水热制备TiO2纳米管及其光催化性能

本文利用TiO₂粉体在高浓度NaOH溶液中水热反应制备TiO₂纳米管,采用X射线衍射(XRD)、扫描电镜(SEM),透射电镜(TEM),紫外可见分光光度计(UV-Vis)考察了NaOH浓度、水热反应温度、水热反应时间等因素对TiO₂纳米管结构和性能的影响。结果表明：当NaOH浓度为10mol/L,水热反应温度为160℃,水热反应时间20h时,所制备的TiO₂纳米管显示出较高的光催化活性,经紫外光照30min后,对甲基橙(MO)的降解率可达75.48%。     

Pd/TiO2/棉花纤维复合催化材料的制备与性能研究

先通过浸渍-提拉法将纳米TiO_2对棉花纤维表面进行修饰,再通过浸渍-NaBH4还原法将Pd纳米颗粒沉积在TiO_2/棉花纤维(TC)表面,制备得到Pd/TiO_2/棉花纤维复合催化材料(PTC)。所制备的复合催化材料用于室温氧化分解甲醛,研究了Pd负载量对催化性能的影响。结果表明,PTC催化材料具有远低于粉末状样品的气阻,此特点对催化材料的实际应用具有非常大的优势;该催化材料能有效室温分解甲醛成CO_2和H_2O。PTC催化材料的催化活性随Pd含量(0.25%～1.0%,质量分数)的增加而增加。鉴于PTC催化材料具有低气阻、轻质、使用灵活的属性和良好催化效率以及载体棉花原料来源广泛、成本低等优点,具有良好的实际应用于室内空气净化和相关催化过程的潜力。     

纳米柱状多孔WO3- x /TiO2 薄膜的电致变色性能

采用反应磁控溅射在掠射角度α=0°和α=80°的条件下制备氧化钨（WO_3-x）薄膜,然后在其表面沉积二氧化钛（TiO₂）。利用X射线衍射仪（XRD）、场发射扫描电镜（FE-SEM）和X射线光电子能谱仪（XPS）对WO_3-x/TiO₂薄膜的晶体结构、表面/断面形貌以及表面化学成分进行表征。在三电极体系1 mol/L LiClO₄/PC溶液中,采用电化学工作站和紫外-可见分光光度计测试了WO_3-x/TiO₂薄膜的电致变色性能。XRD结果表明,WO_3-x/TiO₂薄膜为非晶态结构,与掠射角度无关。当掠射角度为80°时,获得了纳米柱状多孔薄膜。从 W 4f和Ti 2p的XPS谱图确认氧化钨为亚化学计量比的WO_3-x,而氧化钛为满足化学计量比的TiO₂。与致密薄膜相比,纳米柱状多孔薄膜需要较低的驱动电压且具有较快的响应速度。纳米柱状多孔薄膜的电荷容量为83.78 mC,是致密薄膜电荷容量30.83 mC的2倍以上。在±1.2 V驱动电压下,注入和脱出离子扩散速率分别为D_in=5.69×10^-10 cm²/s和D_de= 5.08×10^-10 cm²/s。与纯WO₃薄膜相比,WO_3-x/TiO₂薄膜的电致变色循环稳定性更好。纳米柱状多孔薄膜在可见光范围内具有较大的光调制幅度,因此其光密度变化（ΔOD）大于致密薄膜。     

MSM结构TiO2基紫外探测器的制备及光电特性研究

采用RF磁控溅射技术在石英衬底上生长了厚度可调的锐钛矿相TiO₂薄膜,继而采用光刻技术在薄膜上生长了Ag叉指电极,获得了MSM结构TiO₂基紫外探测器。I-V特性测试结果表明Ag与TiO₂之间表现出优良的欧姆接触特性,所制备探测器为欧姆接触。此外,TiO₂薄膜厚度对探测器的光电性能影响显著,当薄膜厚度达到197 nm时,光电性能达到最高。此时,光电流高出暗电流近2.5个数量级,紫外光区的响应度高出可见光区近2个数量级。所制备Ag/TiO₂MSM紫外探测器表现出高灵敏度和可见盲特性。     

Fe2O3-CaO-TiO2 体系下铁酸钙的合成过程及TiO2 和CaTiO3 的影响

为了确定高钛型钒钛磁铁矿烧结过程中铁酸钙的生成是受TiO₂还是TiO₂和CaO形成的CaTiO₃影响,首先利用Fe₂O₃和CaO的纯试剂合成了铁酸钙,并研究了TiO₂和CaTiO₃对钛铁酸钙 （FCT） 形成的影响。在Factsage 7.0软件进行热力学计算的基础上,通过在空气气氛下进行烧结,获得了在1023~1423 K温度范围内、不同烧结时间的不同样品。通过X射线衍射和扫描电镜-能谱分析等表征手段,对烧结样品的物相转变和微观结构变化进行了表征。发现FCT的形成过程主要分为2个阶段：前一阶段为1023~1223 K温度范围内Fe₂O₃与CaO之间的反应,合成产物为Ca₂Fe₂O₅,反应方程式为“Fe₂O₃(s)+ 2CaO(s)= Ca₂Fe₂O₅(s)”;后一阶段为1223~1423 K温度范围内Ca₂Fe₂O₅和Fe₂O₃的反应,主要产物为CaFe₂O₄,反应为“Ca₂Fe₂O₅(s)+ Fe₂O₃(s)= 2CaFe₂O₄(s)”,该阶段尤其是温度为1423 K时,反应速率显著加快,随温度的升高CaTiO₃显著增加。然而,Ti元素在铁酸钙中的固溶很难实现,TiO₂与铁酸钙之间的反应不是形成FCT的有效途径。随着保温时间的延长,CaTiO₃和FCT相界中Fe元素含量增加。FCT主要是通过Fe组分在CaTiO₃中固溶形成的,主要反应是“Fe₂O₃+CaTiO₃(s)=FCT(s)”。     

新型TiO2 NTs制备和结构控制及其硝基苯光催化性能研究

实验采用二次阳极氧化法制备高度有序的阵列式TiO2纳米管（TiO2 NTs）,分别利用扫描电镜（SEM）、能谱仪（EDS）、X射线衍射仪（XRD）和紫外-可见漫反射光谱仪（UV-vis DRS）对制得的TiO2 NTs的微观形貌及光响应范围进行表征与测试。SEM显示经过二次阳极氧化处理后,TiO2 NTs的形貌发生较大改变,呈现出良好的阵列效果。UV-vis DRS光谱显示光响应范围明显发生红移。将硝基苯作为目标有机污染物,利用TiO2 NTs作为光催化剂对其进行光催化降解。结果显示,TiO2 NTs能有效降解废水中的硝基苯,并且经二次阳极氧化制得的阵列式TiO2纳米管（2-step TiO2 NTs）的光催化活性远远优于经一次氧化的TiO2纳米管（1-step TiO2 NTs）,能显著提高对硝基苯的降解效率。推测活性增加的原因是经二次氧化形成的阵列式双层纳米管结构增大了催化剂的比表面积,同时增加光通道,使TiO2纳米管吸光范围显著增大,提升硝基苯的降解速率。     

BN/Al2O3 复合粉末及其聚合物基复合材料的制备与导热性能

采用固-液相共混法制备了多种BN/Al₂O₃复合粉末,通过冻融法和表面修饰法对BN进行了改性处理,改变表面修饰剂类型和摩尔比得到了前驱体和烧结态BN/Al₂O₃复合粉末,并利用机械混合法制备了聚合物基BN/Al₂O₃复合材料,并测试分析了其导热性能。结果表明,经冻融处理的BN分散性和界面相容性明显优于未经冻融处理的BN。多巴胺对BN的改性效果优于聚乙二醇。采用多巴胺作为表面修饰剂且BN与Al(NO₃)₃的摩尔比为1:1时,能够得到纳米Al₂O₃均匀包覆的微米BN粉末,即BN/Al₂O₃微纳复合粉末,其聚合物基复合材料的导热系数可达0.62 W·m^-1·K^-1,是纯聚合物导热系数的3倍,是采用纯微米BN粉末制备的聚合物基复合材料导热系数的1.5倍。在BN表面附着的Al₂O₃可以形成层状热传导通道,能够有效提高聚合物基BN/Al₂O₃复合材料的热导率。     

非平衡磁控溅射La-Ti/WS2 自润滑薄膜的摩擦磨损行为

要满足航天器机械转动部件在恶劣工况下的工作,需研制高硬度、低摩擦系数的固体润滑薄膜。采用非平衡磁控溅射法分别制备了纯WS₂薄膜、Ti掺杂WS₂复合薄膜和La-Ti掺杂WS₂复合薄膜。分析了薄膜的微观形貌、成分、硬度和摩擦学性能。结果表明,与纯WS₂薄膜和Ti/WS₂复合薄膜相比,La-Ti/WS₂复合薄膜的微观结构更加致密。La-Ti/WS₂复合薄膜的硬度H和弹性模量E也显著提高。此外,La-Ti/WS₂复合薄膜的摩擦系数减小,并且H/E比值增大,La-Ti/WS₂复合薄膜的磨损率降低。结果表明,La的掺杂有助于在摩擦接触表面形成稳定的转移膜,提高La-Ti/WS₂复合薄膜的耐磨性和承载能力。     

铜掺杂TiO2纳米管阵列薄膜的制备及表征

本文提出了一种磁控溅射和阳极氧化相结合制备Cu掺杂TiO₂纳米管(Cu-TNT)阵列的方法。掺杂后的样品通过扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)和X射线光电子能谱(XPS)等手段对其结构和光电性能做了研究与分析。研究结果表明：Cu以离子形态均匀地掺杂进入TiO₂纳米管中,且为取代掺杂;Cu掺杂对TiO₂纳米管(TNT)的生长具有抑制作用,对TNT的形貌有明显影响;Cu掺杂对TNT晶体生长取向也有明显影响,抑制锐钛矿(101)晶面的生长,使(101)晶面产生晶格畸变、晶面间距变宽并促进锐钛矿(004)晶面的择优生长。瞬态光电流响应分析表明Cu掺杂TNT有利于抑制光生电子-空穴对的复合速率,提高太阳能利用率。     

无模板剂的溶胶-水热法合成具有可见光响应的氮掺杂混晶 TiO2(锐钛矿/金红石/板钛矿)纳米棒束

采用无模板剂的溶胶-水热法制备了具有可见光响应的N掺杂锐钛矿/金红石/板钛矿型TiO_2(N-TiO_2)纳米棒束,并利用X射线衍射(XRD)、透射电镜(TEM)、紫外-可见光漫反射光谱(UV-Vis DRS)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)等手段对获得的样品进行了表征。以甲基橙为模型反应物,评价了N-TiO_2纳米棒束的光催化活性。表征结果结合光催化活性评价结果显示,与P25-TiO_2相比,N掺杂、混晶及纳米棒束之间的协同作用是所制备的混晶N-TiO_2纳米棒束具有良好光催化活性的主要原因,并对混晶N-TiO_2纳米棒束光催化降解甲基橙的机理进行了探讨。     

纳米颗粒增强TiO_2涂层的制备及其防污性能

为提高二氧化钛涂层的防污性能,采用KH-550硅烷改性锐钛矿型TiO_2颗粒,并充分分散于二氧化钛凝胶涂层中。通过降解亚甲基蓝溶液、细菌贴附试验、藻类贴附试验,分别评价了涂层的光催化性能、抗菌性能及抗藻类附着性能,并利用激光共聚焦显微镜及扫描电子显微镜对藻类在涂层表面的附着情况进行分析。结果表明,添加TiO_2纳米颗粒涂层的防污性能较未添加TiO_2纳米颗粒涂层有较大程度的提高。添加粒径为5~10 nm TiO_2颗粒的二氧化钛涂层对小球藻、三角褐指藻及小新月菱形藻的附着降低率分别达到了92.1%、71.5%和62.1%,相较于纯二氧化钛涂层对3种藻类的附着降低率分别提高了29.7%、68.4%和43.5%。TiO_2颗粒的加入可以有效地提高涂层的光催化性能,光催化使得涂层具有亲水、抗菌及自清洁的性能进而有利于提高涂层的防污性能。     

镁合金表面TiO2薄膜制备技术研究进展

综述了目前镁合金表面TiO2薄膜制备技术的研究情况,重点介绍了溶胶-凝胶法、化学镀、液相沉积法、物理气相沉积法、电沉积法、喷雾热解沉积法、原子层沉积技术、激光熔覆、热喷涂等工艺的原理和制备技术.     

Structure differences between TiO2 and phosphorus implanted TiO2 films caused by thermal treatment

The titanium oxide film has been deposited on Si wafers (110) by unbalance reactive magnetron sputtering and modified by phosphorus ion implantation and succeeding vacuum annealing. The structural, states of surface chemistry and surface morphology of the films have been investigated by X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS), atomic force microscope (AFM) and Scanning Electron Microscope (SEM), respectively. The results of XRD show rutile structure of as-deposited film, which is not changed by phosphorus implantation and vacuum annealing. However, a slightly shift of the peaks position to higher degree and the half width increases after ion implanted and vacuum annealing represent that the variety of the structure film caused by these treatments. The surface roughness is inclined to increase with the rising of annealing temperature for both undoped and P doped titanium oxide films. The surface chemistry presents significant difference between undoped and phosphorus doped films after a vacuum annealing, it may be attributed to the different evolvement of the surface defects existing in the film, which may be considered as an important influencing factor in the blood compatibility of the titanium oxide film.     

TiO2/膨润土复合光催化材料的常温制备及性能研究

采用改进的溶胶-凝胶法,在以水为主要溶剂的反应体系中,控制钛酸四丁酯充分水解、缓慢聚合,在 常压、低温(70℃)的温和条件下制备出稳定的TiO₂纳米晶溶胶,并利用TiO₂纳米晶溶胶在膨润土表面负载,获得TiO₂/膨润土复合光催化材料。采用 X 射线衍射、扫描电镜、比表面积测定等研究手段对样品的结构形貌进行了表征,并考察了其光催化活性。结果表明：较高的水用量有利于TiO₂晶体形成,当去离子水:钛酸四丁酯摩尔比大于167:1时,在溶胶体系中出现了锐钛矿型TiO₂纳米晶体;TiO₂纳米晶主要负载于膨润土表面,并未嵌入到膨润土层间结构,但相对于单一膨润土,TiO₂负载显著提高了材料比表面积;当去离子水:钛酸四丁酯摩尔比=192:1时,在紫外光照射下,复合光催化材料表现出最高的光催化活性,对亚甲基蓝的降解率达到93.8%。     

Preparation and characterization of nano TiO2/micron Cr2O3 composite particles

Nano-TiO₂/micro-size Cr₂O₃ composite particles were first prepared by hydrolysis of Ti(OBu)₄ in an abundant acidic aqueous solution without calcinations at room temperature. XPS analysis shows that the element C, O, Ti and Sn existed on the surfaces of the composite particles. Observation by field emission scanning electronic microscope shows TiO₂ particles of 10-15 nm covers on Cr₂O₃ powder surfaces to form nanometer/micron composite particles. UV-vis spectra show a red shift of the absorption edge and a significant increase of absorption intensity in the visible region. These results confirm that TiO₂ of anatase type can be synthesized on the surface of Cr₂O₃.     

Primary investigation of corrosion resistance of Ni-P/TiO2 composite film on sintered NdFeB permanent magnet

In this paper, an electroless nickel plating and sol-gel combined technique used to prepare the Ni-P/TiO₂ composite film on sintered NdFeB permanent magnet is described and the composite film was characterized by X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM), and energy dispersive X-ray spectrometer (EDX). The corrosion resistance of Ni-P/TiO₂ film was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The self-corrosion current density (i_corr) of Ni-P/TiO₂ composite film is 2.38μA/cm² in 0.5mol/L H₂SO₄ solution about 33% of that of Ni-P coating and 0.22μA/cm² in 0.5mol/L NaCl solution about 14% of that of Ni-P coating, respectively. In 0.5mol/L H₂SO₄ and 0.5mol/L NaCl solutions, the polarization resistance (Rp) of the composite film is 12.5kΩ cm² and 120kΩ cm², about 1.6 and 2 times that of Ni-P coating, respectively. The results indicate that Ni-P/TiO₂ composite film has a better corrosion resistance than Ni-P coating.     

High transmittance and superhydrophilicity of porous TiO2/SiO2 bi-layer films without UV irradiation

In order to obtain the TiO₂ films with high transmittance and superhydrophilicity without UV irradiation, porous TiO₂/SiO₂ bi-layer films were prepared by spin coated SiO₂ sol and TiO₂ sol including polyethylene glycol 2000 (PEG 2000) onto glass and subsequent calcination at 550 °C. Meanwhile, factors that affect the TiO₂/SiO₂ bi-layer films transmittance and superhydrophilicity were investigated in details by observing their surface morphologies and measuring their water contact angles (WCAs), spreading time and transmittances. The results indicated that the as-prepared TiO₂/SiO₂ bi-layer film showed superhydrophilicity without UV irradiation when 0.5 wt.% PEG 2000 was added in TiO₂ sol. At the same time, its maximum transmittance was as high as 92.3%. The spreading time was only about 0.16 s. More importantly, the resultant film had an excellent stability of the superhydrophilic property.     

Modification of TiO2 nanorods by Bi2MoO6 nanoparticles for high performance visible-light photocatalysis

In this work, TiO₂ nanorods were prepared by a hydrothermal process and then Bi₂MoO₆ nanoparticles were deposited onto the TiO₂ nanorods by a solvothermal process. The nanostructured Bi₂MoO₆/TiO₂ composites were extensively characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the Bi₂MoO₆/TiO₂ composites was evaluated by degradation of methylene blue. The Bi₂MoO₆/TiO₂ composites exhibit higher catalytic activity than pure Bi₂MoO₆ and TiO₂ for degradation of methylene blue under visible light irradiation (λ > 420 nm). Further investigation revealed that the ratio of Bi₂MoO₆ to TiO₂ in the composites greatly influenced their photocatalytic activity. The experimental results indicated that the composite with Bi₂MoO₆:TiO₂ = 1:3 exhibited the highest photocatalytic activity. The enhancement mechanism of the composite catalysts was also discussed.