La＿xBi＿（2－X）Ti＿4O＿11的合成及相变研究

合成了Ｌａ＿ｘＢｉ＿（２－Ｘ）Ｔｉ＿４Ｏ＿１１系列样品，并完成了它们的喇曼光谱和ｘ射线衍射测量；结果表明，该体系在Ｘ＝１．２经历了一次相变，且相变与最低频声子模随Ｘ的变化有关。Ｌａ＿０．２Ｂｉ＿１．８·Ｔｉ＿４Ｏ＿１１的相变温度为２００℃。初步获得Ｌａ＿２Ｔｉ＿４Ｏ＿１１的结构为正交结构。     

推进剂中阻燃剂TiO_2迁移的ICP－AES研究

本文采用ＩＣＰ－ＡＥＳ法，测定了三基包覆药中阻燃剂组分二氧化钛（ＴｉＯ２）在不同温度和不同时间条件下，向火药基体的迁移。得到了ＴｉＯ２的浓度分布函数，导出了迁移量随老化时间和老化温度而变化的函数关系，并就ＴｉＯ２迁移对包覆火药的贮存寿命的影响作了讨论。进一步得到包覆火药与火药基体具有相同贮存寿命和弹道寿命的结论。     

钒掺杂对Pb2Sr2Nd1.5Ce0.5Cu3O10＋δ（Pb—3222）成相的影响

本着重研究了钒对Ｐｂ－３２２２相成相的影响，当Ｎｄ＾３＋＿／Ｃｅ＾４＋为３：！时，通过钒掺杂简单方便地制备了单相性较好的Ｐｂ－３２２２相样品，本还讨论了钒在Ｐｂ２Ｓｒ２－Ｎｄ１．５Ｃｅ０．５Ｃｕ３Ｏ１０＋δ中的可能位置。     

反散射理论应用于e－H＿2O碰撞

运用反散射方法研究了ｅ－Ｈ＿２Ｏ碰撞。从ｅ－Ｈ＿２Ｏ弹性散射微分截面的实验数据出发，运用反散射方法，ｅ－Ｈ＿２Ｏ相互作用的球平均势已被导出，它是复数的，而且含有非定域的成分。所得的势能给出非常符合实验数据的结果。     

ZnO－Bi＿（2）O＿（3）－Sb＿（2）O＿（3）－BaO系陶瓷的晶界相与抗退降性能

在通常的ＺｎＯ－Ｂｉ＿２Ｏ＿３－Ｓｂ＿２Ｏ＿３系电压敏陶瓷中，加入能构成压敏特性的钡添加剂，发现除已知的Ｂｉ＿２Ｏ＿３和Ｚｎ＿２．３３Ｓｂ＿０．６７Ｏ＿４晶界相以外，还出现新的晶界相，分析表明是固溶有微量其它成分的偏锑酸钡（ＢａＳｂ＿２Ｏ＿６）晶相。同时还发现，ＢａＳｂ＿２Ｏ＿６相是热稳定的，它对改善压敏陶瓷的退降性能起重要作用。通过控制各种添加剂的含量，使晶界相Ｂｉ＿２Ｏ＿３，Ｚｎ＿２．３３Ｓｂ＿０．６７Ｏ＿４和ＢａＳｂ＿２Ｏ＿６之间的数量有适当比例时，压敏陶瓷在长期电负荷作用下和脉冲大电流作用下的抗退降能力都有显著的提高，特别可贵的是反向Ｖ—Ｉ特性的退阵有很大的改善。     

Pb(Zr0.6Ti0.4)O3/YBa2Cu3O7-x双层结构的制备及其特性的研究

我们通过脉冲激光淀积的方法在Ｙ－ＺｒＯ２衬底上原位生长了Ｐｂ（Ｚｒ０．６Ｔｉ０．４）Ｏ３／ＹＢａ２Ｃｕ３Ｏ７－ｘ双层薄膜,在此样品上利用电子探针分析了成分,Ｘ衍射谱证实了两层薄膜为单取向生长,对Ｐｂ（Ｚｒ０．６Ｔｉ０．４）Ｏ３薄膜的铁电性质进行了测试,得到了典型的电滞回线,并对介电常数和损耗角正切值随频率变化进行了测量。     

光催化剂SO2- 4/TiO2和TiO2 的光谱行为比较

用ＩＲ、Ｒａｍａｎ和ＤＲＳ光谱研究了ＳＯ＾２－４／ＴｉＯ２光催化剂和ＴｉＯ２光催化剂的光谱行为差别。结果表明,ＴｉＯ２光催化剂的表面只有Ｌ酸中心,而ＳＯ＾２－４／ＴｉＯ２光催化剂表面既有Ｌ酸中心也有Ｂ酸中心。ＴｉＯ２的硫酸化有效地抑制了晶相转变和晶粒度的增加。与ＴｉＯ２相比,ＳＯ＾２－４／ＴｉＯ２光催化剂的锐钛矿相含量较多、晶粒较小、光谱吸收边蓝移,从而增大了光吸收阈值,增强了光生空穴和电子的氧化     

Bi2Ti4－xTexO11的合成及相变研究

本文合成了系列Ｂｉ２Ｔｉ４－ｘＴｅｘＯ１１样品，拉曼光谱及Ｘ射线衍射谱表明该体系的相转化边界发生在ｘ＝０．５处，Ｂｉ２Ｔｅ４Ｏ１１的压致结构相变的压力为８．２ＧＰａ。本文结果证实了我们过去对Ｂｉ２Ｔｉ４Ｏ１１相变提出的机制     

Bi2Ti4－xTexO11的合成及相变研究

本文合成了系列Ｂｉ２Ｔｉ４－ｘＴｅｘＯ１１样品，拉曼光谱及Ｘ射线衍射谱表明该体系的相转化边界发生在ｘ＝０．５处，Ｂｉ２Ｔｅ４Ｏ１１的压致结构相变的压力为８．２ＧＰａ。本文结果证实了我们过去对Ｂｉ２Ｔｉ４Ｏ１１相变提出的机制     

［（μ－CF＿3CO＿2）＿2Ln（μ－CF＿3HCO＿2）Al（i－Bu）＿2·2THFl＿2（Ln＝Nd，Y）配合物的NMR和X－射线衍射研究

对［μ－ＣＦ＿３ＣＯ＿２）＿２Ｌｎ（μ－ＣＦ＿３ＨＣＯ＿２）Ａｌ（ｉ－Ｂｕ）＿２·ＴＨＦｌ＿２（Ｌｎ＝Ｎｄ，Ｙ）配合物单晶结构的Ｘ－射线分析指出，配合物具有中心对称性，配位中心由两个稀土和两个Ａｌ离子组成，稀土由两个ＴＨＦ和６个ＴＦＡ分子配位形成畸变的三盖三棱柱结构，Ａｌ由两个ＴＦＡＧ和两个ｉ－Ｂｕ配位形成四面体结构。桥连Ａｌ与两个稀土的ＴＦＡ分子的羧基发生歧化加氢，其碳原子由ＳＰ￣２型转变为ＳＰ￣３型．ＮＭＲ研究表明，在ＴＨＦ溶液中，该配合物保持了它在单晶中的配位结构，所不同的是两个ｉ－Ｂｕ在溶液中有两种异构形成，二者间为慢交换过程。     

Synthesis of Different TiO_2 Nanostructures and Their Physical Properties

Titanium dioxide(TiO_2) nanosheet, nanorod and nanotubes are synthesized using chemical vapor deposition(CVD) and anodizing processes. TiO_2 nanosheets are grown on Ti foil which is coated with Au catalyst in CVD,TiO_2 nanorods are synthesized on treated Ti foil with HCI by CVD, and TiO_2 nanotubes are prepared by the three-step anodization method. Scanning electron microscopy shows the final TiO_2 structures prepared using three processes with three different morphologies of nanosheet, nanorod and nanotube. X-ray diffraction verifies the presence of TiO_2. TiO_2 sheets and rods are crystalized in rutile phase, and TiO_2 tubes after annealing turn into the anatase crystal phase. The optical investigations carried out by diffuse reflection spectroscopy reveal that the morphology of TiO_2 nanostructures influencing their optical response and band gap energy of TiO_2 is changed for different TiO_2 nanostructures.     

Carbon-nanodot-coverage-dependent photocatalytic performance of carbon nanodot/TiO_2 nanocomposites under visible light

Carbon nanodots(CDs) with visible absorption band and TiO_2 are integrated to enhance the photosensitivity of TiO_2.The CD/TiO_2 nanocomposites show obvious CD-coverage-dependent photocatalytic performance. The CD/TiO_2 nanocomposites with moderate CD coverge exhibit the highest photocatalytic activity after being irradiated with visible light, which is more excellent than that of TiO_2. Too little CD coverage could result in poor visible light absorption, which limits the photocatalytic performance of CD/TiO_2 nanocomposites. While, too much CD coverage weakens the photocatalytic activity of CD/TiO_2 nanocomposites by restraining the extraction of conduction band electrons within TiO_2 to generate active oxygen radicals and the electron transfer(ET) process from CDs to TiO_2. These results indicate that rational regulation of CD coverage and the realization of efficient ET process are important means to optimize the photocatalytic performance of CD/TiO_2 nanocomposites.     

Importance of ligands on TiO_2 nanocrystals for perovskite solar cells

The fabrication of high-quality electron-selective layers at low temperature is a prerequisite to realizing efficient flexible and tandem perovskite solar cells(PSCs). A colloidal-quantum-dot ink that contains TiO_2 nanocrystals enables the deposition of a flat film with matched energy level for PSCs; however, the selection of ligands on the TiO_2 surface is still unexplored. Here, we systematically studied the effect of the titanium diisopropoxide bis(acetylacetonate)(TiAc_2)ligand on the performance of PSCs with a planar n-i-p architecture. We prepared TiO_2 nanocrystals from TiCl4 and ethyl alcohol with Cl~- ligands attached on its surface and we found that a tiny amount of TiAc_2 treatment of as-prepared TiO_2 nanocrystals in a mixed solution of chloroform and methyl alcohol can enhance PSC power conversion efficiency(PCE)from 14.7% to 18.3%. To investigate the effect of TiAc_2 ligand on PSCs, TiO_2 samples with different TiAc_2 content were prepared by adding TiAc_2 into the as-obtained TiO_2 nanocrystal solution. We use x-ray photoelectron spectroscopy to identify the content of Cl so as to reveal that Cl ligands can be substituted by TiAc_2. We speculate that the improvement in PCE originates from amorphous TiO_2 formation on the TiO_2 nanocrystal surface, whereby a single-molecule layer of amorphous TiO_2 facilitates charge transfer between the perovskite film and the TiO_2 electronic transport layer, but excessive TiAc_2 lowers the PSC performance dramatically. We further prove our hypothesis by x-ray diffraction measurements. We believe the PCE of PSCs can be further improved by carefully choosing the type and changing the content of surface ligands on TiO_2 nanocrystal.     

PbO对V_2O_5/TiO_2催化剂NH_3选择性催化还原NO的影响

基于铅在中国燃煤和MSW焚烧烟气中的特点,采用静态N_2物理吸附、NH_3化学吸附、程序升温表面反应、傅里叶变换红外光谱和催化剂活性评价的方法,研究了PbO对1 wt.%V_2O_5/TiO_2催化剂NH_3选择性催化还原NO的影响.结果表明,PbO使SCR催化剂活性降低.对于燃煤锅炉,PbO对V_2O_5/TiO_2催化剂的影响可以忽略不计;对于MSW焚烧炉,PbO是使V_2O_5/TiO_2催化剂失活的重要铅化合物.Pb覆盖在TiO_2表面上,与V活性位覆盖在TiO_2表面上的方式类似.催化剂的失活主要是由于PbO中和了催化剂表面Brφnsted酸性位的酸性,Brφnsted酸性位对于NH_3的吸附和活化起重要作用.     

FTIR-ATR技术考察TiO2膜对油酸的光催化氧化性能

采用Sol-Gel和PVD法在玻璃、陶瓷、铝片表面制备出TiO2膜,直接将食用油中的主成分油酸用溶剂稀释后均匀涂在膜表面,采用FTIR-ATR技术实现了对膜样品光催化自清洁性能的快速准确评价,并通过测量水的接触角评价了膜的亲水性。结果表明,Sol-Gel法和PVD法制备的TiO2/玻璃膜都具有较好的光致亲水性和光催化降解油酸性能,两者的亲水性没有明显差别,但前者的光催化活性稍优于后者。比较Sol-Gel法制备的TiO2/玻璃、TiO2/陶瓷和TiO2/铝片膜对油酸的光催化降解性能发现,光照3·5h后3个样品的降解率分别为92%,85%和46%,表明基底材料性质对TiO2膜的光催化活性有明显影响,镀在非导电性玻璃和陶瓷表面的TiO2膜比镀在导电性金属铝表面的TiO2膜对油酸有更高的光催化降解能力。     

电子束蒸发TiO2薄膜的光学特性

研究了不同工艺参数条件下，电子束蒸发TiO2薄膜的光学特性。在正交实验的基础上，利用离子束辅助沉积技术，获得了影响TiO2薄膜折射率的主要因素．得到了TiO2薄膜的折射率随氧气分压的关系。对离子氧和分子氧两种情况下TiO2薄膜的折射率进行了比较．得到了TiO2薄膜的折射率与沉积速度的关系，并给出了TiO2薄膜的红外吸收光谱。     

Synchrotron small angle x-ray scattering study of dye-sensitized／-unsensitized TiO2 nanoparticle colloidal solution

The wide-gap semiconductor TiO_2 nanoparticles with and without dye sensitization have been studied by small angle x-ray scattering using synchrotron radiation. Surface properties of the colloidal TiO_2 nanoparticles have been analysed in terms of the surface fractal dimensions (D_s), showing that D_s changes from 3.25 to 2.34 when TiO_2 nanoparticles are sensitized by ATRA (all-trans-retinoic acid), which reveals that the surface of the particles become relatively smooth after dye sensitization. The size distribution of gyration radius of TiO_2 nanoparticles in the colloids M(R_g) has been successfully determined by the Shull－Roess method. The main peak of M(R_g) for the unsensitized TiO_2 colloid is located at 2.1nm, corresponding to a spherical diameter of 5.4nm, and this value for the ATRA sensitized TiO_2 increases to 2.4nm, indicating a spherical diameter of 6.4nm. Such a size enlargement of TiO_2 nanoparticles suggests that there is a coating of ATRA on the TiO_2 surface, supporting the view that a monolayer of the dye has been attached to the surface of the TiO_2 nanoparticle.     

TiO_2 composite electron transport layers for planar perovskite solar cells by mixed spray pyrolysis with precursor solution incorporating TiO_2 nanoparticles

Perovskite solar cells with planar structure are attractive for their simplified device structure and reduced hysteresis effect. Compared to conventional mesoporous devices, TiO_2 porous scaffold layers are removed in planar devices. Then,compact TiO_2 electron transport layers take the functions of extracting electrons, transporting electrons, and blocking holes.Therefore, the properties of these compact TiO_2 layers are important for the performance of solar cells. In this work, we develop a mixed spray pyrolysis method for producing compact TiO_2 layers by incorporating TiO_2 nanoparticles with different size into the precursor solutions. For the optimized nanoparticle size of 60 nm, a power conversion efficiency of 16.7% is achieved, which is obviously higher than that of devices without incorporated nanoparticles(9.9%). Further investigation reveals that the incorporation of nanoparticles can remarkably improve the charge extraction and recombination processes.     

纳米TiO_2薄膜的带宽研究(英文)

利用磁控溅射方法制备了纳米TiO2 薄膜,通过Raman光谱和UV Vis光谱讨论了TiO2 薄膜的带宽随着厚度变化的规律。随着薄膜厚度的增加,TiO2 薄膜的带宽变窄,这是由于纳米薄膜的纳米效应所致     

微波场辅助银掺杂TiO2薄膜光催化降解甲基橙溶液的实验研究

用紫外-可见吸收光谱仪和原子力显微镜(AFM)表征了制备的TiO2和Ag/TiO2薄膜的光谱特性和表面形貌,研究了掺杂改性、微波场辅助作用以及两者相结合的光催化降解方法的薄膜催化活性.结果表明:催化剂的掺杂改性与微波场辅助作用相结合的光催化降解效果优于微波场辅助光催化方法和银掺杂光催化方法.