravimetric analysis, X-ray powder diffraction and scanning electron misroscopy. The adsorption and photocatalytic degradation performance of a model environmental endocrine disruptor, dimethyl phthalate ester, were investigated using this newly prepared hydrophobic TiO₂ pillared montmorillonite photocatalyst. The adsorption of dimethyl phthalate ester from water varied from 9% to 28% on the prepared hydrophobic photocatalyst. Although the experimental results showed that the photocatalytic activity of the hydrophobic photocatalyst was slightly lower than that of hydrophilic one, electron spin resonance verified that hydroxyl radicals were also generated in hydrophobic TiO₂ pillared montmorillonite photocatalyst under UV irradiation. To elucidate the decomposition mechanism of dimethyl phthalate ester, 12 main photocatalytic intermediates were identified during the photocatalytic degradation process, and a plausible degradation mechanism was also proposed.     

Preparation of Ce-TiO2 catalysts by controlled hydrolysis of titanium alkoxide based on esterification reaction and study on its photocatalytic activity

The Ce-TiO2 catalysts were prepared by controlled hydrolysis of Ti(OC(4)H(9))(4) with water generated "in situ" via an esterification reaction between acetic acid and ethanol, followed by hydrothermal treatment. The samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), atomic absorption flame emission spectroscopy (AAS), and nitrogen adsorption-desorption methods. Both of undoped TiO2 and Ce-TiO2 samples exclusively consist of primary anatase crystallites, which further form spherical aggregates with diameters ranging from 100 to 500 nm. The photocatalytic activity of Ce-TiO2 was investigated for the photocatalytic degradation of Rhodamine B (RB) aqueous solution both under UV and visible light irradiation. Doping of Ce(4+) effectively improves the photocatalytic activity under both UV light irradiation and visible light irradiation with an optimal doping concentration of 0.2 and 0.4%, respectively. The photocatalytic mechanisms of Ce-TiO2 catalysts were tentatively discussed.     

银修饰的二氧化钛多孔微管的制备、表征及光催化活性

在冰乙酸存在条件下, 以四氯化钛水解法制备了具有锐钛矿晶型结构的二氧化钛多孔微管, 并用化学沉积法对其进行修饰, 得到银修饰的二氧化钛多孔微管. 采用XRD, TG-DTA, SEM, TEM, XPS及氮吸附等手段对其进行了表征. 氮吸附的结果显示该样品具有很高的比表面积, 银的修饰没有显著影响二氧化钛微管的孔结构; XRD的表征结果显示, 银修饰的二氧化钛多孔微管具有良好的锐钛矿晶型; XPS的分析结果表明银以游离的金属态存在; TEM的观测结果显示, 银团簇沉积于二氧化钛纳米晶粒的表面. 降解苯酚的光催化活性测试显示出银的修饰对二氧化钛的光催化活性有显著的提高作用, 其中含银2.0%的样品活性最高.     

氮和碳共掺杂TiO2纳米晶的制备及可见光催化性能

以钛酸四丁酯为钛源, 冰醋酸为抑制剂, 超细铵盐为固体载体, 采用新型溶胶-凝胶法制备了氮和碳共掺杂TiO2纳米晶(N-C-TiO2) 光催化剂. 透射电子显微镜(TEM)结果表明, N-C-TiO2样品颗粒均匀, 尺寸细小, 且分散性好; 热失重分析(TGA)、 X射线粉末衍射(XRD)和X射线光电子能谱(XPS)研究结果表明, 复合干凝胶经低温热处理, 使铵盐载体分解、 挥发去除, 样品为单一的锐钛矿相, N和C原子扩散进入晶格结点或间隙位置, 与TiO2化学键结合; 氮气等温吸附-脱附结果表明, 样品比表面积高达356 m2/g, 孔体积为0.27 mL/g. 以氙灯为可见光光源, 罗丹明B水溶液为模拟污染物, P25为参比催化剂, 在辐射强度为100 mW/cm2的可见光照射条件下, N-C-TiO2具有很高的光催化活性, 其可见光催化活性明显高于P25.     

Size-selective photocatalytic reactions by titanium(IV) oxide coated with a hollow silica shell in aqueous solutions

A novel core-shell composite photocatalyst, commercially available titanium(IV) oxide (TiO(2)) particles directly incorporated into a hollow amorphous silica shell, was fabricated by successive coating of TiO(2) with a carbon layer and a silica layer followed by heat treatment to remove the carbon layer. The composite induced efficient photocatalytic reactions when relatively small substrates were used, such as methanol dehydration and decomposition of acetic acid, without any reduction in the intrinsic activity of original TiO(2), but did not exhibit efficient photocatalytic activity for decomposition of large substrates, methylene blue and polyvinyl alcohol. The unique size-selective properties of the composites are due to their structural characteristics, i.e., the presence of a pore system and a void space in the silica shell and between the shell and medial TiO(2) particles, respectively. The loading of alkylsilyl groups on the surface of the composite led to highly photostable floatability: the floated sample also induced efficient photocatalytic reaction for decomposition of acetic acid while retaining floatation at the gas/water interface.     

双晶型TiO2薄膜的低温制备及表征

采用溶胶-凝胶法低温制备了具有锐钛矿、板钛矿双晶型的TiO2薄膜. 分别利用X射线衍射(XRD)、透射电子显微镜(TEM)、UV-Vis透光率曲线和原子力显微镜(AFM)等手段对所得TiO2溶胶和薄膜进行了性能表征. 采用光催化降解罗丹明B水溶液评价TiO2薄膜的光催化活性. 结果发现, 所得TiO2薄膜具有较高的透明度和光催化活性. 同时, 考察了溶胶回流温度对所制备TiO2薄膜性能的影响, 发现升高溶胶回流温度可以完善薄膜的晶型, 增大薄膜的粗糙度, 从而提高薄膜的光催化活性. 溶胶回流温度为100 ℃时所制备的TiO2薄膜具有最高的光催化活性.     

掺硼纳米TiO2的制备及光催化性能研究

采用改进的Sol-gel方法,制备了单分散椭球形微孔结构的掺B纳米TiO₂光催化剂,并用TG-DTA、XRD、XPS、UV-Vis、TEM、BET等手段进行表征.以难生化降解的染料罗丹明B为目标降解物,采用HPLC检测,通过不同光照时间下染料降解率考察了产物的光催化活性.结果表明,改进的Sol-gel法制得的光催化剂具有明显的孔结构,而且比表面积大、孔径分布窄、粒径小、分散性好;适量B的掺杂能够有效促进TiO₂纳米粒子的光催化活性.最佳催化剂制备条件:B掺杂的摩尔分数为20%、450℃煅烧2 h,此时所制得的B-TiO₂光催化剂活性比纯TiO₂有显著提高.     

超临界流体干燥法制备TiO2／C纳米粒子及光催化性能

以TiCl4为原料,采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级TiO2/C复合光催化剂.以苯酚的光催化降解对所得催化剂的催化活性进行了评价.结果表明,纳米TiO2/C复合粒子与单组分TiO2比较,复合粒子光催化活性高于单组分的TiO2,h苯酚降解率高达975 ％,COD为957%.并用XRD、TEM、 UV-Vis和XPS等手段进行了表征,iO2以锐钛矿型形式存在.比较了不同制备方法制得的TiO2/C复合催化剂,得出超临界干燥法制备的光催化剂具有粒径小,比表面积大,分散性好,光催化活性高等特点.     

Low-temperature synthesis and photocatalytic activity of TiO2 pillared montmorillonite

TiO2 pillared montmorillonite (PILM) was synthesized by hydrolyzing TiO2 sol into the interlayers of montmorillonite (MMT) at low temperatures. It is novel that all the as-prepared catalysts without calcination show a high photocatalytic activity for the degradation of acid red G (ARG) under UV light irradiation. The as-prepared powders were characterized by XRD, TEM, UV-vis diffuse reflectance spectroscopy, BET, and FT-IR. The X-ray diffraction analysis indicated that the (001) plane of MMT in the composites disappeared and that the layered structure became disordered, which also was confirmed by the TEM photographs. The UV absorption edge of the composites shows a red-shift in comparison to that of pure TiO2 particles. The obtained catalyst has the highest photocatalytic activity when the composite temperature is 70 degrees C, which could be attributed to the synergetic effects of the adsorbability of MMT and the photocatalytic property of TiO2 in it.     

溶胶-凝胶法制备复合MxOy-TiO2光催化剂

以无机盐TiCl4为原料制备TiO2溶胶,并利用溶胶胶粒修饰法制备SiO2 TiO2、ZrO2 TiO2、WO3 TiO3、MoO3 TiO2及Pt/TiO2光催化剂,用于光催化氧化甲醛反应,考察添加物对 催化剂光催化性能的影响.其中,SiO2 TiO2催化剂的光催化氧化降解甲醛性能最好,而MoO3 TiO2的催化性能最差.SiO2 TiO2催化剂优良的光催化性能可归于SiO2 TiO2催化剂的高 比表面积,高空隙率,小晶粒粒径和强吸光性能等性质的综合影响.     

Photocatalytic activity of Ho-doped anatase titanium dioxide coated magnetite

A composite photocatalyst (Ho/TiO(2)/Fe(3)O(4)) with Ho-doped anatase titanium dioxide (Ho/TiO(2)) shell and a magnetite core was prepared by coating photoactive Ho/TiO(2) onto a magnetic Fe(3)O(4) core through the hydrolysis of tetrabutyltitanate (Ti(OBu)(4), TBT) in water/oil (w/o) microemulsion with precursors of Ho(NO(3))(3) and TBT in the presence of Fe(3)O(4) nanoparticles. The morphological, structural and optical properties of the prepared samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Vis diffusive reflectance spectroscopy (UV-Vis DRS). The effect of Ho ion content on the photocatalytic activity was studied. The photodegradation behavior of the prepared photocatalyst under UV and visible light was investigated in aqueous solution using methyl orange (MO) as target pollutant. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photo-oxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ho/TiO(2) was tightly bound to Fe(3)O(4) and could be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.     

乙烯在Pt/Pt4+-TiO2上的可见光降解

以TiO2为主的光催化氧化技术存在太阳能利用率低(～5％)和光量子转化效率低(～4％)等缺点，使其工业应用受到制约，人们尝试用过渡金属离子掺杂和贵金属表面修饰等技术来提高催化剂对太阳能的利用率和光量子的转化效率，但目前将铂离子掺杂和铂金属表面修饰技术结合用于光催化     

Preparation and characterization of highly photoactive nanocrystalline TiO_2 powders by solvent evaporation- induced crystallization method

Highly photoactive bi-phase nanocrystalline TiO2 photocatalyst was prepared by a solvent evaporation-induced crystallization (SEIC) method, and calcined at different temperatures. The obtained TiO2 photocatalyst was characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results show that solvent evaporation can promote the crystallization and phase transformation of TiO2 at 100℃. When calcination temperatures are below 600℃, the prepared TiO2 powders show bimodal pore size distributions in the mesoporous region. At 700℃, the pore size distributions exhibit monomodal distribution of the inter-aggregated pores due to the collapse of the intra-aggregated pores. At 100℃, the obtained TiO2 photocatalyst by this method shows good photocatalytic activity, and at 400℃, its photocatalytic activity exceeds that of Degussa P25. This may be attributed to the fact t     

活性炭负载TiO2-Fe3O4磁性光催化剂的制备及性能

采用溶胶-凝胶法制备了易于固液分离的活性炭（AC）负载磁性光催化剂（TiO2-Fe3O4／AC）．样品通过SEM-EDX和X射线衍射法进行表征．通过在紫外光照射下降解亚甲基蓝评价其光催化降解能力．结果表明：负载22％Fe3O4的光催化剂（含20％TiO2和58％AC）的光催化活性最强（120min时亚甲基蓝的降解率达到87％,是纯TiO2的2．7倍）;磁性光催化剂可实现磁分离回收．     

球磨法制备复合光催化剂Bi12TiO20/ZnO及其光催化性能

本文用水作为分散介质,采用球磨法掺杂一定量的Bi₁₂TiO₂₀于ZnO中制备复合光催化剂Bi₁₂TiO₂₀/ZnO. 利用UV-Vis、XRD和SEM等仪器对样品进行了分析与表征. 通过对甲基橙的氧化来研究其光催化活性. 结果表明,光催化剂Bi₁₂TiO₂₀/ZnO对甲基橙氧化的催化活性高于氧化锌的催化活性.当Bi₁₂TiO₂₀的掺杂量为0.5%(质量分数),球磨时间为12 h,焙烧温度为300℃时,光照20 min后,复合光催化剂Bi₁₂TiO₂₀/ZnO对甲基橙的降解率可达到95.2%.     

超声微乳法合成TiO2-SiO2催化剂可见光光催化降解亚甲基蓝

采用可见光下亚甲基蓝的光催化降解为模型反应,考察了超声微乳法经钛酸丁酯水解合成的纳米TiO2-SiO2催化剂的性能,并用XRD和BET对催化剂进行了表征。结果表明:硅胶的加入有效地提高了TiO2-SiO2催化剂的热稳定性,抑制了热处理过程中TiO2由锐钛矿相向金红石相的转变和晶粒的长大。随着焙烧温度和TiO2含量的增加,TiO2的晶粒变大,但比表面积减少。TiO2-SiO2的光催化活性明显改善,可见光照射120min,31%TiO2/SiO2催化剂存在下,有84%亚甲基蓝光催化降解。31%TiO2/SiO2催化剂光降解亚甲基蓝的能力大大优于Degussa P-25和纯TiO2,其降解亚甲基蓝的反应速率常数分别为P-25和纯TiO2的8倍和10倍。     

低温下溶胶凝胶法制备TiO2纳米晶

从含过量水的溶胶出发,在室温下得到了TiO₂纳米晶。通过红外光谱,透射电子显微镜法和X射线粉末衍射法对含有过量水的溶胶体系中TiO₂纳米晶的室温形成机理进行了研究。与传统的溶胶凝胶法相比,在改良的溶胶凝胶体系中,在缩聚反应之前由于水过量使得钛的先驱体快速且充分的水解,从而生成[TiO₆]基团,随之形成TiO₂纳米晶。晶粒的尺寸为约3.5 nm,该法得到的TiO₂纳米晶比传统溶胶凝胶法得到的TiO₂纳米晶和商用光催化剂德固赛P25具有更好的光催化活性。     

掺杂纳米TiO2光催化性能的研究

利用浸渍法分别制备了Cr、Mn、Fe、Co、Ni、Cu六种过渡金属离子掺杂改性的二氧化钛光催化剂，以乙酸水溶液的光催化氧化反应和二氧化碳还原反应为探针,评价了掺杂催化剂的光催化性能.借助光电子能谱（XPS）、X射线衍射分析（XRD）等手段对掺杂催化剂进行了表征.研究结果表明，经过渡金属离子掺杂后，光催化性能均有不同程度的改善，改善程度按Cr、Co、Ni、Fe、Mn、Cu递增.掺杂后催化剂表面吸附氧的活泼性、金属离子的价态及得电子能力上的差异决定了不同离子掺杂纳米二氧化钛光催化性能的差异.     

磁载WO3－TiO2／SiO2／Fe3O4复合光催化剂的制备及其光催化活性

 用溶胶－凝胶法在表面包覆了SiO2的磁基体Fe3O4上负载TiO2,从而得到了易于磁性固液分离的磁载WO3－TiO2／SiO2／Fe3O4复合光催化剂,并通过IR,XRD,SEM和XPS等测试手段对催化剂进行了表征．研究了磁载WO3－TiO2／SiO2／Fe3O4复合光催化剂对亚甲基蓝溶液脱色的性能,并考察了WO3掺杂量对样品催化活性的影响．结果表明,n（WO3）／n（TiO2）＝0．001时,磁载WO3－TiO2／SiO2／Fe3O4复合光催化剂的催化活性最高,循环使用3次时脱色率仍保持在98％．