钛酸盐沸石分子筛催化苯酚羟基化反应的研究

采用Ｘ射线粉末物相分析、红外及紫外漫反射光谱，差热分析，ＮＨ３－脱附法和气体吸附等测试手段研究了Ｔｉ－Ｓｉ沸石ＴＳ－１，ＴＳ－２，Ｔｉ－ＺＳＭ－４８及钛酸钠、钛铝酸钠和钛酸铜分子筛的性能和结构，利用苯酚羟基化反应证明了含有ＴｉＯ，四配位结构单元的沸石分子筛具有催化氧化活性，考察了各种实验条件对苯酚羟基化反应的影响。     

以混合模板剂合成TS-1分子筛及其性能研究

以四丁基溴化铵（ＴＢＡＢｒ）＋四乙基氢氧化铵（ＴＥＡＯＨ，ｎ（ＴＢＡ＋）／ｎ（ＴＥＡ＋）＝１）或以四丙基溴化铵（ＴＰＡＢｒ）＋ＴＥＡＯＨ为模板剂，钛酸四丁酯和正硅酸乙酯为原料，于１７０℃水热合成出ＴＳ１分子筛．对合成的ＴＳ１样品进行了ＸＲＤ，ＦＴＩＲ，ＳＥＭ和ＢＥＴ比表面积分析，证实了样品中钛已进入Ｓｉｌｉｃａｌｉｔｅ１骨架．选择戊烷氧化为探针反应，考察了ＴＳ１的催化活性．结果表明以ＴＥＡＯＨ为碱，合成的样品晶粒较大，达到４～１０μｍ，用氨水和ＴＥＡＯＨ调节反应液的碱度，对晶体的生长和形貌的影响各不相同．文中还就ＴＥＡＯＨ引入的作用进行了讨论．     

SAPO－34分子筛表面酸性质的研究

以水热合成法制备了三个具有不同硅磷铝组成的硅磷酸铝分子筛ＳＡＰＯ－３４样品，采用红外光谱（ＩＲ）和氨法程序升温脱附（ＴＰＤ）两种方法考察了它们的表面酸性质。红外谱图中的３６００ｃｍ－１和３６２１ｃｍ－１谱峰归属于处于ＳＡＰＯ－３４分子筛结构中不同位置的两种桥联羟基（Ｓｉ－ＯＨ－Ａｌ）的振动。ＮＨ３－ＩＲ测定结果显示，这两种羟基具有较强的Ｂ酸特性，并且是分子筛酸性的主要来源；而分子筛具有的Ｌ酸中心的酸性较弱。比较三个样品的ＮＨ３－ＴＰＤ、ＮＨ_３－ＩＲ和骨架组成后发现，ＳＡＰＯ－３４的酸性受其骨架硅含量的强烈影响：当Ｓｉ／Ａｌ摩尔比小于１时，酸性随硅含量增高而变弱；当Ｓｉ／Ａｌ摩尔比大于１时，酸性将随硅含量增高而变强。     

硅源及晶化时间对SAPO-5分子筛结构及性质的影响

分别以硅凝胶和正硅酸乙酯为硅源，通过改变晶化时间合成了系列ＳＡＰＯ５分子筛．用ＸＲＤ，ＭＡＳＮＭＲ和ＳＥＭ对分子筛的结构和形貌进行了表征．结果表明，以硅凝胶为硅源时，凝胶中的铝有３种面体配位状态．加热晶化很容易使凝胶转化为ＳＡＰＯ５分子筛，合成物的晶形更加规则．在４８ｈ内，延长晶化时间有助于硅进入分子筛骨架，使残余的Ａｌ２Ｏ３·Ｈ２Ｏ进一步反应，使骨架硅和铝的面体配位环境更加对称；超过４８ｈ后，硅开始游离出分子筛骨架，并使部分ＳＡＰＯ５转化为ＳＡＰＯ３４．以正硅酸乙酯为硅源时，硅和铝的反应活性均较低，凝胶中ＡｌＰＯ４及Ａｌ２Ｏ３·Ｈ２Ｏ的量均比四面体配位铝的量大．只有当晶化时间超过４８ｈ时，反应物中Ａｌ２Ｏ３·Ｈ２Ｏ才能完全转化．在此反应体系中，延长晶化时间有助于ＳＡＰＯ５的生成，使分子筛骨架硅的取代量更大，晶形更加规则，骨架铝的对称性更好．     

双模板剂法控制SAPO－34分子筛的晶粒尺寸

分别在ＮＥｔ＿３，ＴＥＡＯＨ和ＴＥＡＯＨ－ＮＥｔ＿３双模板剂存在下合成了磷酸硅铝分子筛ＳＡＰＯ－３４．考察了模板剂的组成对ＳＡＰＯ－３４的晶粒尺寸、比表面、热稳定性和对甲醇转化反应催化性能的影响。实验表明，采用ＴＥＡＯＨ－ＮＥｔ＿３双模板剂法，能有效地控制ＳＡＰＯ－３４的晶粒尺寸，以微量的ＴＥＡＯＨ与ＮＥｔ＿３为双模板剂合成的大晶粒ＳＡＰＯ－３４分子筛，对甲醇转化产物和烯烃的选择性有显著提高     

大孔富硅沸石分子筛的制备

大孔富硅沸石分子筛的制备Ｆｒｅｙｈａｒｄｔ等研究人员以一种有机金属化合物［（Ｃｐ＊）２ＣＯ）ＯＨ］作结构定向试剂，成功地研制出一种由十四个Ｔ－原子环形成的大孔径富硅沸石分子筛，其孔径为７５Ａ，孔体积为９９０Ａ３，这种大孔沸石分子筛不仅具有显著的热稳定...     

CdAPO-5的合成、结构及催化性能(Ⅱ)──有机模板剂与金属离子半径大小对晶相形成的影响

探讨了几种不同有机模板剂（二环己胺、二正丁胺、乙二胺、环己胺、ＴＥＡＯＨ）对ＣｄＡＰＯ－５分子筛晶相形成的影响,以及金属离子（Ｍｎ＋）半径大小对取代ＡｌＰＯ４－５分子筛骨架中Ａｌ３＋离子而形成ＭＡＰＯ－５分子筛晶体的影响。结果表明,ＴＥＡＯＨ是合成ＣｄＡＰＯ－５分子筛较合适的有机模板剂,合适形成金属磷酸铝分子筛的Ｐｏｕｌｉｎｇ半径比（ｒｎ＋Ｍ／ｒ２－Ｏ）可大于０．７３。     

以混合模板剂合成TS—1分子筛及其性能研究

以四丁基溴化铵（ＴＢＡＢｒ）＋四乙基氢氧化铵（ＴＥＡＯＨ，ｎ（ＴＢＡ＾＋）／ｎ（ＴＥＡ＾＋）＝１）或以四丙基溴化铵（ＴＰＡＢｒ）＋ＴＥＡＯＨ为模板剂，钛酸四丁酯和正硅酸乙酯为原料，于１７０℃水热合成出ＴＳ－１分子筛。对合成的ＴＳ－１样品进行了ＸＲＤ，ＦＴ－ＩＲ，ＳＥＭ和ＢＥＴ比表面积分析，证实了样品中钛已进入Ｓｉｌｉｃａｌｉｔｅ－１骨架。选择戊烷氧化为探针反应，考察了ＴＳ－１的催化活性。结果表明以     

［Ru_6（CO）_（18）］~（2－）在NaX分子筛超笼中的合成和表征

在ＮａＸ分子筛超笼中通过ＲｕⅢ（ＮＨ３）６同ＣＯ＋Ｈ２反应合成了［Ｒｕ６（ＣＯ）１８］２－原子簇阴离子．原子簇阴离子上的羰基配体在氢气存在时具有一定的１３ＣＯ同位素交换活性．ＥＸＡＦＳ的数据表明，８０─９０％的钌原子在ＮａＸ分子筛中以［Ｒｕ６（ＣＯ）１８］２－的方式存在．分子筛笼中的原子簇阴离子在氧化气氛下解离成单核钌羰基物种Ｒｕ１（ＣＯ）２，两者的结构在氧化（Ｏ２）及还原（ＣＯ＋Ｈ２）条件下可以进行可逆转化．     

CuZSM-5分子筛上苯酚羟化制苯二酚

在Ｎａ２Ｏ－ＳｉＯ２－ＣｕＯ－Ｈ２Ｏ体系中以１５％ＴＰＡＢｒ－８５％ＨＭＤＡ为模板剂合成了ＣｕＺＳＭ－５分子筛，并用ＸＲＤ，ＩＲ及ＳＥＭ等方法进行了表征，考察了ＣｕＺＳＭ－５分子筛催化苯酚与过氧化氢的羟化活性，研究了催化剂用量、反应温度、反应时间及ｎ（ＰｈＯＨ）／ｎ（Ｈ２Ｏ２）等对羟化活性的影响．     

Synergistic effects of CdS in sodium titanate based nanostructures for hydrogen evolution

Synergistic effect of CdS decorated sodium titanate nanostructures showed enhanced H₂ production abilities. The confinement effect and synergistic effect of decorated CdS inside the sodium titanate nanotubes are investigated.     

由钛酸盐纳米带水热制备锐钛矿型TiO2纳米带

研究了水热处理具有层状结构的钛酸钠纳米带或钛酸纳米带转化为锐钛矿型TiO₂的制备过程、难易程度和相转化机理. 实验结果表明, 当水热反应温度和时间分别在160 ℃ 和24 h以内, 钛酸钠纳米带很难完全转化为锐钛矿型TiO₂, 若升高反应温度并延长反应时间, 则可制得纯的锐钛矿型TiO₂, 但纳米带形貌被严重破坏; 当水热反应温度和时间分别为160 ℃ 和16 h时, 1次酸洗的钛酸纳米带能够完全转化为锐钛矿型TiO₂, 若钛酸纳米带经过3次强酸浸泡, 则在160 ℃下相转化时间就会缩短到12 h, 所有钛酸纳米带在转化为TiO₂后的形貌仍为纳米带, 但经3次酸浸后生成的TiO₂纳米带表面更光滑. 讨论了钛酸钠纳米带或钛酸纳米带转化为锐钛矿型TiO₂的相转化机理.     

TiO2 nanotube, nanowire, and rhomboid-shaped particle thin films fixed on a titanium metal plate

Titanium dioxide thin films having various nanostructures could be formed by various treatments on sodium titanate nanotube thin films approximately 5 μm thick fixed on titanium metal plates. Using an aqueous solution with a lower hydrochloric acid concentration (0.01 mol/L) and a higher reaction temperature (90 °C) than those previously employed, we obtained a hydrogen titanate nanotube thin film fixed onto a titanium metal plate by H⁺ ion-exchange treatment of the sodium titanate nanotube thin film. Calcination of hydrogen titanate nanotube thin films yielded porous thin films consisting of anatase nanotubes, anatase nanowires, and anatase nanoparticles grown directly from the titanium metal plate. H⁺ ion-exchange treatment of sodium titanate nanotube thin films at 140 °C resulted in porous thin films consisting of rhomboid-shaped anatase nanoparticles.     

Plate, wire, mesh, microsphere, and microtube composed of sodium titanate nanotubes on a titanium metal template

Sodium titanate nanotube/titanium metal composites were synthesized by hydrothermal treatment of titanium metals with various morphologies such as plate, wire, mesh, microsphere, and microtube at 160 degrees C in aqueous NaOH solution and by the subsequent fixation treatment by calcination at 300 degrees C. The surface of the composite was covered with sodium titanate nanotubes with a diameter of approximately 7 nm, and the core part of the composite was titanium metal phase. The raw titanium metal acts as a template or a morphology-directing agent of micrometer size or more to arrange the nanotubes as well as a titanium source for the formation of nanotubes. The concentration of titanium species increases in the reaction solution as the dissolution of titanium metal is accelerated by the reaction between titanium and OH-. Furthermore, with an increase in concentration of titanium species in the reaction solution, the titanium species are re-precipitated as sodium titanate nanotubes onto the titanium metal. Titanium metal with a large surface area and volume can form sodium titanate nanotubes on the surface of the titanium metal, though titanium metal with a small volume and surface area tends to dissolve with the hydrothermal treatment. Even in the synthesis using titanium metal with a small volume and surface area, sodium titanate nanotubes are formed and cover the surface of the titanium metal by adding another titanium metal as a source of titanium species in the reaction solution.     

Preparation of sodium titanate nanotubes modified by CdSe quantum dots and their photovoltaic characteristics

Sodium titanate nanotubes have been prepared and modified chemically with CdSe quantum dots (QDs) using bifunctional modifiers (HS-COOH). Their photovoltaic characteristics have also been studied. The results indicate that the surface photovoltage response of nanotubes extends to the visible light region, and the intensity of surface photovoltage is enhanced after modification with CdSe QDs. The field-induced surface photovoltage spectroscopy (FISPS) shows that sodium titanate nanotubes have different photovoltaic response before and after modification. That is, the surface photovoltaic re-sponse of pure sodium titanate nanotubes increases with the enhancement of positive applied bias and decreases with the enhancement of negative applied bias. Meanwhile, the surface photovoltaic re-sponse of CdSe modified sodium titanate nanotubes is different from that of the pure sodium titanate nanotubes. The whole spectrum increases with the enhancement of applied bias at the first stage. However, when the applied bias reaches a certain value, the surface photovoltage response keeps in-creasing in some spectrum regions, while decreasing in other spectrum regions. This novel phe-nomenon is explained by using an electric field induced dipole model.     

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纳米管钛酸钠及其衍生物是一种新的纳米材料，具有特殊的结构和性质，在电致发光、蓄电池电极、吸附和离子交换材料方面有着广泛的应用前景。本文综述了纳米管钛酸钠的组成、结构、形成机理，介绍了它及其衍生物的特性和功能的研究现状。     

硫掺杂钛酸(盐)纳米管的表征与可见光光催化活性

以二硫化钛为钛源和硫源,通过与NaOH水热反应成功制备了硫掺杂钛酸(盐)纳米管。 采用X射线衍射、高分辨透射电子显微镜、扫描电子显微镜、扩展X射线吸收精细结构(EXAFS)和X光微区分析等手段对所制备的硫掺杂钛酸(盐)纳米管的结构、形貌、硫掺杂状态和掺杂量进行了表征,并以可见光光催化氧化乙醇反应为探针,采用原位气相色谱技术研究了硫掺杂钛酸纳米管的可见光光催化活性;结果表明,S原子以S2-形式取代了钛酸纳米管骨架中O原子的位置, 有效实现了硫掺杂;硫掺杂钛酸(盐)纳米管壁厚平均尺寸为2.9 nm,管径平均尺寸为9.7 nm。 可见光光催化氧化乙醇反应结果表明,掺硫钛酸纳米管在极低的掺硫量条件下,表现出比未掺杂的二氧化钛纳米管具有更高的可见光光催化活性。     

表面改性对片状锌粉分散稳定性的影响

采用物理化学法,将实验室自制锌粉分别添加钛酸酯偶联剂、硅烷偶联剂和十二烷基苯磺酸钠进行表面改性,利用沉降法测试高度研究改性前后锌粉的分散稳定性。 结果表明,不同种类、不同浓度的表面改性剂对锌粉的分散稳定性有较大的影响;其中,经1.0%钛酸酯偶联剂改性后锌粉的分散稳定性有了明显的改善,与进口粉的分散稳定性接近。     

Nanotube formation from a sodium titanate powder via low-temperature acid treatment

Through structure-monitoring of nanotube formation from a lamellar sodium titanate, the present work explicitly elucidated the structure of the titanate nanotubes obtained from hydrothermal treatment of TiO(2) with NaOH. A new compound of an orthorhombic lepidocrocite-type sodium titanate was synthesized from calcination of a solid-state mixture of TiO(2) anatase and Na(2)CO(3) powders followed by hydrothermal treatment with NaOH. By treating with acid at 25 degrees C for Na(+) exchange with H(3)O(+), the titanate compound exfoliated and then proceeded with sheet-scrolling to form nanotubes, which had a structure and morphology very close to those of the nanotubes derived from NaOH treatment on TiO(2). During the low-temperature acid treatment, the lepidocrocite-type titanate is transformed from the orthorhombic C-base-centered symmetry to the body-centered symmetry. This transformation, accompanied by a size-contraction of TiO(6)-octahedron units, was critical for the formation of nanotubes. The present work provides direct evidence, for the first time, that the widely reported TiO(2)-derived titanate nanotubes can be obtained at low temperatures by scrolling the sheets exfoliated from the orthorhombic lepidocrocite-type titanate.     

Apatite-forming ability of titanium compound nanotube thin films formed on a titanium metal plate in a simulated body fluid

We compared the apatite-forming ability of a sodium titanate nanotube thin film, an anatase-type titanium dioxide nanotube thin film, and a silver nanoparticle/silver titanate nanotube nanocomposite thin film, in simulated body fluid. The ability of the silver nanoparticle/silver titanate nanotube nanocomposite thin film is slightly higher than that of the anatase-type titanium dioxide nanotube thin film and significantly higher than that of the sodium titanate nanotube thin film. The high ability of the silver nanoparticle/silver titanate nanotube nanocomposite thin film is a newly observed phenomenon, which is probably due to the crystal structure of silver titanate – specifically, to the surface atomic arrangement, the large amount of Ti–OH formed on the nanotube surface, or both. The anatase-type titanium dioxide nanotube thin film and the silver nanoparticle/silver titanate nanotube nanocomposite thin film may have bright prospects for future use in implant materials such as artificial joints. The silver nanoparticle/silver titanate nanotube nanocomposite thin film is particularly promising for its antibacterial properties.