载银纳米二氧化钛对聚丙烯结晶性能影响

熔融挤出制备载银纳米二氧化钛(TiO2/Ag+)/聚丙烯(PP)复合材料,采用差示扫描量热仪研究纳米(TiO2/Ag+)对PP结晶性能的影响。结果表明:少量纳米TiO2/Ag对PP有成核促进作用,提高了结晶速率,使结晶度增大;当纳米TiO2/Ag十质量份数超过1%时,PP结晶陛减弱,甚至起一定的抑制作用;纳米TiO2/Ag+能提高PP结晶温度,而对PP熔融温度影响不大。     

Synthesis and Morphological Study of Nanoparticles Ag/TiO2 Ceramic and Bactericidal Investigation of Polypropylene-Ag/TiO2 Composite

Antibacterial ceramic consisting silver nanoparticles in TiO₂ (rutile phase) particles were prepared via the chemical deposition route. Structure of synthesized ceramic was characterized using different methods of spectroscopies including; X-ray diffraction (XRD), TEM, and scanning probe microscopy (SPM). The results show that very fine silver particles were loaded on the titania dispersedly and also no crystalline change happened in the TiO₂ structure. In order to preparation of antibacterial composite, ceramic was compounded into polypropylene using a Hakke internal mixer in optimized conditions. Morphology of composite was confirmed by AFM images. Finally, antibacterial activity of composite was studied against Staphylococcus aureus. Results show that the bactericidal effect of this composite is significant and suggesting the composite to be promising candidate for applications in fields.     

Growth of Ag and Au Nanoparticles on Reduced and Oxidized Rutile TiO2(110) Surfaces

The nucleation and growth of Au and Ag nanoparticles on rutile TiO₂(110)–(1 × 1) surfaces in different oxidation states is studied by means of photoelectron spectroscopy (PES) and scanning tunneling microscopy (STM). Au and Ag nanoparticles were found to bind much more strongly to oxidized TiO₂(110) model supports than to reduced TiO₂(110) surfaces, as directly revealed by STM. Detailed PES studies addressing small Au and Ag particles complete this picture and show that the PES core level spectra acquired on Au/TiO₂(110) and Ag/TiO₂(110) can be best described by fitting with two binding energy (BE) components. Particularly for coverages in the sub-monolayer regime and for depositions at low temperatures (100 K) the PES core level spectra must be fitted with at least two BE components. The higher BE component is attributed to atoms at the interface between the metal clusters and the TiO₂(110) support. For Au/TiO₂(110), the two BE components were evident in the core level spectra for higher coverage than for Ag/TiO₂(110), consistent with different growth modes for Au (initially 2D) and Ag (3D) on TiO₂(110). Finally, strong evidence for charge transfer from Ag nanoparticles to the TiO₂(110) support is presented, whereas the charge transfer between Au nanoparticles and the TiO₂(110) support is very small.     

Ag/TiO2空心微球的制备及光催化杀菌性能的研究

采用一步水热法,以NH4HF2作为形貌控制剂、反应温度为200℃、反应时间为12h,制备锐钛矿型TiO2空心微球,并通过紫外光还原法在TiO2表面沉积单质银.采用SEM、TEM、XRD以及EDS对样品进行表征,以罗丹明B作为模拟污染物表征样品的催化性能.锐钛矿型TiO2空心微球在40 min时降解率达93％,载银二氧化钛复合材料的光催化性能优于纯二氧化钛,当载银量达到2.5％时,光催化活性最佳,在30 min时降解率为98％.采用抑菌圈法表征其杀菌性能,其抑菌圈的直径达16 mm.     

Synthesis of Ag2O Coated TiO2 Nanoparticles by Sonochemically Activated Methods for Enhanced Photocatalytic Activities

Topics in Catalysis - TiO2 nanoparticles were successfully synthesized by sol-hydrothermal (SH) method using sonochemically activated precursors. Sonochemical activation yields product bearing...     

The influence of Si-modified TiO2 on the activity of Ag/TiO2 in CO oxidation

Nanocrystalline TiO₂ and Si-modified TiO₂ with Si/Ti ratios 0.01, 0.05, 0.1, and 0.3 were prepared by the solvothermal method and employed as the supports for Ag/TiO₂ catalysts for CO oxidation reaction. The incorporation of Si into the TiO₂ lattice in the form of Ti–O–Si as revealed by FT-IR results could inhibit the agglomeration of TiO₂ crystallites, resulting in an increase of both surface area and metal dispersion. However, there existed an optimum content of Si/Ti at ca. 0.05–0.1 which resulted in an improved catalytic activity of Ag/TiO₂ in CO oxidation. Based on the O₂-temperature program desorption (O₂-TPD) results, the catalysts with appropriate amounts of Si/Ti exhibited higher amount of O₂ adsorption and much lower desorption temperature. It is suggested that the presence of Ti–O–Si promoted the formation of active oxygen species and increased the mobility of lattice oxygen so that the catalytic activity was enhanced. There was no improvement in CO oxidation activity of the Ag/TiO₂ catalyst when the Si/Ti was further increased to 0.3 due probably to the formation of amorphous SiO₂ instead of the Ti–O–Si bond.     

Investigation of TiO2 Nanoparticles: Thermal Kinetics and Gamma Radiation Effects

Silicon - This paper is part of a research project to develop natural dye-sensitized solar cells. The behavior of surface water, especially the adsorption and dissociation characteristics, is a key...     

TiO_2对Ag/Al_2O_3吸附剂的柴油吸附脱硫性能的影响

采用浸渍法制备不同Ti O2含量的Ag/Ti O2-Al2O3吸附剂,以含硫量为245.36 mg·L-1的商品柴油作为考察对象,常温、常压条件下采用静态评价进行吸附脱硫性能研究。结果表明,经过Ti O2改性的Ag/Al2O3吸附剂柴油吸附脱硫活性有较大幅度提高。通过X射线衍射、N2物理吸附、O2化学吸附和NH3程序升温脱附等研究Ti O2改性剂的影响。关联活性测试和表征结果发现,吸附剂的吸附脱硫活性受吸附剂比表面积、活性金属Ag分散度和吸附剂表面酸协同影响。吸附剂比表面积越大,活性金属Ag分散度越高,吸附剂表面弱酸性位点数量越多,强酸性位点数量越少,吸附剂吸附脱硫活性越高。2%Ag/4%Ti O2-Al2O3的吸附脱硫活性最高,饱和硫容达2.11 mg·g-1。     

纳米二氧化钛的微乳液制法

介绍了影响微乳液法制备纳米二氧化钛微粒的因素、国内外的研究动态和进展以及最新的研究热点。     

纳米Al_2O_3和TiO_2对PVDF膜结构与性能的影响

分别将纳米二氧化钛(Ti O2)、纳米氧化铝(Al2O3)颗粒与PVDF复合,采用相转化法制备出PVDF/Ti O2和PVDF/Al2O3复合膜。考察了纳米粒子比例对膜纯水通量、截留率、力学性能的影响。采用傅立叶变换红外光谱仪和X射线衍射仪探究了纳米粒子对PVDF膜结构的影响;采用扫描电子显微镜分析了膜表面、断面和内部的形貌以及成孔情况。结果表明,通过两种纳米材料改性后,膜的孔结构均得到了改善;PVDF/Ti O2复合膜的亲水性优于PVDF/Al2O3复合膜,但力学性能不及后者。     

Bi、S共掺杂对TiO_2纳米颗粒的结构和光催化性能的影响

以钛酸丁酯、硝酸铋和硫脲为原料,采用溶胶-凝胶法制备了不同n[Bi(S)]/n(Ti)的Bi、S共掺杂的TiO2光催化剂。采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、激光拉曼光谱(FT-Raman)、紫外-可见漫反射吸收光谱(UV/vis DRS)、微反等方法对光催化材料进行了研究。结果显示,Bi、S元素在TiO2纳米颗粒中分别以Bi2O3和SO42-形式存在,共掺杂未能改变TiO2的锐钛矿结构。Bi掺杂后,通过形成Bi—O—Ti键在TiO2禁带中产生了杂质能级,降低了纳米材料的禁带宽度,从而提高了光吸收效率;而S的引入,增多了催化剂表面的酸性位,有利于光催化活性的提高。Bi、S掺杂能明显改善TiO2纳米颗粒光催化甘油水溶液制氢的性能,3%Bi、S共掺杂TiO2具有最高的产氢速率,在紫外光和模拟太阳光照射下,其产氢速率可分别达到1 514.9和190.2μmol/(h·g)。     

纳米TiO2颗粒在制冷工质中的分散

纳米TiO2颗粒在制备和应用过程中极易团聚,解决其分散问题是纳米TiO2颗粒在制冷系统中应用的基础和前提. 本工作利用目测沉降观察、分光光度计吸收测量法和激光粒度分析法,实验研究了纳米TiO2颗粒在制冷工质中的分散特性. 结果表明,纳米TiO2颗粒在制冷剂中分散较稳定,制冷剂介电常数和极性是主要的影响因素;Span-80可以作为纳米TiO2颗粒在制冷剂中的分散剂;温度对纳米TiO2颗粒在制冷剂中的分散稳定性影响明显. 研究结果可为纳米TiO2颗粒在制冷系统中的应用研究提供基础数据.     

SnO2/TiO2纳米粒子光催化降解对硝基苯酚

采用硬脂酸法制备出SnO2/T iO2复合光催化剂,用X光衍射仪对粉体进行了必要的表征。样品经500℃焙烧2h后,5%(摩尔分数)Sn4 -T iO2纳米粉末的平均粒径约为14nm。通过粉体对对硝基苯酚的降解情况对其光催化活性进行了测试,结果表明与纯T iO2相比,SnO2/T iO2的光催化活性有较大提高,当SnO2的掺入量为摩尔比5.0%时催化活性最高。以高压汞灯为光源,对硝基苯酚的初始浓度为100m g.L-1、催化剂5%(摩尔分数)Sn4 -T iO2投加量为1.0g.L-1时,对硝基苯酚的光催化降解效果最好。     

悬浮态纳米TiO2光催化降解喹啉的研究

采用Degussa P25 TiO2为光催化剂,在紫外光的照射下考察了有无空气、P25 TiO2催化剂用量、喹啉初始浓度、pH值及氯离子对光催化降解过程的影响。实验结果表明:空气促进喹啉和总有机碳的降解率,喹啉初始浓度越低,光催化降解过程越充分,P25 TiO2催化剂适宜浓度为0.70g/L,碱性环境下有利于喹啉的降解,pH=8.38时总有机碳的降解率达到94.47%,随着氯离子掺杂浓度的提高,总有机碳的降解率逐步下降。     

Preparation and Characterization of Pt/C and Pt/TiO2 Electrocatalysts by Liquid Phase Photodeposition

The preparation of carbon and titanium dioxide supported Pt catalysts through a photochemical and photocatalytic routes were investigated. The catalysts were prepared by irradiation with UV-light (365 nm) at room temperature using H₂PtCl₆ and C₁₀H₁₄O₄Pt (Pt(acac)₂) as platinum precursors. The kinetic studies revealed that H₂PtCl₆ produced metallic platinum faster than Pt(acac)₂ and also showed that the amount of platinum deposited on TiO₂ was higher than on carbon. The samples were characterized by X-ray diffraction, SEM/EDS and cyclic voltammetry. X-ray diffraction permitted to identify the crystallographic (111) and (200) planes from platinum metal on the catalysts synthesized, the intensity of peaks depends of the amount of platinum deposited. SEM/EDS test confirmed what it was found by the kinetics studies. The electrocatalytic activity was compared with a commercial Pt E-Tek catalyst (10 wt%). The electrochemical results showed that Pt/C-AA catalyst synthesized by liquid phase photo-deposition method has stability in acid media and high distribution of the actives sites on the electrode surfaces. It could be considered as a candidate for electro-catalyst for polymer electrolyte fuel cell. The Pt/TiO₂ catalysts did not present electrochemical activity.     

Ag/TiO2光催化降解茜素红

以钛酸四丁酯为前驱体,冰醋酸为水解抑制剂,用溶胶-凝胶法制备了纳米Ag/TiO₂复合催化剂,测定了催化剂对茜素红溶液的光降解活性。结果表明,Ag/TiO₂催化剂具有较高的光催化活性。     

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.     

光催化还原法制备载Ag光催化剂

采用光催化还原法在大颗粒负载型TiO2表面上制备了负载型Ag/TiO2光催化剂。以对甲基橙溶液的降解活性为研究对象，考察了光催化剂制备过程中AgNO3溶液浓度，还原反应气氛，还原反应时间，反应液pH值，EDTA的加入等反应条件的影响。研究了光催化还原法制备载Ag催化剂的可行性，得出光催化还原法的优化制备条件。     

溶剂及TiO2纳米粒子对血红蛋白电子传递的影响

系统考察了血红蛋白分子(Hb)在石墨电极上的直接电子传递性质,结果表明有机溶剂二甲亚砜(DMSO)、表面活性物质双十二烷基二甲基溴化铵(DDAB)及纳米粒子(TiO2)均可改善血红蛋白与电极之间的直接电子传递。在0.1 mol.L-1pH=7.0的PBS缓冲溶液中,固定化Hb显示了一对稳定的峰形对称的氧化还原峰,在扫速为100 mV/s时其电子传递速率常数为3.4 s-1,在20到500 mV/s的扫速范围内,电极响应是一个表面控制过程,其式量电位为Hb/TiO2/DMSO/PG的-(296±8)mV和Hb/TiO2/DDAB/PG的-(172±6)mV(vs.Ag/AgCl)。