溶胶-凝胶法制备薄膜型TiO2光催化剂

用TiCl4作原料,通过溶胶-凝胶法在单晶硅基片上制备了TiO2纳米薄膜,并用XRD,AES,XPS以及紫外反射光谱等手段,对TiO2薄膜的结构进行了研究.结果发现,TiO2薄膜以锐钛矿型晶相存在.TiO2薄膜层与硅衬底间无明显的界面扩散反应.掺杂的Pd在还原前的薄膜中以氧化态存在,还原后则以高分散的金属态存在.掺杂的Pt在还原前后均以金属态存在,但还原后产生颗粒聚集.掺杂Pd的TiO2薄膜经还原后,其紫外吸收强度明显提高,主吸收峰发生红移.     

La掺杂TiO2光催化剂的制备与表征

用共沉淀法和溶胶-凝胶法制备了La掺杂TiO2光催化剂(La3 -TiO2),并以罗丹明B为模型反应物,进行了光催化降解实验.结果发现,共沉淀法制备的La3 -TiO2具有较高的光催化活性,当掺La量为1.0%、于800℃煅烧2 h时获得的催化剂活性最佳.用X射线衍射、N2吸附、扫描电镜和电子探针等手段测定了两种方法制备的典型样品的结构和粒度分布.两种方法制备的催化剂都是含有锐钛矿和金红石型TiO2的混合晶体,但共沉淀法制备的催化剂具有较高的锐钛矿含量、较大的晶粒和大孔/介孔的多级孔结构,这是其具有较高光催化活性的主要原因.     

溶胶—凝胶工艺制备TiO2薄膜的表面组成和价态研究

通过Ｘ射线光电子能谱（ＸＰＳ）和电子自旋共振谱（ＥＳＲ）,确定了采用溶胶－凝胶工艺制备的ＴｉＯ２光催化纳米薄膜中元素的化学组成和价态。实验结果表明,薄膜中除含有钛和氧元素外,还有一定量的来自有机前驱物中未完全燃烧的残余碳和少量从玻璃表面扩散到薄膜中的钠和钙离子;Ｔｉ除了以Ｔｉ＾４＋价形态存在外,还有一定量的Ｔｉ以Ｔｉ＾３＋和Ｔｉ＾２＋形式存在,这种情况主要是由于有机基团的燃烧,来自玻璃基体中钠与钙     

复合光催化剂CeO2/TiO2的制备及性能研究

采用溶胶-凝胶-浸渍法制备了CeO2／TiO2二元复合纳米光催化剂,用XRD、FTIR等对其进行了表征。以紫外灯为光源,直接耐晒兰(DFB)的脱色为模型反应,研究了CeO2／TiO2的光催化活性。结果表明：掺杂摩尔百分比x(CeO2)=1．44％、600℃煅烧2h时,该催化剂的催化活性最高,比纯TiO2高近1倍。DFB脱色的最佳条件为：pH9．0～10．0,投加量200mg／50mL,空气流量200mL／min。     

TiO2薄膜光催化氧化I-的研究

采用溶胶凝胶法,在玻璃珠表面涂覆均匀透明的TiO₂薄膜并制成光催化反应器,对水溶液中I-的光催化氧化进行了研究.比较了光催化剂的活性,讨论了I^-的起始浓度、试液的酸度、光照时间与I₂产率的关系.实验结果表明:采用锐钛型TiO₂作光催化剂(3L碘化钾溶液所用催化剂量为40g),当[I^-]=0.3mol/L,[H⁺]=3.0mol/L,光照8h时,I₂的产率达到41.26%.     

B掺杂TiO2/AC光催化剂的制备及活性

以硼酸和钛酸丁酯为主要原料，以活性炭(AC)为载体。用溶胶-凝胶法制备了B掺杂TiO2／AC光催化剂．用X射线衍射(XRD)、紫外可见漫反射吸收光谱(UV—VIS)对制得的光催化剂进行了表征．以甲基橙水溶液的光催化脱色反应和氧化乐果水溶液的光催化降解反应。考查了不同B掺杂TiO2／AC光催化剂的活性．结果表明，所有B掺杂TiO2／AC光催化剂均为锐钛矿晶相．B的掺杂未导致TiO2／AC光催化剂的吸收带边发生明显的移动．当B-TiO2质量分数分别为2．0％和2．5％时，TiO2／AC光催化剂的活性有明显的提高．B-TiO2质量分数2．0％时活性最高．但是，当B-TiO2质量分数分别为1．5％和3．0％时。TiO2／AC光催化剂的活性降低．B的缺电子特性可能改变了TiO2能带中的电子密度，使光催化反应中光生电子和空穴的俘获方式发生变化；同时。B的缺电子特性也会使光催化剂表面的Lewis酸强度增强，导致表面吸附OH-数量和目标反应物的吸附方式发生变化．这些可能是B-TiO2／AC光催化剂活性发生变化的主要原因．     

WO3-TiO2薄膜型复合光催化剂的制备和性能

 采用溶胶－凝胶法在多孔钛片上制备了WO3－TiO2薄膜型复合光催化剂,并用甲基橙的光催化降解反应对所得薄膜型催化剂的活性进行了评价．实验结果表明：x（W）＝0．5％,涂覆层数为3层,在500℃焙烧1h的WO3－TiO2薄膜型光催化剂的活性最高,比纯TiO2薄膜高出96．7％．此时多孔钛片上负载的TiO2以锐钛矿和金红石两种晶形存在,表明适量W的掺入可使TiO2的相转变温度显著降低．     

TiO2／SnO2复合光催化剂的耦合效应

采用改进的 sol-gel技术制备ＴiO2/SnO2耦合型半导体光催化剂,利用ＸＲＤ、气相色谱仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素,并通过降解甲醛探讨其在空气污染治理中的作用。实验结果表明,添加20％（mol)SnO2的复合半导体光催化剂,其光催化效率比纯TiO2高一倍以上。据实验结果和粒子紧密堆积原理,提出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半导体光催化剂的光催化效率随SnO2 含量变化规律。     

TiO2/活性炭负载型光催化剂的溶胶-凝胶法合成及表征

以钛酸四丁酯为钛源,采用溶胶-凝胶法在多孔活性炭(AC)表面合成TiO2前驱体,在氮气保护下程序升温处理制得TiO2/AC负载型光催化剂.采用X射线衍射、漫反射光谱、傅里叶变换红外光谱、扫描电镜、能量色散谱和低温液氮吸附等对光催化剂晶相结构、光谱特征及表面结构进行了表征.结果表明,AC可提高TiO2分散性能,降低TiO2团聚体的尺寸,并抑制其由锐钛矿相向金红石相的转变.TiO2与AC接触界面处有Ti-O-C键生成.另外,AC的含量对TiO2的能阈结构和晶粒大小影响不大.苯酚溶液的光催化降解测试结果表明,AC负载可为TiO2提供高浓度反应环境,适宜量的负载可显著提高TiO2对有机稀溶液的光催化降解活性.对于50mg/L苯酚的光催化降解,AC的质量分数分别为5%,9%和11%时催化剂协同系数分别为1.1,1.5和1.3.循环使用7次后,AC含量为9%的催化剂对苯酚的降解率仍达95.84%.     

聚甲基三乙氧基硅烷／二氧化钛有机无机杂化材料的制备

溶胶－凝胶工艺是通过溶液在低温形成无机骨架，而广泛用于玻璃和陶瓷的制备［１～６］．在此基础上发展了有机无机杂化材料（Ｏｒｍｏｓｉｌｓ），它是在连续无规的无机网络中掺杂有机组分，形成一种性能介于有机聚合物和无机聚合物之间的新型复合材料．文献报道的有机无...     

TiO2/SiO2的制备及其光催化降解敌敌畏

二氧化钛;溶胶-凝胶法;表面复合物;TiO2/SiO2的制备及其光催化降解敌敌畏     

Synthesis of TiO2 thin film by a modified sol-gel method and properties of the prepared films for photocatalyst

PTA (peroxo titanic acid) gel was prepared by a modified sol-gel method from peroxo titanic acid using TiCl₄/ethanol/water solution as the starting material at room temperature. Physicochemical properties of heat-treated gel were characterized by IR, XRD, TG-DTA and SEM. Optimal preparing conditions were chosen to prepare anatase film for the photocatalytic degradation of methyl orange. The dip-coating technique was used to synthesis the supported anatase film on quartz glass. Photocatalytic efficiency for the degradation of methyl orange under UV irradiation was also examined. It was found that the degradation efficiency of the anatase film synthesized in this paper is higher than commercial titania P25.     

不锈钢载波钝化膜的半导体性质

运用交流阻抗法和光电化学法研究了不锈钢载波钝化膜层的半导体性质。讨论了交流阻抗测试中扰动频率的变化对Mott-Schottky曲线的影响，讨论了不锈钢载波钝化膜的n/p型、杂质施主密度和平带电位等半导体性质，同时结合光电化学法对交流阻抗测试结果进行了验证分析，实验结果认为不锈钢载波钝化膜层具有与直流钝化膜层相似的半导体性质，并通过膜层的组成结构对其半导体性质作了分析。     

Electrochemical behaviour of SiO2 sol-gel coatings on stainless steel

SiO₂ coatings onto stainless steel substrates have been prepared by sol-gel in order to study the performance and mechanism of attack in different corrosive solutions. The electrochemical behaviour of the samples has been evaluated by Electrochemical Impedance Spectroscopy using NaCl and HCl as electrolytes. Comparative tests have been performed on samples with one and two silica layers as well as on uncoated ones. SiO₂ coatings produce no important protection of stainless steels subjected to electrochemical corrosion. This behaviour may be explained by micropores and microcracks produced during the coating sintering.     

Fabrication and characterization of TiO2 photocatalytic thin film prepared from peroxo titanic acid sol

A novel sol–gel technique using the PTA (peroxo titanic acid) sol as precursor for the fabrication of TiO₂ photocatalytic thin film is introduced in this paper. The peroxo titanic acid sol was synthesized from titanyl sulfate (TiOSO₄), ammonia and peroxide solution (H₂O₂). The transparent and porous TiO₂ thin film was prepared via a sol–gel technique using PTA sol and polyethylene glycol (PEG) as precursor and template, respectively. The TiO₂ thin film samples were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometry (UV–vis), X-ray photoelectron spectrum (XPS) and thermogravimetry and differential thermal analysis (TG-DTA) technique. The PTA sol displayed amorphous TiO₂ below 100 °C. The anatase phase formed at 200 °C to 700 °C. The crystallinity of anatase phase was improved with increasing temperature. The anatase crystals on the surface of TiO₂ film were strip-like, the size being about 100 nm in length and 40 nm in diameter. Addition of PEG to the PTA sol developed porous structures in the film and changed the size and shape of the particles. The surface of the film contained Ti, O and C elements and Na element that diffused into the film from the glass substrate. The photocatalytic performance of TiO₂ film was tested for the degradation of 10 mg/L methyl orange. The degradation of methyl orange solution reached 98.9% after irradiated for 180 min under UV light. The porous TiO₂ thin film exhibited high photocatalytic activity towards degrading methyl orange.     

Polydopamine supported preparation method for solid-phase microextraction coatings on stainless steel wire

In this paper, we introduced a novel and versatile route to prepare solid-phase microextraction coatings on the chemically inert stainless steel wire. Polydopamine films can be created on metallic substrates by an oxidant-induced polymerization and subsequently support various secondary reactions to prepare functional surfaces. In the present work, polydopamine-bioactivated stainless steel wire was successfully modified by nanostructured hydroxyapatite. Extraction performance of the fiber was assessed on several polycyclic aromatic hydrocarbons in water solutions. Extraction mechanism was suggested based on the correlation of partition coefficients and LogPs. Both aqueous and solid real life samples were used to test the reliability of the solid-phase microextraction-gas chromatography method; some analytes were detected and quantified.     

Influence of crystallite structure of nanometer TiO_2 catalysts on photocatalyst reaction

25 samples of nanometer TiO2 were prepared through modifying the preparation conditions including the concentrations of Ti(SO4)2 and NH4HCO3, the pH value at the end of precipitation operation, and sintering temperature and time by methods of orthogonal design. The relationships between their catalytic activities of photocatalytic degradation of sodium dodecyl benzene sulfonate (SDBS) and the normal crystallite size, lattice-strain and X-ray diffraction intensity of 10 crystal faces were analyzed. It was discovered that the photocatalytic degradation reaction of SDBS follows first-order kinetics. Crystal faces of catalysts' (101) have greater influence than other crystal faces on the reaction. The photocatalytic reaction needs more perfect (101) crystal faces with less lattice-strain. Smaller normal crystallite size and greater specific surface area of (101) crystal face are better for increasing reaction rate. The photocatalytic reaction is mainly proceeded on the (101) crystal face, comparatively, amor     

制备方法及载体类型对Ni_2P/TiO_2催化剂加氢脱硫性能的影响

以两种类型的TiO2(锐钛矿anatase、晶须载体whiskers)为载体,分别采用程序升温还原(H2-TPR)法和溶剂热法制备Ni2P/TiO2催化剂,并用X射线衍射(XRD)、N2吸附比表面积(BET)测定、N2等温吸附脱附、CO吸附表征、X射线光电子能谱(XPS)技术、扫描电镜(SEM)对催化剂的结构和性质进行了表征。考察了不同的制备方法及不同类型TiO2载体对Ni2P/TiO2催化剂二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明,溶剂热法制备催化剂过程中,保持了TiO2晶体结构,抑制了TiPO4的形成,HDS活性高于H2-TPR法制备的催化剂;与锐钛矿TiO2为载体的催化剂相比,以晶须TiO2为载体的催化剂具有更优良的表面性质,能生成较多晶体颗粒粒径较小、分散性好的Ni2P活性相,具有更高的HDS活性。以晶须TiO2为载体,采用溶剂热法制备的Ni2P/TiO2催化剂,具有最好的加氢脱硫活性,在340℃、3.0MPa、氢油体积比为500、质量空速(WHSV)2.0h-1的条件下,二苯并噻吩转化率达到为98.2%。