Synthesis of graphene/tourmaline/TiO_2 composites with enhanced activity for photocatalytic degradation of 2-propanol

We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged state of graphene and/or by introducing an external electric field arising from tourmaline.A simple two‐step hydrothermal method was used to synthesize G/T/TiO2composites and poly(diallyldimethylammonium chloride)‐G/T/TiO2composites.In the photocatalytic degradation of2‐propanol(IPA),the catalytic activity of the composite containing negatively charged graphene was higher than of the composite containing positively charged graphene.The highest acetone evolution rate(223?mol/h)was achieved using the ternary composite with the optimum composition,i.e.,G0.5/T5/TiO2(0.5wt%graphene and5wt%tourmaline).The involvement of tourmaline and graphene in the composite is believed to facilitate the separation and transportation of electrons and holes photogenerated in TiO2.This synergetic effect could account for the enhanced photocatalytic activity of the G/T/TiO2composite.A mechanistic study indicated that O2??radicals and holes were the main reactive oxygen species in photocatalytic degradation of IPA.

TiO_(2)-WS_(2)异质结的制备及其在医药废水处理中的应用

通过水热法原位合成了TiO_(2)-WS_(2)异质结样品,采用XRD、Raman、XPS、SEM、TEM、HR-TEM、BET、UVVis DRS、PL和EIS技术对样品的结构组成和光电性质进行分析,以环丙沙星为目标污染物,对样品的光降解性能进行评价。研究结果表明:TiO_(2)-WS_(2)异质结样品能够提高光生载流子的分离效率,使得TiO_(2)-WS_(2)样品在光催化降解环丙沙星时展现出了优异的活性,经过120 min光照后,对环丙沙星的达到了94.8%,较TiO_(2)样品和WS_(2)样品降解率明显提高,自由基捕获实验表明·OH和·O_(2)-为TiO_(2)-WS_(2)样品光催化降解环丙沙星过程中的主要活性物种。

Accelerating photocatalytic hydrogen evolution and pollutant degradation by coupling organic co-catalysts with TiO_2

Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of highly active co-catalysts has proven to be a promising approach for improving photocatalytic activity. Thus far, the most developed co-catalysts for semiconductor-based photocatalysis are inorganic materials;the employment of a specific organic molecule as a co-catalyst for photocatalytic hydrogen evolution and pollutant photodegradation is rare and still remains a challenging task. Herein, we report on the use of an organic molecule, oxamide (OA), as a novel co-catalyst to enhance electron- hole separation, photocatalytic H2 evolution, and dye degradation over TiO2 nanosheets. OA-modified TiO2 samples were prepared by a wet chemical route and demonstrated improved light absorption in the visible-light region and more efficient charge transport. The photocatalytic performance of H2 evolution from water splitting and rhodamine B (RhB) degradation for an optimal OA-modified TiO2 photocatalyst reached 2.37 mmol g^–1 h^–1 and 1.43 × 10^-2 min^-1, respectively, which were 2.4 and 3.8 times higher than those of pristine TiO2, respectively. A possible mechanism is proposed, in which the specific π-conjugated structure of OA is suggested to play a key role in the enhancement of the charge transfer and catalytic capability of TiO2. This work may provide advanced insight into the development of a variety of metal-free organic molecules as functional co-catalysts for improved solar-to-fuel conversion and environmental remediation.

Preparation of TiO_2/SiO_2 Aerogels by Non-supercritical Drying Method and Their Photocatalytic Activity for Degradation of Pyridine

TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XRD and so on. The results indicate that the BET surface area of TiO2/SiO2 aerogels calcined at 550℃ which consisted of anatase structure of TiO2 with narrow distribution pores of 5-25 nm is as high as 357.89 m2·g-1. For the photocatalytic degradation of pyridine, the catalytic activities of TiO2/SiO2 aerogels are much higher than that of TiO2 powder. The photocatalytic activity of TiO2/SiO2 aerogels calcined at 800℃ is the optimum. The higher the content of SiO2, the higher the photocatalytic activity of TiO2/SiO2 aerogels. The cost for preparation of the aerogels is greatly reduced by using non-supercritical drying method, and the aerogels are hopefully applied in the treatment of industrial waste water such as coking effluent treatment.

Absorption and Photocataly tic Degradation of Machine Oil by Exfoliated Graphite-Supported Nanometer TiO2 Material

By loading nanometer anatase onto exfoliated graphite with the sol-gel method, exfoliated graphite-TiO2 composite （EG-TiO2） can be prepared, which can adsorb oil and can also degrade oil. In a technologic condition for preparing EG-TiO2, the impregnated number of times is the most important factor to influence oil-adsorbing capability, that is, when the impregnated number of times increases, the amount of saturation-adsorbed oil decreases. The study of EG-TiO2 photocatalytic degradation of machine oil based on the weight-loss method and infrared spectrum method indicates that EG-TiO2 has obvious effect of photocatalytic degradation for machine oil. Its performance is superior to pure nanometer TiO2 powder because nanometer TiO2 in EG-TiO2 has three-dimension laminar structure and comparatively high adsorption capability.

Synthesis of thiol-functionalized TiO_2 nanocomposite and photocatalytic degradation for PAH under visible light irradiation

In this paper, a thiol-functionalized nanophotocatalyst MPTES/TiO2 was first synthesized by one-pot method using P123 as a template. X-ray diffraction confirms the complete anatase crystalline of thiol-functionalized TiO2, N2 adsorption-desorption isotherm demonstrated that these materials possess high surface area and mesoporous structure. The results of XPS show that MPTES has been successfully polymerized in mesoporous structured TiO2. The photodegradation of phenanthrene （PHE） was investigated under visible light irradiation （λ 〉 420 nm） to evaluate the photocatalytic activity of these materials. Based the experiment results of GC-Mass analysis, a possible mechanism was proposed.

Photocatalytic Activity of TiO_2 Coating on Natural Feather Zeolite in Degradation of Orthomonochlorphenol

Ti02 coatings on natural feather zeolite are respectively prepared by a collosol （Sol-gel） method and two powder coating methods with deionizod water or dehydrated ethanol as a dispersant. During degradation of orthomono- chlorphenol solutions by ultraviolet, the strong adsorption capability of the zeolite results in increased concentration of substrate on its surface. The Ti（h film coated on feather zeolite further enhances the photocatalytic activity. The TiO~ film on the zeolite prepared by the Sol-gel method is found more effective as a catalyst than that by two powder coating methods.

TiO_2光催化反应及其在废水处理中的应用

ＴｉＯ２多相光催化能利用太阳能有效降解多种对环境有害的污染物，使有害物质矿化为ＣＯ２、Ｈ２Ｏ及其它无机小分子物质。本文综述了ＴｉＯ２光催化的机理，提高光催化能力的途径，多种具有代表性污染物的光催化降解处理方法，以及目前尚存在的一些问题，扼要介绍了近年来ＴｉＯ２光催化反应及其在废水处理中应用的研究进展及应用前景。

附载TiO_2光催化降解咪蚜胺农药

以主波长３６５ｎｍ的黑炽荧光灯为光源，研究了由ＣＭＣ－Ｎａ附载ＴｉＯ２光催化降解咪蚜胺农药的过程。结果表明，咪蚜胺农药在３×８Ｗ黑炽荧光灯照射下，经附载ＴｉＯ２作用３ｈ后可降解５０％以上，其光解可用假一级动力学方程表示。对于加ＣＭＣ－Ｎａ附载的ＴｉＯ２玻板，ＴｉＯ２不易脱落，经多次使用其光催化活性不变，而直接附载的ＴｉＯ２却有流失现象发生。另外，初探了以自然光为光源催化降解咪蚜胺农药的可行性。

纳米TiO_2对农药的降解

利用过氧络合物热分解法制备了锐钛矿型纳米TiO2微粉。研究了锐钛矿纳米TiO2对农药的光催化降解。结果显示对于顺反氯氰菊酯乳液以及多肼悬浮剂药物降解效果较好,但对于复杂的酸类杀菌剂则难以彻底降解。利用纳米TiO2材料对农药进行光催化降解,为防治农药对环境的污染以及消除农药残留提供了一个新途径。

TiO_2纳米粒子气固相光催化降解乙烯初探

该文对TiO2纳米粒子气固光催化降解果蔬贮藏环境乙烯技术进行了初步研究。采用溶胶-凝胶法制备的纳米TiO2薄膜作光催化剂,利用自行设计的气固光催化实验系统,研究了乙烯浓度、紫外光作用时间对光催化降解反应的影响,探讨了乙烯的光催化降解的动力学。结果显示:该研究所制备的TiO2锐钛矿型含量为48.766%,比表面积为47.186m2/g,具有良好的光催化性能;光催化降解乙烯比直接紫外线光降解效果显著,光照10min时光催化乙烯降解率比直接紫外线光降解提高23.76%;乙烯的降解率随着其浓度的增加而降低;乙烯的光催化降解的动力学可以用Langmuir-Hinshelwood动力学方程加以描述。

复合涂料中纳米TiO_2降解污染物和抗菌性能研究

利用纳米尺度分散TiO2 的光催化作用 ,研究纳米TiO2 光催化剂复合涂料降解空气中氨气、甲醛和苯类化合物及抗菌防霉的性能。测试结果表明 :该涂料对密闭空间内的甲醛、氨气和苯类等化合物的降解效率均可达到 90 %以上 ,对多种有害细菌均具有杀菌彻底性和长效性 ,并且其光催化作用可以摆脱光源条件的严格限制。并探讨了纳米TiO2

纳米TiO_2光催化降解有机物的机理及其影响因素的研究

对纳米TiO2 光催化降解水中有机物的机理进行了研究 ,并对溴苯酚降解为目标反应 ,系统分析了紫外光强度、TiO2 浓度、温度、溶液的pH值以及杂质等对光催化降解为溴苯酚程度的影响。优化这些因素可以提高纳米TiO2 光催化降解率。

溶胶液浓度和镀膜层数对TiO_2薄膜光催化活性的影响

作者用sol gel法制备了不同浓度、不同层数的锐钛矿纳米TiO2 薄膜。利用薄膜对亚甲兰溶液的光催化降解作用 ,研究了溶胶液浓度、镀膜层数及两者间的相互关系对薄膜光催化性能的影响。发现并非浓度越大、镀膜层数越多、膜的光催化性能越好。不同浓度的溶胶液匀有各自催化性能最佳的膜层数 ,超过该层数后膜的催化性能降低。浓度大的膜在层数较少时催化性能好 ,浓度小的膜随层数增加 。

负载型TiO_2催化剂上光催化降解NH_3的研究

用Sol Gel法制备负载型TiO2 催化剂并进行了氨气的光催化降解研究 ,考察了负载次数。

SO_4^(2-)/TiO_2-SiO_2的制备及光催化降解苯酚

Ultra fine SO 2- 4/TiO 2-SiO 2 complex catalysts were synthesized by the one-step calcination method,which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts are characterized by XRDIRTDA and BET. Different preparation factors were discussed.The catalysts consisting of SO 2- 43.4% and TiO 2∶SiO 2=1∶6 showed excellent reaction activity and stability for the photocatalytic degradation of phenol.Controlling calcination temperature and time (450℃,2h) could avoid or diminish the formation of Ti-O-Si bond and obtain higher V g and better dispersivity of TiO 2 on the surface of SiO 2.The kinetic study on photocatalytic degradation of phenol with the complex catalysts in a suspension system under 40W UV-lamp showed that apparent rate constant k conformed to a zero-order kinetic model at initial concentration <100mg·L -1 and increased with increasing pH value of phenol solution up to pH=12.When pH=10,k=3.32×10 -1 mg·L -1 ·min -1 . Solar photocatalytic experiment also gave good results.

非整比纳米TiO_(2-X)膜光催化降解水中微量卤代烃

采用溶胶 -凝胶法在石英板上经可控热处理制备出非整比 Ti O2 - X膜 ,膜中晶粒具有纳米结构特征 .在臭氧氧化条件下用无机非整比纳米 Ti O2 - X膜光催化氧化饮用水中微量卤代烃 ,结果表明 ,该方法可使卤代烃的降解率在 99.9%以上 ,适用于饮用水的深度处理 .

TiO_2粉末催化剂光催化降解室内空气中有机污染物

本文制备了一系列ＴｉＯ２粉末催化剂，用光催化法降解室内空气中各种微量有机污染物，最终降解率接近１００％．考察了晶型对光催化剂性能的影响，结果表明，锐钛矿型ＴｉＯ２的催化性能最好．最后。

rGO改性TiO_2薄膜的制备及光催化性能

氧化石墨烯-二氧化钛(GO-TiO_2)前驱体溶胶经浸渍-提拉成薄膜,再经热处理、紫外辐照还原得到还原氧化石墨烯-二氧化钛(rGO-TiO_2)薄膜.利用XRD、Raman、SEM对薄膜进行表征分析.通过光催化还原Ag+以及光催化降解甲基橙研究GO加入量对rGO-TiO_2薄膜光催化性能的影响;并将光催化还原Ag+后的薄膜直接用于降解甲基橙.结果表明:薄膜中TiO_2的晶相为锐钛矿相与金红石相的混合晶相,GO部分被还原为rGO;薄膜表面平整,片状rGO均匀镶嵌其中;当GO质量分数为1.0%和1.5%时,rGO-TiO_2薄膜的光催化性能接近,光催化还原Ag+的效率为93%左右,光催化降解甲基橙的效率为92%左右;光催化还原Ag+后的薄膜直接用来降解甲基橙,其降解效率明显提高.

纳米TiO_2光催化活性及其应用

纳米 Ti O2 作为光催化环境材料能有效降解多种对环境有害的污染物 ,使有害物质矿化为 CO2 ,H2 O及其他无机小分子物质 ,因此可用于废水处理、空气净化以及杀菌除臭 .本文综述了纳米级 Ti O2 的制备及其光催化的机理 ,扼要介绍了纳米 Ti O2 光催化反应在农药、医药、催化剂 (化工 )、环境工程等各方面的研究进展及应用前景 .