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。     

压力烧结制备二氧化钛包覆的石墨烯增强铝基复合材料

使用压力烧结方法制备了石墨烯纳米片（GNP）增强的7075铝基纳米复合材料,提出了一种通过在GNP的表面涂覆二氧化钛（TiO₂）来优化界面结合的新工艺,并比对了原石墨烯及具有包覆层石墨烯对铝基纳米复合材料的力学性能和微观结构的影响。结果表明,与添加纯GNP相比,添加具有TiO₂涂层的GNP的纳米复合材料的力学性能提高。相比于基体,TiO₂包覆GNP增强的纳米复合材料的屈服强度、抗拉强度和显微硬度分别增加了38.9%、34.4%和20.1%。性能的进一步改善是由于TiO₂涂层优化了增强相与基体之间的界面结合,从而提高了载荷传递的有效性。     

石墨烯量子点/纳米Al2O3协同生长润滑转移膜机制∗

为改善环氧树脂(EP)的摩擦学性能,将氮掺杂的石墨烯量子点(N-GQDs)和 Al2O3 纳米颗粒(Nano-Al₂O₃ )杂化物添加到环氧树脂中制备 EP 纳米复合材料。 利用 MRH-1A 摩擦试验机考察纳米复合材料在 PAO 油润滑条件下的摩擦磨损性能, 结合磨损表面的形貌及摩擦化学分析,研究界面转移膜的形成机理和润滑效应。 试验结果表明,3N-GQDs-1Nano-Al₂O₃ / EP 纳米复合材料获得了最好的摩擦学性能,其最低摩擦因数和磨损率分别为 0. 08 和 7. 4×10^-5 mm³ / Nm。 同时对偶金属表面上能够观察到一层均匀的转移膜,其中 C、N、O 元素主要分布于沟壑,而 N、Al 元素则集中于高台区域。 机理分析表明,N-GQDs 和 Nano-Al₂O₃ 有效促进了转移膜的生成,从而避免了摩擦界面的直接接触。     

SnO2@TiO2核-壳纳米线的制备及其光催化性能研究

本文通过固-液-气(VLS)生长机制,利用化学气相沉积法(CVD)制备SnO₂纳米线。利用原子层沉积(ALD)以钛酸四异丙酯为前驱体在SnO₂纳米线表面沉积不同厚度的TiO₂壳层,形成SnO₂@TiO₂核-壳纳米线结构。通过中间Al₂O₃插层,分别制备出金红石和锐钛矿两种不同晶型的TiO₂,从而制备出两种不同复合结构的SnO₂@TiO₂核-壳纳米线。实验研究该复合结构中TiO₂的厚度与晶型对紫外光下光催化降解甲基橙溶液活性的影响。     

非晶TiO2 纳米管形貌对其作为超级电容器电化学性能的影响

采用改进的两步电化学阳极氧化和电化学氢化法制备了不同管径、长度和壁厚的氢化无定型TiO₂纳米管阵列（H@am-TNAs）。结果表明,电化学氢化对TiO₂纳米管阵列的结构影响不大。经过电化学氢化后,纳米管在100 mV·s^-1时的比电容为4.05 mF·cm^-2,比未氢化的管长和管径相同的TiO₂纳米管的比电容大20倍。纳米管的比电容不仅与管长有关,还受管径的影响。通过指数函数拟合,纳米管的长径比呈线性关系。面积电容/长径比达到0.056,几乎相当于锐钛矿相TiO₂纳米管。阳极化处理后的纳米管具有最小的电荷转移阻力和最佳的离子扩散/输运动力学,具有最高的面积容量。此外,为了研究H@am-TNAs纳米管的电化学性能的润湿性,相同的H@am-TNAs电极在C-V和C-P测试前,在电解液中浸泡不同时间,结果表明,比电容随着浸泡时间的增加而减小。     

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%。     

TiO2纳米粒子对铝锂合金微弧氧化膜结构及性能的影响

为改善微弧氧化膜层的耐蚀性及力学性能,向电解液中添加TiO₂纳米粒子后对2297铝锂合金进行了微弧氧化。利用SEM、XRD、EDS、辉光放电表征技术及电化学测试技术,分析了TiO₂纳米粒子对微弧氧化膜结构、力学性能及耐蚀性的影响。结果表明：添加TiO₂纳米粒子后,微弧氧化膜层变得平坦致密。随着TiO₂纳米粒子添加量的提高,膜层表面放电通道的孔径逐渐减小,数量逐渐增多。TiO₂纳米粒子会抑制熔融Al₂O₃与电解液中$ {\rm{SiO}}_{\rm{3}}^{{\rm{2 ^- }}}$的接触,所以膜层中Si元素的含量随TiO₂纳米粒子添加量的增加而逐渐下降(原子数分数从初始的10.27%下降到了3.10%)。显微硬度测试结果表明,TiO₂纳米粒子的引入增加了膜层的致密度及平整度,所以膜层的硬度得到了提升(添加1 g/L TiO₂纳米粒子后硬度提高了15%)。电化学测试结果显示,当微弧氧化的其它条件相同时,TiO₂纳米粒子的适量添加会提升膜层的耐蚀性,但过量添加时,由于膜层放电通道数量的增多等原因,其耐蚀性下降。     

CC/PANI/TiO2复合材料的制备及其光催化性能研究

先采用原位聚合的方法在碳布上负载聚苯胺,然后利用溶剂热法在制备的碳布/聚苯胺(CC/PANI)复合材料上生长二氧化钛纳米片,得到了可便捷分离的CC/PANI/TiO₂复合光催化材料。通过SEM、XRD、UV、FTIR、XPS等手段对所制备的样品进行了形貌和结构表征,并比较了CC/PANI/TiO₂复合材料和纯TiO₂紫外-可见光条件下催化降解RhB的活性差异,结果表明CC/PANI/TiO₂复合材料具有比TiO₂更优异的光催化活性。光致发光光谱说明CC/PANI/TiO₂复合材料的发光强度比纯TiO₂的弱,有效抑制了光生载流子的复合;瞬态光电流响应和电化学阻抗谱(EIS)证明CC/PANI/TiO₂纳米复合材料更有效促进电子-空穴对分离和提高转移效率;活性物质捕捉实验证实?OH和?O_2^-是复合材料光催化降解RhB过程中的主要活性物质。CC/PANI/TiO₂复合材料循环利用6次后,仍然具有较高的催化活性,显示了其在污水处理领域中的良好应用前景。     

g-C3N4/MoS2纳米片异质复合物的球磨法制备及可见光催化性能研究

采用球磨法制备g-C₃N₄/MoS₂纳米片异质复合物,运用X-射线衍射仪、高分辨透射电镜、紫外可见漫反射光谱和荧光发射光谱对异质复合物的结构和形貌进行了表征。结果表明：MoS₂纳米片可进入g-C₃N₄的层间形成异质复合物。以罗丹明B为模拟污染物,在可见光照射下考察了复合物的光催化特性。结果显示,含有2%的MoS₂纳米片与g-C₃N₄形成的异质复合物在120min内对罗丹明B降解率为98%,其降解动力学常数是体相g-C₃N₄为的4.3倍。g-C₃N₄/MoS₂纳米片异质复合物具有十分优良的光催化特性。其催化活性的提高主要归因于光生电子和空穴的有效分离和传输,并根据光捕获实验提出复合物可能的光催化机理。     

氢化TiO2纳米棒的制备及其对Q235碳钢的光生阴极保护特性

随着海洋开发的逐步推进,海洋工程中的金属防腐蚀问题显得愈加重要。目前,可利用半导体的光电效应实现对金属的光生阴极保护,为改善常用的TiO₂光电极材料的弱光吸收和低转换效率问题,文中利用水热法在FTO导电玻璃表面构建一维有序TiO₂纳米棒阵列,并通过氢化处理提高TiO₂对太阳光的吸收和光电流密度。考察了氢化TiO₂纳米棒阵列在海水环境下对Q235碳钢的光生阴极保护特性,结果表明氢化TiO₂纳米棒的光电流密度达到了2.12 mA/cm²,且稳定性良好;当Q235碳钢耦连于模拟太阳光照下的氢化TiO₂纳米棒电极时,其界面反应电阻变小,电极电位较原先的腐蚀电位降低约349 mV,说明氢化TiO₂纳米棒阵列能够对碳钢产生良好的光生阴极保护效应,且该效应在无光条件下能保持至少7 h。     

In situ synthesis of Co3O4/graphene nanocomposite material for lithium-ion batteries and supercapacitors with high capacity and supercapacitance

Co₃O₄/graphene nanocomposite material was prepared by an in situ solution-based method under reflux conditions. In this reaction progress, Co²⁺ salts were converted to Co₃O₄ nanoparticles which were simultaneously inserted into the graphene layers, upon the reduction of graphite oxide to graphene. The prepared material consists of uniform Co₃O₄ nanoparticles (15-25 nm), which are well dispersed on the surfaces of graphene nanosheets. This has been confirmed through observations by field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The prepared composite material exhibits an initial reversible lithium storage capacity of 722 mAh g⁻¹ in lithium-ion cells and a specific supercapacitance of 478 F g⁻¹ in 2 M KOH electrolyte for supercapacitors, which were higher than that of the previously reported pure graphene nanosheets and Co₃O₄ nanoparticles. Co₃O₄/graphene nanocomposite material demonstrated an excellent electrochemical performance as an anode material for reversible lithium storage in lithium ion cells and as an electrode material in supercapacitors.     

The Effect of Heat Treatment of TiO2 Nanoparticles on Photovoltaic Performance of Fabricated DSSCs

The present work focuses on the synthesis of mixed phase TiO₂ nanoparticles with reduced band gaps without even being doped. The synthesis was carried out by chemical route followed by heat treatments at different temperatures to favor rutile incorporation in anatase network. The significance of different heat treatment temperatures on the phase composition of TiO₂ nanoparticles and its effect on optical band gap and the photovoltaic performance are analyzed. The thermal analysis, phases, morphology, and energy band gap of as-synthesized TiO₂ nanoparticles have been characterized by DTA/TG, x-ray diffraction, field-emission scanning electron microscope, transmission electron microscope, and UV-Vis-NIR, respectively. The results show the presence of rutile (~15 nm) and anatase phases (~17 nm) in “as-synthesized” TiO₂ nanoparticles. TiO₂ nanoparticles are heat treated for 2 h at 200, 400, and 600 °C in air. It is observed that heat treatment results in higher photoactivity in visible region of the solar radiation and the material demonstrated high photovoltaic performance in conjunction with N-719. The optical band gap values are found to be in the range of 2.59-2.88 eV. The dye-sensitized solar cells (DSSCs) fabricated by TiO₂ nanoparticles, heat treated at 600 ºC show the energy conversion efficiency (η) of 6.08% with high photo current density (J _sc) of 11.76 mA/cm². The work highlighted in this paper represents the realization of simple method of achieving low band gap semiconductors without being doped, for DSSCs applications.     

Synthesis of titanate/anatase composites with highly photocatalytic decolorization of dye under visible light irradiation

Titanate/anatase nanocomposites consisting of titanate nanotubes and leaf-like anatase TiO₂ nanoparticles were successfully prepared via a novel combinational hydrothermal method. The samples were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The activity of the nanocomposites was examined by photocatalytic decolorization of rhodamine B under visible light irradiation. It is found that the nanocomposites exhibited a much improved photocatalytic activity in comparison with titanate nanotube, anatase TiO₂ nanoparticle, and even the commercial Degussa P-25. The photocatalytic mechanism of the as-prepared nanocomposites was discussed.     

Effect of Nd2O3 addition on the surface phase of TiO2 and photocatalytic activity studied by UV Raman spectroscopy

TiO₂ modified with Nd₂O₃ (Nd-TiO₂) nanoparticles were prepared by a co-precipitation method and utilized as the photocatalysts for the degradation of Rhodamine B (RhB). The influence of Nd₂O₃ on the bulk and surface phase, surface area, particle size, and optical response of TiO₂ was investigated by X-ray diffraction (XRD), UV Raman spectroscopy, transmission electron microscopy (TEM), BET, and UV-visible diffuse reflectance spectra. It is found that the crystalline phase and phase composition in the bulk and surface region of Nd-TiO₂ calcined at high temperatures can be tuned by changing the amount of Nd₂O₃. Based on the results from XPS, EDX, XRD, and UV Raman spectra, it is assumed that Nd³⁺ ions do not enter the TiO₂ lattice, but highly disperse onto the Nd-TiO₂ particle surface in the form of Nd₂O₃ crystallites. These crystallites inhibit the agglomeration, growth in crystal size, and anatase-to-rutile phase transformation of TiO₂. In the photocatalytic degradation of RhB reaction, Nd-TiO₂ nanoparticles with higher surface area and wider optical response are more reactive in case of the same surface anatase phase. When the mixed phases of anatase and rutile exist in the surface region of Nd-TiO₂, the synergetic effect over surface area and optical response is the important parameter which determines optimal photocatalytic activity.     

Synthesis of carbon coated nanocrystalline porous α-LiFeO2 composite and its application as anode for the lithium ion battery

In this work, we describe for the first time a high surface area nanocrystalline porous α-LiFeO₂-C composite anode material synthesized by a simple molten salt method, followed by a carbon coating process. The synthesized nanocomposite presents an interconnected porous architecture, as was confirmed by field emission scanning electron microscope observations. Transmission electron microscope investigations revealed that amorphous carbon was incorporated into the pores among the nanoparticles and that some nanoparticles were covered by a thin layer of amorphous carbon as well. Electrochemical measurements showed that the carbon played an important role, as it affected both the cycle life and the rate capability of the electrode. The α-LiFeO₂-C nanocomposite electrode delivered a higher reversible capacity and good cycle stability (540 mAh g⁻¹ at 1 C after 200 cycles) compared to the pure α-LiFeO₂ electrode. Good electrochemical performance of the α-LiFeO₂-C nanocomposite electrode could be attributed to the porous conductive architecture among the nanoparticles, which not only has benefits in terms of decreasing the absolute volume changes and increasing the mobility of lithium ions, but also offers conductive pathways along the whole interconnected wall in the structure, which is favourable for the transport of electrons, promotes liquid electrolyte diffusion into the bulk material, and acts as a buffer zone to absorb the volume changes. Our results indicate that α-LiFeO₂-C nanocomposite could be considered as a potential anode material for lithium-ion batteries.     

Evaluation of physico-chemical properties of plasma treated PS-TiO2 nanocomposite film

In this work, we use TiO₂ nanoparticles with average particle size 30 nm and polystyrene for production nanocomposite thin films. After polystyrene was dissolved in toluene, then TiO₂ nanoparticles was added to the solution with different percentage. The obtained solutions were coated on quartz substrate using spin coater. The effect of argon RF plasma (13.6 MHz, with treatment time 30-120 s) on the optical properties, crystallinity, and the surface energy of PS-TiO₂ nanocomposite has been investigated. Some characterization techniques viz., X-ray diffraction analysis (XRD), UV-visible spectroscopy and contact angle measurement were used to study the induced changes on the properties of the treated PS-TiO₂ nanocomposite. Crystalinity and optical properties remained unchanged at the same conditions. Moreover, the surface energy of treated sample varied comparing to the respective untreated samples.     

Effects of defects generated in ALD TiO<Subscript>2</Subscript> films on electrical properties and interfacial reaction in TiO<Subscript>2</Subscript>/SiO<Subscript>2</Subscript>/Si system upon annealing in vacuum

Thin TiO₂ layers grown at 130°C on SiO₂-coated Si substrates by atomic layer deposition (ALD) using TTIP and H₂O as precursors were annealed, and the effects of the annealing temperature on the resulting electrical properties of TiO₂ and the interface properties between a Pt electrode and TiO₂ were examined using transmission line model (TLM) structures. The as-deposited TiO₂ thin film had an amorphous structure with OH groups and a high resistivity of 6×10³Ω-cm. Vacuum annealing at 700 °C transformed the amorphous film into an anatase structure and reduced its resistivity to 0.04Ω-cm. In addition, the vacuum-annealing of the TiO₂/SiO₂ structure at 700°C produced free silicon at the TiO₂-SiO₂ interface as a result of the reaction between the Ti interstitials and SiO₂. The SiO₂ formed on the TiO₂ surface caused a Schottky contact, which was characterized by the TLM method. The use of the TLM method enabled the accurate measurement of the resistivity of the vacuum-annealed TiO₂ films and the characterization of the Schottky contacts of the metal electrode to the TiO₂.     

Preparation of TiO<Subscript>2</Subscript> Nanopowders by Plasma Spray and Characterizations

TiO₂ powders with the range of 10-60 nm were prepared successfully by plasma spray in the self-developed plasma spray equipment. The prepared nanopowders were characterized by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that the prepared TiO₂ nanopowders were the mixture of anatase phase and rutile phase, the main phase was anatase. There were O, Ti, and C elements in powders; Ti element still existed in tetravalent. The photocatalytic degradation of methyl orange indicated that all methyl orange (20 mg/L) can be degraded fully when the addition of prepared TiO₂ nanopowders and illumination time were 1 g/L and 150 min, respectively.     

Properties of TiO2 film prepared from titanium tetrachloride

The properties of TiO₂ film prepared by titanium tetrachloride were investigated with respect to annealing temperatures in terms of phase change, crystallite size, and band gap energy. The TiO₂ film dried at room temperature exhibited an amorphous phase, while films calcined above 281 and at 990°C displayed anatase TiO₂ and a mixture of anatase and rutile, respectively. The TiO₂ film was transformed to an anatase phase through three stages during the annealing processes: (1) removal of water, (2) decomposition of a peroxo group, and (3) amorphous-anatase phase transformation. It was also found that the bandgap energy of TiO₂ film was changed with increasing annealing temperature. This is attributed to the quantum size effect in the range of 475–675°C and to the formation of rutile phase having lower band gap energy than anatase in the range of 675–990°C.     

Ni-TiO2 nanocomposite coating with high resistance to corrosion and wear

Ni-TiO₂ nanocomposite coatings with various contents of TiO₂ nanoparticles were prepared by electrodeposition in a Ni plating bath containing TiO₂ nanoparticles to be codeposited. The influences of the TiO₂ nanoparticle concentration in the plating bath, the current density and the stirring rate on the composition of nanocomposite coatings were investigated. The composition of coatings was studied by using energy dispersive X-ray system (EDX). The wear behavior of the pure Ni and Ni-TiO₂ nanocomposite coatings were evaluated by a pin-on-disc tribometer. The corrosion performance of coatings in 0.5 M NaCl, 1 M NaOH and 1 M HNO₃ as corrosive solutions was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy methods (EIS). The microhardness and wear resistance of the nanocomposite coatings increase with increasing of TiO₂ nanoparticle content in the coating. With increasing of TiO₂ nanoparticle content in the coating, the polarization resistance increases, the corrosion current decreases and the corrosion potential shifts to more positive values.