Photocatalytic oxidation of gaseous benzene over nanosized TiO2 prepared by solvothermal method

Nanosized TiO2 particles were prepared by solvothermal method using tetrabutyl titanate as precursor,ethanol and water as solvents,and a facile immobilization method of nanosized TiO2 particles on woven glass fabric was developed. The samples obtained under various preparation conditions were charac-terized by means of thermo gravimetric analysis(TG) and differential scanning calorimetry(DSC) ,X-ray diffraction(XRD) ,transmission electron microscopy(TEM) ,high resolution-transmission electron mi-croscopy(HR-TEM) ,and Brunauer-Emmett-Teller(BET) . The results show that the cube-shape of TiO2 prepared by solvothermal method has good crystallinity of(101) surface,higher thermal stability and large specific surface area. Scanning electron microscopy(SEM) images confirmed that the immobi-lized TiO2 film was uniformly distributed and clung to the substrate firmly. The photocatalytic activity of the catalysts was tested using photocatalytic oxidation of gaseous benzene. The results show that the TiO2 calcined after solvothermal treatment suffers from lower specific surface area,and hence de-creases its photocatalytic activity. The photocatalytic activities of the TiO2 by solvothermal treatment with or without calcination in degradation 400 mg/m3 benzene are 3.7 and 4.1 times as high as catalyst without solvothermal treatment,respectively.     

Nanocrystalline TiO2 thin film electrodes prepared by common pressure hydrothermal method at low temperature

Dye-sensitized solar cells (DSSCs) based on nanocrys- talline TiO2 thin film electrodes have been widely investi- gated since they were invented by Gr?tzel et al. in 1991[1-3]. Nanocrystalline TiO2 thin film electrodes are usually pre- pared by coating TiO2 colloid with organic additives on conductive glass substrates and annealing at 400-450℃ to remove organic additives and achieve good electrical contact between TiO2 particles and between TiO2 particles and conductive substrates, which…     

La<Subscript>2</Subscript>Zr<Subscript>2</Subscript>O<Subscript>7</Subscript> TBCs toughened by Pt particles prepared by cathode plasma electrolytic deposition

La₂Zr₂O₇ thermal barrier coatings (TBCs) with dispersed Pt particles were prepared by cathode plasma electrolytic deposition (CPED) with ceramic balls added to the cathode region. Compared with the conventional CPED, when ceramic balls are used in the cathode region, the plasma discharge ignition current density decreases approximately 62-fold and the stable plasma discharges occur at the whole cathode surface. Such TBCs with a thickness of 100 μm exhibit a crack-free surface and are composed of pyrochlore-structured La₂Zr₂O₇. Cyclic oxidation, scratching, and thermal insulation capability tests show that such TBCs not only exhibit high resistance to oxidation and spallation but also provide good thermal insulation. These beneficial effects are attributed to the excellent properties of TBCs, such as good thermal insulation because of low thermal conductivity, high-temperature oxidation resistance because of low-oxygen diffusion rate, and good mechanical properties because of the toughening effect of Pt particles.     

SiO2改性对紫外光固化木器涂料性能的影响

采用SiO₂对紫外光(UV)固化木器涂料进行改性,通过优化工艺参数制备了UV固化木器涂层。对涂层的力学性能(硬度、附着力和耐冲击强度)和光泽度进行了测试。结果表明:当SiO₂质量分数为0.66%～1.32%,干燥时间2 min,UV灯3盏时,UV固化木器涂层具有良好的硬度、附着力和冲击强度; 但是当SiO₂质量分数高于1.32%时,涂层的力学性能反而下降。光泽度检测结果表明,UV固化涂层的光泽度随SiO₂含量的升高而下降; 当SiO₂质量分数超过1.32%时,UV固化木器涂层呈现亚光光泽度。     

Preparation of porous nanocrystalline TiO2 electrode by screen-printing technique

Different paste has been used for preparing porous TiO2 thin film by screen-printing technique, the main component of it comes from commercial TiO2 P25 power. The dye-sensitized solar cell based on this TiO2 thin film without further chemical treatments exhibits high overall conversion efficiency of 5.81%―6.70%, even with low TiO2 content and thin film thickness. The experimental repeatability is nice and the properties of the films are uniform.     

Preparation and optical properties of waterborne acrylic-based cool white coatings

Cool coatings （solar reflective coatings） possess a high total solar reflectance and a high thermal emittance, and they have potential applications in building surfaces, pavements, and oil tanks. By decreasing the accumulation of heat, these coatings can reduce the urban heat island effect to increase thermal comfort and to decrease energy consumption in hot zones. In this work, a cool white coating based on waterborne acrylic was prepared. The reflectance and thermal emittance were measured using an ultraviolet- visible-near-infrared spectrophotometer and the steady- state calorimetric technique, respectively. The cool coating possessed a total solar reflectance of 0.887 and a thermal emittance of 0.85. The linear fitting results indicated that the thickness of the dry film is an important factor that affects the reflectance and that the physical limit of total solar reflectance in practical cool coatings is 0.91. A homemade device developed according to military specification MIL-E-46096C was used to measure insulation temperature differences, and an insulation temperature difference of 29 ℃ was obtained. The above results demonstrated that the cool coating can be applied to buildings.     

聚酰亚胺/无机物纳米杂化材料的研究I.聚酰亚胺(HQDPA/DMMDA)-TiO2纳米杂化物的合成与表征

将钛酸丁酯经乙酸修饰改性和稳定化后在杂化过程中用作ＴｉＯ２前体,采用溶胶－凝胶法由可溶性业胺（ＨＱＤＰＡ／ＤＭＭＤ七经修饰改性的钛酸丁酯溶液混合成与表征进而制得聚酰亚胺－ＴｉＯ２杂化材料,ＸＰＳ分析表明钛酸丁酯已转化成ＴｉＯ２,ＴＥＭ则显示ＴｉＯ２以球状微粒均匀分散在聚酰亚胺基体中,粒径为３０～６０ｎｍ,含１０％ＴｉＯ２的杂化膜是具有高热稳定性与韧性的薄膜,其介电常数为３．５。     

纳米TiO2/硅藻土复合材料光催化降解模拟染料废水研究

用酸性红3R染料溶液模拟染料废水,在可见光强度为91 700μW/cm2,紫外线强度为499μW/cm2的太阳光照射下,研究了自制纳米TiO2/硅藻土复合材料的光催化性能。同时探讨了体系pH、光照时间以及染料初始浓度对光催化效果的影响。实验结果为:当体系溶液pH=3时,光照时间越长,染料初始浓度越低,光催化效果越好。     

TiO2 nanotube arrays and TiO2-nanotube-array based dye-sensitized solar cell

To substitute the non-regular nano-crystalline semiconductor for a novel kind of ordered microstructure is a very important aspect in the domain of dye-sensitized solar cell. One of the researching hot- spots is the highly-ordered TiO2 nanotube architecture. As a new type of titania nano-material, titania nanotube arrays have drawn extraordinary attention due to its distinctive morphology, notable photo-electrical and hydro-sensitive performance. At 100% sun the new kind of TiO2 nanotube arrays solar cell exhibits an overall conversion efficiency of 5.44%. This paper introduces the preparation methods of titania nanotube arrays, the existing problems and recent progress in titania nanotube arrays solar cell.     

Porous α-Al2O3 thermal barrier coatings with dispersed Pt particles prepared by cathode plasma electrolytic deposition

Porous α-Al₂O₃ thermal barrier coatings (TBCs) containing dispersed Pt particles were prepared by cathode plasma electrolytic deposition (CPED). The influence of the Pt particles on the microstructure of the coatings and the CPED process were studied. The prepared coatings were mainly composed of α-Al₂O₃. The average thickness of the coatings was approximately 100 μm. Such single-layer TBCs exhibited not only excellent high-temperature cyclic oxidation and spallation resistance, but also good thermal insulation properties. Porous α-Al₂O₃ TBCs inhibit further oxidation of alloy substrates because of their extremely low oxygen diffusion rate, provide good thermal insulation because of their porous structure, and exhibit excellent mechanical properties because of the toughening effect of the Pt particles and because of stress relaxation induced by deformation of the porous structure.     

Mechanical and thermal properties of AA7075/TiO2/Fly ash hybrid composites obtained by hot forging

In the present paper, multiple reinforcements TiO2 and fly ash were utilized for the fabrication of AA7075 matrix based hybrid composites using stir casting technique followed by hot forging. In hybrid composites, the fly ash content was fixed to 3 wt% while that of TiO2 was varied from 2.5 to 10 wt%. Scanning electron microscopy images revealed homogenous dispersion of both the reinforcements in AA7075 matrix.Compression test was conducted to study the mechanical behaviour of hybrid composites. The hybrid composites showed increase in compressive strength with the incorporation of multiple reinforcements and further increased with the increase in the weight fractions of TiO2 particles. The coefficient of thermal expansion was measured between 50 and 250 ℃ with a high precision thermal mechanical analyser. The thermal coefficient of hybrid composites decreased with the addition of TiO2 and fly ash. However a slight decrease in thermal conductivity of hybrid composites was observed when compared to that of AA7075 alloy.     

丙烯酸酯阳极电泳涂料树脂的制备与性能研究

通过自由基溶液共聚合制备了丙烯酸酯阳极电泳涂料树脂. 研究了不同酸值和羟值的丙烯酸酯单体以及助溶剂对丙烯酸酯电泳漆性能的影响,以及丙烯酸酯树脂的热固化过程和表征了树脂和漆膜的结构. 结果表明,随甲基丙烯酸用量增加,丙烯酸酯树脂水分散体的粒径减小、粘度略有增加、稳定性增强. 以合成条件为丙烯酸酯共聚树脂酸值为64.6 mg KOH/g、羟值为85.5 mg KOH/g、Tg为20℃,一缩二乙二醇单甲醚和异丙醇的体积比为2:3,所得到的电泳涂料具有良好的槽液稳定性,电泳涂膜经热固化后的外观平整、丰满、光亮,硬度为5H,附着力为1级,冲击强度为50kg?cm,耐丁酮摩擦﹥100次.     

Incorporation of nano/micron-SiC particles in Ni-based composite coatings towards enhanced mechanical and anti-corrosion properties

Ni-based composite coatings incorporated with nano/micron SiC particles were fabricated via electrochemical co-deposition in Watts bath,followed by the evaluation of their mechanical and anti-corrosion properties.The micrographic observations suggest that the SiC particles with various sizes can be well incorporated to the Ni substrate.X-ray diffraction(XRD)patterns indicate that SiC particles with smaller sizes could weaken the preferential growth of Ni along(200)facet.In addition,it is found that the incorporated SiC particles with medium micron sizes(8 and 1.5μm)could significantly enhance the micro-hardness of the Ni composite coatings.Nevertheless,electrochemical measurements demonstrate that micron-sized SiC particles would weaken the corrosion resistance of Ni composite coatings ascribed to the structure defects induced.In contrast,the combined incorporation of nanosized(50 nm)SiC particles with medium micron(1.5μm)ones is capable of promoting the compactness of the composite coatings,which is beneficial to the long-term corrosion resistance with negligible micro-hardness loss.     

Photocatalytic degradation kinetics of Rhodamine B catalyzed by nanosized TiO<Subscript>2</Subscript> film

A fixed bed photocatalytic reactor was designed,and dynamic fast scan of UV-Vis adsorption spectrum was adopted to study the photocatalytic degradation dynamic behavior of Rhodamine B,a kind of dye generally recognized as to be degraded difficultly ,on the surface of nanosized TiO2 thin film,The results indicate that the photocatalytic degradation process of Rhodamine B does not comply with the first-order reaction kinetic process ,As a result,a kinetic model of Rhodamine B photocataly tic degradation ,reaction is brough forward ,and the model is proved by the theoretical deduction and experiment.     

Synthesis of TiO2 nanotubes film and its light scattering property

TiO2 nanotubes with diameters of 10 nm and lengths up to 600 nm were fabricated by directly using commercial TiO2 powders P25 as the precursors via sonication-hydrothermal combination approach. TiO2 nanotubes were characterized by means of X-ray powder diffractometer （XRD）, scanning electron microscope （SEM）, selected area electron diffraction pattern （SAED） and transmission elec- tron microscope （TEM）. The light scattering property of film electrodes modified with TiO2 nanotubes was studied and revealed that TiO2 nanotubes can be used as the light scattering centers to increase the light absorption in dye-sensitized solar cells. The TiO2 nanotubes film electrodes mixed with 10% small nanoparticles TiO2 had both strong light scattering property and fine mechanical characteristics, and this kind of electrodes can be used as electrodes in improving the conversion efficiencies of dye-sensitized solar cells.     

纳米氧化钛颗粒表面处理及表征

利用偶联剂钛酸丁酯对纳米二氧化钛颗粒预处理后,进行甲基丙烯酸甲酯（ＭＭＡ）的聚合改性,研究了聚合改性物质的结构和改性后纳米二氧化钛的分散性能。钛酸丁酯与氧化钛表面羟基反应,使氧化钛粒子表面生成交联反应物,甲基丙烯酸甲酸与其反应生成ＰＭＭＡ并均匀包敷于纳米二氧化钛颗粒的表面。通过聚合改性后的纳米二氧化钛颗粒在甲苯中具有良好的分散性能。     

热浸Zn-Ti合金镀层的显微组织与耐蚀性能

为了抑制热镀锌过程中因含硅活性钢引起的镀层超厚生长,本文采用在纯锌浴中加Ti的方法,研究了0.09%Si钢在含低于0.1%Ti的几种锌浴中热浸镀获得的组织,并采用盐雾腐蚀,电化学极化以及X射线光电子能谱等方法,研究了Zn和Zn-Ti镀层的耐蚀性能。结果表明,随着锌浴中Ti含量的增加,Ti对ζ相生长的抑制作用增强,合金层厚度逐渐减薄,Ti能有效地抑制含硅活性钢镀层的超厚生长。当Ti含量大于0.05%时,镀层中出现Γ2粒子。Zn-Ti合金镀层在5%NaCl溶液中发生自发腐蚀的倾向小于Zn镀层,其极化电阻增大,腐蚀电流密度减小,耐蚀性能提高。Zn-Ti镀层表面形成的氧化膜由ZnO 和TiO2组成。锌钛合金镀层的耐腐蚀性能优于纯锌镀层是由于在镀层表面形成了更加稳定的TiO2膜。     

热氧化法制备 TiO2薄膜电极及其光电流性能

采用热氧化钛片的方法制备了TiO2薄膜电极,然后利用X射线衍射（XRD）、扫描电子显微镜（SEM）、荧光光致发光（PL）、拉曼光谱（Raman）、光电流和光电压等实验技术进行表征,考察了不同热处理温度对薄膜的形貌、晶相结构、光学性质和光电流性能等的影响．结果表明：随着热处理温度由3000C提高到600℃,在钛片表面上逐步生成晶粒细小、多孔且荧光强度逐渐降低的纯金红石TiO2薄膜,并可获得分别为0．154mA／cm2和0．3V的最大阳极光电流和光电压,而继续增大热处理温度虽有助于氧化膜的形成,但光电流和光电压则急剧减小．因该热处理方法具有操作简单、生成的表面膜与基底的附着性好且光电性能稳定等特点,使其在TiO2膜电极制备方面有较好的应用前景．     

纳米复合TiO2薄膜光催化降解模拟染料废水研究

以TiCl4,有机羧酸等为主要原料,首先采用常温络合-控制水解技术制备出锶掺杂纳米TiO2无色透明水溶胶,然后使用0.5 mm口径的喷枪,在0.8 MPa压力下,利用普通喷涂技术将所制备的透明溶胶均匀的喷涂在玻璃表面或者烧杯内壁,得到了均匀透明的纳米薄膜。以酸性红3R染料溶液模拟染料废水,研究了锶掺杂纳米TiO2薄膜的光催化性能,同时探讨了体系pH,光照时间以及染料初始浓度对光催化效果的影响。     

纳米二氧化钛-硅藻土复合材料的制备及性能

用酸性红3R染料溶液模拟染料废水,在可见光强度为86200 uw/cm2,紫外线强度为465 uw/cm2的太阳光照射下,研究了纳米TiO2/硅藻土复合材料制备最佳条件的选择.通过SEM、XRD、EDS和IR对样品进行了表征,同时探讨了体系pH,光照时间以及染料初始浓度对光催化效果的影响.结果显示,当酸性水解时间在75 min、中性回流时间为2小时、二氧化钛与硅藻土比为1:3的复合材料催化效果最佳.当体系溶液pH=3时,光照时间越长,染料初始浓度越低,光催化效果越好