Charge Transfer in Photocatalytic Systems: V and Mo Doped TiO2/Ti Electrodes

Charge transfer between the redox couples in solution and the electrodes obtained by surface doping of TiO₂ either by vanadium or by molybdenum have been investigated by electrochemical methods. In both cases the doping metal ions form at the electrode/solution interface surface states which are able to mediate the transfer of electrons between the conduction band of TiO₂ and the redox species in solution.     

过渡金属掺杂二氧化钛光催化性能的研究

采用浸渍法制备了过渡金属掺杂的光催化剂MOx/TiO2(M=Cr、Mn、Fe、CO、Ni、Cu)．以乙酸的光催化氧化降解反应为探针，研究了催化剂的光催化性能．研究结果表明，经过渡金属掺杂改性的二氧化钛，光催化性能都有所提高．掺杂量有一个最佳值，在最佳掺杂量时，催化剂光催化性能的提高程度与对应金属氧化物的生成焓有很好的一致性，还发现光催化性能与过渡金属离子稳定氧化态的电子亲和势与离子半径的比值间呈现火山型关系曲线．     

金属离子掺杂二氧化钛及水体光催化脱氮研究

采用溶胶-凝胶法制备了掺杂Ce^3＋、La^3＋、Ag^＋、Fe^3＋的TiO2光催化剂，以考察其薄膜和粉体形式对水中无机氮的光催化去除效果和活性．用所制备的催化剂对含氨氮-亚硝酸氮的混合液进行了光催化脱氮研究．本文利用UV—Vis吸收光谱、XRD和TEM对催化剂进行了表征．同时，对影响TiO2光催化效率的因素：如掺杂金属离子的种类、浓度、涂膜层数、反应液中有无Fe^2＋、不锈钢和玻璃载体、反应器的构型等进行了探讨，并对今后的研究进行展望．经过2h紫外光照射反应，实验最佳脱氮效果：金属离子掺杂TiO2薄膜型催化剂总氮去除率在30％左右，金属离子掺杂粉末型催化剂光催化最高总氮去除率可达41．7％．     

过渡金属离子掺杂改性TiO2研究进展

综述了近年来国内外利用过渡金属离子掺杂改性TiO2的光催化性能和光响应范围、掺杂机理及掺杂模型；分析了制备方法、掺杂金属离子种类、浓度对TiO2光催化性能的影响；归纳总结了针对光催化研究目前的现状和存在的问题讨论了今后的研究方向。     

掺Ag,Ni对TiO2气相光催化活性的影响

采用溶胶-凝胶法制备了以活性炭为载体的负载型Ag/TiO2及Ni/TiO2光催化剂,以气相中甲苯降解反应考察了两种催化剂的活性随金属离子掺杂量的变化. 用透射电镜、X射线衍射及荧光光谱对掺杂催化剂进行了表征. 结果表明,经Ag, Ni掺杂后,Ag/TiO2和Ni/TiO2两种催化剂的催化活性均有不同程度的提高,且Ni/TiO2优于Ag/TiO2. 两种催化剂的最佳掺杂量均为0.4%. 根据表征及实验结果分析了金属离子不同掺杂量影响TiO2光催化活性的机理.     

影响TiO2从锐钛型转变为金红石型的相变因素的研究

考察了V2O5、MoO3、醋酸及钾盐对TiO2由锐钛型向金红石型转变的影响，在相同条件下，V2O5对转化的促进作用优于MoO3，并且转化率随V2O5用量的增加而增大，适当使用醋酸和钾盐，也可促进TiO2由锐钛型到金红石型的相变过程。     

Photocatalytic and Photoelectrocatalytic Performance of 1% Pt Doped TiO2 for the Detoxification of Water

The degradation of formic acid (HCOOH), FA (a surrogate contaminant) using titanium dioxide (TiO₂) and 1% Pt doped TiO₂ electrodes, prepared by sol—gel methods, was investigated in a photoelectrocatalytic (PEC) system in order to determine the effect of Pt doping on the oxidation potential of TiO₂. Pt doping shifts the position of band edge and therefore the direct and indirect oxidation potentials of TiO₂ in PEC systems. As a result, the degradation of formic acid via the generation of hydrogen peroxide production on 1%Pt—TiO₂ electrodes was much better than that on non-doped electrodes. The degradation of HCOOH was also examined with respect to the faradaic efficiency of this process. It was found that the 1%Pt—TiO₂ photoanode had a 30% higher efficiency than that of non-doped TiO₂ photoanodes.     

金属掺杂TiO_2纳米复合氧化物的光催化性能研究

文章针对水污染处理,对水热法合成金属掺杂TiO2纳米复nanometer合氧化物得到的光催化剂,通过XRD、SEM和UV-vis DRS对催化剂的结构进行表征,及光催化性能进行研究,为开发高效、廉价的实用水污染有机物降解催化剂创造条件。     

不同离子掺杂TiO_2薄膜及光催化活性研究

采用溶胶-凝胶法分别制备了掺杂Fe^3＋、Cu^2＋、Zn^2＋、Ce^3＋和La^3＋5种不同离子的纳米级TiO2薄膜,使用TiO2薄膜对亚甲基蓝溶液进行光催化试验。研究表明,在5种掺杂离子中,其La^3＋的掺杂效果最好,当La^3＋的适宜含量为1.8%（质量分数）时,掺杂与未掺杂的XRD图谱基本一致;掺入La^3＋离子使得TiO2的晶粒变小,可抑制晶相向金红石相转变;随着焙烧温度的升高TiO2晶粒逐渐变大,温度为700℃时,其粒径为27.6nm,TiO2为混合晶型（锐钛矿型和金红石型）,其活性最高。     

Different Effects of Fluoride Surface Modification on the Photocatalytic Oxidation of Phenol in Anatase and Rutile TiO2 Suspensions

The effect of calcination temperature on the photocatalytic degradation of phenol with aqueous suspensions of synthetic anatase and rutile TiO₂ under UV light irradiation (λ > 320 nm), was studied in the absence and presence of NaF. The presence of fluoride accelerates the degradation of phenol in anatase TiO₂, with this positive effect increasing at first, before declining with increasing calcined temperature. A negative effect of fluoride was observed for all the rutile TiO₂ suspensions. The selectivity of catechol increased in the presence of fluoride in both anatase and rutile TiO₂ suspensions.     

Facile Synthesis of Fluorine Doped Rutile TiO2 Nanorod Arrays for Photocatalytic Removal of Formaldehyde

Catalysis Letters - It is crucial to explore a facile synthesis of rutile TiO2 nanorods anchored at carbon cloth at low temperature for applicable air purifier. Herein, antler-like TiO2 rectangular...     

Influence of Rutile and Anatase TiO2 Nanoparticles on Polyethylene Properties

Nanocomposites from polyethylene and TiO₂ with different shape and size were prepared by direct mixing and masterbatch dilution, respectively. The mechanical properties of nanocomposites were determined and discussed in relation to the nanofiller dispersion. Moreover, the morphological aspects of polyethylene with and without nanofiller were revealed by means of SEM and WAXD. A better dispersion of the nanoparticles and increased mechanical properties were observed in the case of the masterbatch method. No important differences in mechanical and morphological characteristics of anatase and rutile containing polyethylene composites were observed, except a higher increase of the elastic modulus in case of anatase-containing composites.     

Ag掺杂TiO2纳米薄膜光催化活性研究进展

TiO2在光催化和光电转化领域拥有十分广阔的应用前景,近几年来备受研究人员广泛关注.本文综述了TiO2光催化反应机理以及掺银TiO2纳米薄膜的制备方法,其中包括溶胶凝胶法、微乳液法、电弧溅射法、阳极氧化法以及表面化学反应等.主要讨论了Ag单掺杂和Ag与其他元素共掺杂的TiO2纳米薄膜光催化活性的研究进展,并对二者进行比较,展望了其发展方向.共掺杂TiO2纳米薄膜因比单掺杂薄膜具有更优异的光催化性能,是未来的主要研究方向之一.     

锐钛矿型纳米TiO2的制备及光催化性能研究

采用水热法将钛酸四丁酯(TNB)在碱性和酸性条件下分步进行反应，制备了锐钛矿型纳米二氧化钛(TiO2)粉体，通过差热-热重分析(DSC-TG)、X射线衍射(XRD)、透射电镜(TEM)等方法对粉体进行表征，以及用重铬酸根离子(Cr2O7^2-)还原探针反应对制得的粉体的光催化性能进行测试，结果表明所得粉体粒度小于20nm，并具有良好的光催化性。其中300℃处理后颗粒平均粒径为7nm，二氧化钛晶型发育完整。     

元素掺杂锐钛矿型TiO_2改善光催化活性研究进展

二氧化钛,白色无毒两性氧化物,被广泛应用于涂料、塑料、橡胶、化妆品等工业。而对锐钛矿相TiO_2进行掺杂,使它的电子结构和光学性质发生改变,可拓展其在光催化领域的应用。本文综述了自20世纪70年代起,以非金属元素掺杂TiO_2为起点,学者们开展的更广泛的研究情况进展,并对掺杂原理以及引起的光催化活性改变进行分析。     

P-25 TiO2的结构相变和光催化活性

采用XRD、TEM、BET和UV-Vis漫反射吸收方法对各种温度焙烧的P-25 TiO2进行了表征,利用光催化降解苯酚的反应,研究了焙烧温度对P-25 TiO2晶相结构的影响以及晶相结构与其光催化活性之间的关系。结果表明,热处理可调变TiO2的晶相结构。500℃焙烧时,TiO2为锐钛矿与金红石质量比约70：30的混晶,其光催化降解苯酚活性最高。P-25 TiO2光催化活性的高低与其晶相结构密切相关。     

Synthesis and Characterization of Rutile TiO2 Nanopowders Doped with Iron Ions

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO₂ into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence.     

掺N纳米ZnO/TiO2复合粉体的光催化性能

以Ti(SO4)2和Zn(NO3)2为原料,CO(NH2)2为沉淀剂,采用均匀沉淀法制备了掺N和不同质量分数ZnO掺杂的纳米TiO2复合粉体,通过XRD、XPS、TEM等进行了表征,并以甲基橙水溶液为底物,测定了其光催化性能。结果表明,掺杂产生了Ti—O—Zn和Ti—O—N键,使复合粉体的激发波段从紫外光波段扩展到可见光波段,催化活性大大提高,其中w(ZnO)=2%时,复合粉体太阳光催化性能最高,太阳光照射6 h,甲基橙降解率达到98.4%,重复使用6次后,降解率仍达到94.2%。     

低温制备Fe-TiO2及其可见光催化性能研究

采用大量水体系溶胶-凝胶方法在低温下制备了掺杂铁的二氧化钛纳米材料(Fe-TiO2),通过XRD、XPS、SEM、UV-Vis对样品进行了结构、形貌以及光化学方面的表征,研究了铁掺杂浓度对样品结构和性能的影响。结果表明,低温下合成的样品主要以锐钛矿型存在,结合有少量板钛矿型。掺杂1%的Fe-TiO2具有最大的吸收带红移,在室内具有最好的对甲基橙光催化性能。主要认为铁的掺杂抑制了电子和空穴的复合并且增强了其在可见光区的吸收。