TiO2介孔光催化剂的制备研究进展

介孔TiO2是一种新型高效的光催化剂，综述了介孔TiO2的各种制备方法及其相关材料性能和在光催化降解方面的应用。分析了目前介孔TiO2材料合成和应用中存在的问题，展望了该领域的研究前景。     

TiO2介孔材料合成及应用

TiO2介孔材料因其在光催化、催化剂载体、传感器、电化学器件等方面具有种种潜在的用途而备受关注，已经成为材料科学一个崭新的研究方向。综述了介孔TiO2的合成方法及应用等方面的研究成果。     

模板法制备TiO2介孔材料的研究进展

TiO2介孔材料在催化、吸附及分离等领域具有十分重要的应用,是当今介孔材料研究的热点之一。本文综述了介孔材料的分类,概述了模板法制备TiO2介孔材料的机理及不同类型的模板剂在TiO2介孔材料制备中的应用,指出了模板剂脱除过程中存在的问题,并对介孔材料的研究和应用前景进行了展望。     

Ce掺杂的锐钛矿型纳米介孔TiO2(Ce-MTiO2)的制备及其光催化降解活性研究

采用模板技术通过直接掺杂的方式合成了稀土元素Ce掺杂的锐钛矿型纳米介孔TiO2.在500 W高压汞灯照射下,研究了低浓度有机磷农药敌敌畏、氧化乐果的光催化降解,研究结果表明,该催化剂具有很高的光催化活性和稳定性,且能够重复使用.对催化剂的N2吸附、XRD、UV-Vis、FT-IR表征结果表明,该材料为高度有序、高比表面积的纯锐钛矿晶型的介孔二氧化钛材料(Ce-MTiO2).该催化剂具有很高的光催化活性可能与稀土元素Ce的电子结构、锐钛矿纳米晶、介孔结构和高比表面积有密切关系.     

复合模板剂下制得介孔TiO2光催化活性的研究

以吐温-80（Tween-80）和司班-80（Span-80）为复合模板剂，采用溶胶-凝胶（sol-gel）工艺制得介孔TiO2。通过对甲基橙溶液进行光催化降解试验表明：模板剂的种类与用量、光照距离和甲基橙溶液的原始浓度等因素对所制得介孔TiO2试样的光催化活性产生明显的影响。实验结果证明，本研究所得介孔TiO2材料具有较高的光催化活性，500℃下煅烧5h制备的样品在2．5h内可使浓度为0．02g／L的甲基橙溶液降解率达到94．7％，明显高于市售纳米TiO2粉体的降解率78．1％；通过X-ray衍射分析获知所制TiO2为锐钛矿型。     

静电组装法制备介孔TiO_2

以TiCl4和(NH4)6Mo7O24·4H2O为原料,先通过水解、静电自组装和焙烧得到TiO2/MoO3,再用NaOH溶液溶解得到介孔TiO2。用X射线粉末衍射(XRD)、透射电镜(TEM)、X射线能量色散仪(EDX)、紫外-可见漫反射光谱(UV-DRS)和比表面及孔隙度分析仪(ASAP)对该材料进行表征,合成的介孔TiO2BET比表面积为241 m2/g,平均孔直径为3.5nm。通过光催化降解甲基橙实验,发现介孔TiO2具有较高光催化活性。     

介孔TiO2的合成及其光催化性能研究进展

介孔TiO2材料由于其优越的孔道结构、大比表面积,良好的吸附能力及易回收等特点,在光催化降解有机污染物等方面表现出优异的性能,在能源、环保、化工等领域都具有十分重要的科学和实际意义。从合成方法、光催化性能及其影响因素、应用性等方面对近年来国内外介孔TiO2的研究状况进行了详细阐述,并在此基础上分析比较了不同合成方法的优缺点,及今后的发展方向。     

La掺杂TiO2介孔微球的超声水热合成和光催化性能

以钛酸四丁酯为钛源、硝酸镧为镧源、十二胺为模板剂,采用超声?水热法合成了La3+掺杂介孔TiO2微球,并利用XRD、XPS、TEM、BET、UV-Vis、IR、FL等手段表征了材料的结构、形貌、比表面积、孔径分布及光学性能.研究结果表明,适量La3+离子掺杂不仅能使介孔TiO2晶粒细化,比表面积增大,荧光强度减弱.La3+/TiO2的光吸收边红移,并具有比商业P25更好的光催化活性,其中介孔La3+/TiO2(2.0at%)的比表面积和平均孔径分别为132.7 m2/g和8.67 nm,光催化降解初始浓度为40 mg/L的亚甲基蓝溶液120 min时,其降解率达到98.5%,表现出最强的光降解能力.     

胶原纤维为模板TiO_2、La_x/TiO_2纳米纤维的制备、表征及光催化活性研究

以胶原纤维为模板分别负载钛(Ti4+)或钛(Ti4+)和镧(La3+),经高温煅烧制得介孔TiO2和La x/TiO2纳米纤维。通过场发射扫描电镜(FESEM)、N2吸附-脱附等温线、X射线衍射(XRD)、分子荧光光谱(PL)和紫外-可见吸收光谱(UV-Vis)等对这2类纳米纤维的结构和物理性能进行了表征。结果表明胶原纤维的纤维状结构能被较好地保留在TiO2和La x/TiO2纳米纤维中。TiO2和La x/TiO2纳米纤维的N2吸附-脱附等温线属于典型的Ⅳ型,表明其具有介孔结构。XRD分析表明,La3+的掺杂减小了TiO2的晶粒尺寸。与Degussa P25相比,介孔TiO2和La x/TiO2(x≤0.02)纳米纤维的紫外-可见吸收光谱红移,分子荧光光谱强度明显减弱。以孔雀石绿的光催化降解为模型反应,在可见光和紫外光激发下,介孔TiO2和La x/TiO2纳米纤维的光催化活性均高于Degussa P25。此外,La x/TiO2在可见光激发下的光催化活性高于未掺杂的TiO2纳米纤维。     

介孔TiO2可见光改性研究

介孔TiO2作为催化剂降解污水中有机污染物颇有发展前景,目前主要的研究工作是使TiO2的光响应波长由紫外光向可见光发展.系统介绍了TiO2的光催化降解有机污染物的原理及掺杂改性机理,并指出光催化领域现今存在的问题以及发展趋势.     

TiO2/ACF光催化再生复合材料的研究进展

总结近年来在TiO2与活性碳纤维复合光催化剂的合成方法、结构与性能,及对室内挥发性有机物光催化降解方面的研究,分析TiO2/ACF复合光催化剂对有机物吸附、富集、光催化、原位再生的过程,探讨活性碳纤维吸附材料对提高TiO2光催化剂量子产率的作用机制,认为低浓度污染物在催化剂表面的吸脱附速率提高是TiO2/ACF复合光催化剂具有较高降解能力的关健因素.     

A new submerged membrane photocatalysis reactor (SMPR) for fulvic acid removal using a nano-structured photocatalyst

The study focuses on the degradation of fulvic acid by nano-structured TiO2 in a submerged membrane photocatalysis reactor (SMPR). It has been demonstrated that the composite TiO2 photocatalyst could be automatically settled due to its gravity and then be easily separated by MF membrane. In addition, it was more efficient to maintain high flux of membranes than that of commercial TiO2 P25. The paper describes the effects of operational parameters on the photocatalytic degradation of fulvic acid in SMPR. It was found that the photocatalyst at 0.5 g/L and airflow at 0.06 m3/h were the optimal condition for the removal of fulvic acid (FA) and the FA degradation rate was higher at acidic condition than that at alkalinous media. In order to compare the effects of different filtration duration on permeate flux rate of MF, P25 powder and nano-structured TiO2 were employed. According to the experiments, the permeate flux rate of MF is improved and thus the membrane fouling phenomenon is reduced with the addition of nano-structured TiO2 catalyst. Therefore, the submerged membrane photocatalysis reactor can be potentially applied in photocatalytic oxidation process during drinking water treatment.     

新型TiO2光催化复合分离膜研究进展

TiO2光催化复合分离膜是近几年出现的一种集光催化和膜分离作用于一体的新型多功能复合膜,多用于水处理中.将光催化剂TiO2负载于膜表面或者内嵌于膜中,制备成光催化复合分离膜,不仅解决了TiO2的回收问题,且能在一定程度上缓解或者消除膜污染问题;在发挥光催化和膜分离作用的同时,还能产生一系列的协同作用,以加强污染物的处理...     

TiO2@SBA-15的合成及其光解性能

以水热沉积法在介孔SBA-15上固载TiO2纳米粒子制得光催化剂TiO2@SBA-15,探讨了TiO2负载量对催化效果的影响.以包括N2吸附-脱附、紫外漫反射光谱(DRS)等手段在内的多种技术手段表征了催化剂的结构.研究结果表明适宜负载量的锐钛矿晶型TiO2纳米粒子可均匀分散在载体SBA-15上,N2吸附-脱附进一步表明载体介孔结构得以保持.适宜TiO2负载量的催化剂20 mg紫外光照25 min可将100 mL的10 mg·L-1亚甲基蓝降解完全.     

Photocatalytic degradation of mixed pollutants in aqueous wastewater using mesoporous 2D/2D TiO2(B)-BiOBr heterojunction

There are multiple contaminants in practical wastewater;and the photodegradation of mixed pollutants is a challenge in the field of photocatalysis.Herein,we design a mesoporous 2D/2D TiO2(B)-BiOBr hetero-junction photocatalyst for the photodegradation of mixed pollutants.Such a coupling structure results in an enhancement in the disconnection of photoexcited carriers,and the increase of absorption and reaction sites.The 2D/2D TiO2(B)-BiOBr demonstrates outstanding photocatalytic activity for photode-grading rhodamine B(RhB),methyl orange(MO),tetracycline hydrochloride(TCH),and bisphenol A(BPA)simultaneously under visible light,which is 4.7.1.4,23 and 16.4 times as high as that of original BiOBr,respectively.Our work represents a possible solution to devise promising and efficient photocatalysts for the treatment of practical wastewater in the near future.     

负载型TiO2光催化剂对几种有机物的降解实验研究

以斜发沸石作为载体,用溶胶-凝胶法制备了TiO2/沸石光催化剂.利用IR、XRD 等手段对其进行了表征.以太阳光为光源,光解率为评价指标,对几种不同结构有机物的降解实验表明,TiO2/沸石光催化剂对有机物的降解有明显的选择性.光催化效果在反应初期主要依靠沸石的吸附作用,最终的光解率由有机物的分子量及所带电荷决定,有机物的浓度越大,光解率越低.     

Cyclic performance and photo-induced crystalline growth of nanostructured AgI/TiO2 visible light photocatalyst

Nanostructured AgI/TiO2 visible light photocatalyst was prepared with AgNO3, KI, and Ti(OBu)4 as precursors. The photocatalyst was used repeatedly to degrade methylene blue and methyl orange in water with visible light irradiation. Though a high photocatalytic efficiency was observed for the photocatalyst in the first cycle, the photocatalytic efficiency was found to decrease dramatically in subsequent cycles. X-ray diffraction and SEM analyses revealed an obvious crystalline growth of AgI in AgI/TiO2 nanocomposite after photocatalysis or visible light irradiation. It was proposed that photo-induced crystalline growth had occurred to AgI in the course of photocatalysis and resulted in dramatic decrease in the photocatalytic efficiency of the photocatalyst. Photo-induced crystalline growth may be a limiting factor for the lifetime of photocatalysts and should be examined as an important aspect of photostability when new photocatalysts are developed.     

Different methods in TiO2 photodegradation mechanism studies: gaseous and TiO2-adsorbed phases

The development of photocatalysis processes offers a significant number of perspectives especially in gaseous phase depollution. It is proved that the photo-oxidizing properties of photocatalyst (TiO(2)) activated by UV plays an important role in the degradation of volatile organic compounds (VOC). Heterogeneous photocatalysis is based on the absorption of UV radiations by TiO(2). This phenomenon leads to the degradation and the oxidation of the compounds, according to a mechanism that associates the pollutant's adsorption on the photocatalyst and radical degradation reactions. The main objective of the study is the understanding of the TiO(2)-photocatalysis phenomenon including gaseous and adsorbed phase mechanisms. Results obtained with three different apparatus are compared; gaseous phases are analysed and mechanisms at the gaseous phase/photocatalyst interface are identified. This study leads to improve understanding of various mechanisms during pollutant photodegradation: adsorption of pollutants on TiO(2) first takes place, then desorption and/or photodegradation, and finally, desorption of degradation products on TiO(2). The association of analytical methods and different processes makes the determination of all parameters that affect the photocatalytic process possible. Mastering these parameters is fundamental for the design and construction of industrial size reactors that aim to purify the atmosphere.     

模板法制备介孔TiO2光催化剂的研究进展

介绍了各样模板及相关介孔制备体系,包含表面活性剂模板制备,非表面活性剂模板制备,其它模板制备及非模板制备。结果显示介孔结构可以很好的提高纳米TiO2的光催化活性,虽然在少数例子中介孔结构对光催化活性产生的影响很小或是没有影响。重点论述了上述研究方法的原理、优缺点和在改变TiO2性能中的应用,以及这些方法相结合所取得的一些研究进展;并指出这些方法在TiO2光催化剂的研究中发挥的重要作用。