高能机械球磨法制备V-Ti-O超细微粒催化剂

负载型V2O5/TiO2氧化物催化剂因具有优良的催化性能而广泛地用于烃类选择性氧化[1,2]和氮氧化物选择性催化还原(SCR)[3]. 迄今,所研究的负载型V2O5/TiO2氧化物催化剂大多是采用浸渍法制备的[2,4～6],通过调整催化剂的组成[2,5]、引入适当的助剂组分[2,6]和选择适宜的反应操作条件[2,5]可进一步优化其催化性能.     

均分散球形氧化铕超细微粒的制备和表征

采用尿素分解法制备了均分散球形Eu(OH)CO~3·H~2O超细沉淀粒子,进一步在空气中750℃下焙烧4h,得到了均分散球形氧化铕超细微粒。考察了各种反应条件的影响,获得了最佳的制备条件。用XRD,IR,TEM,TG以及比表面测定等手段对样品进行了表征。     

吡咯俘精酸酐的图像光存储特性

对一种新型可用于可擦重写光存储的有机光致变色材料——吡咯俘精酸酐，测定了它的光致变色双稳态吸收光谱，呈色态的吸收峰在635nm，无色态的吸收峰在385nm。利用其双稳态特性，在吡咯俘精酸酐／PMMA薄膜上实现了图像光存储。所存储的图像对比度高，用普通相机在自然光下即可直接读出。在膜上存储的图像在室温下暗处保存6个月未见消退，估计此条件下保存期可以年计。     

一类完全非线性椭圆型方程粘性解的比较原理

讨论一类带有非局部积分项的完全非线性椭圆型方程半连续粘性解的比较原理，这类方程源自带跳跃的扩散过程，在随机控制，金融数学中有广泛而重要的应用。     

SrTi1-xMgxO3-δ钙钛矿型氧化物催化剂甲烷氧化偶联反应性能的研究

The structure and catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Temperature-programmed desorption (O₂-TPD) methods. It has been shown that doping Mg²⁺ cations to the B site of SrTi_1-xMg_xO_3-δ perovskite-type catalysts results in the formation of oxygen vacancies in the lattices of oxide cata-lysts. With increasing the amount of Mg²⁺ doped in the B site of SrTi_1-xMg_xO_3-δ, methane conversion and C₂ selectivity first increase and then decrease remarkably. The SrTi_1-xMg_xO_3-δ catalyst with x=0.1 has the highest methane conversion and C₂ yield. It is suggested that the oxygen vacancies produced by Mg²⁺ cations doping are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi_1-xMg_xO_3-δ catalysts are the main active species for OCM reaction. However, the over high content of the adsorbed oxygen species on the surface results in the complete oxidation of methane. Introducing water steam into feedstock can improve the catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for OCM reaction at lower temperature. The SrTi_0.9Mg_0.1O_3-δ catalyst has the methane conversion of 28.0 % with C₂ hydrocarbons selectivity of 36.8 % under reaction temperature of 550 ℃.     

MoO3-SnO2相互作用的研究

用沉淀法、浸渍法和机械混合物焙烧法制备了三组MoO_3-SnO_2催化剂。XDR, IR和ESR等研究表明: MoO_3-SnO_2之间存在明显的相互作用, 两组份间发生电子迁移现象, 导致Mo(Ⅵ)→Mo(Ⅴ)的价态变化, 产生pKa≤+3.3的表面酸位和甲醇选择氧化活性位。制备方法对这种相互作用以及样品的催化性能有明显影响。沉淀法所得样品中MoO_3可溶于SnO_2形成固溶体; 浸渍法则可发生钼离子向SnO_2体相的扩散; 机械混合物焙烧法在一定MoO_3含量下, MoO_3可在SnO_2表面形成近似单层分散。红外光谱中950 cm~(-1)的新吸收谱带可归因于表面上Mo(Ⅴ)=0振动。表面Mo(Ⅴ)位可能是催化剂表面酸位和甲醇氧化的活性中心。没有发现催化剂中Sn~(4+)价态有明显变化。     

Design and Synthesis of a Selective Chemosensor for Zn^2＋

A hydroxyl substituted phenolic Schiff base 1, used as sensor for detection of Zn^2＋, was synthesized and investigated. It was found that a strong fluorescence emission was observed when 1 bound to Zn^2＋ in acetonitrile, whereas no fluorescence emission was detected when 1 bound to other metal ions （Fe^2＋, Co^2＋, Ni^2＋, Cu^2＋, Cd^2＋, Hg^2＋, Mg^2＋, Pb^2＋, Ca^2＋, Ba^2＋, Sr^2＋） except for Mg^2＋, for which a weak fluorescence emission was detected in the same condition. Competition experiment showed that no obvious interference was observed in its fluorescence while 1 performed the titration with Zn^2＋ in the different mixtures of metal ions. To understand the site where Zn^2＋ coordinated to the ligand and the mechanism of binding, three other hydroxyl substituted phenolic Schiff bases 2-4 were synthesized and their binding reactions with Zn^2＋were also investigated.     

Ni2+在γ-Al2O3上的分散状态及负载型Ni/γ-Al2O3催化剂的α-蒎烯加氢活性

用X-射线衍射(XRD)、紫外-可见漫散射光谱(UV-Vis DRS)、程序升温还原(TPR)、CO化学吸附和微反测试等方法研究了Ni²⁺在γ-Al₂O₃上的分散状态和负载型Ni/γ-Al₂O₃催化剂的α-蒎烯加氢催化活性。结果表明，当Ni²⁺负载量远低于其在γ-Al₂O₃载体表面分散容量时，Ni²⁺优先嵌入载体表面四面体空位，随着Ni²⁺负载量的增加，嵌入载体表面八面体空位Ni²⁺的比例增大。由于八面体Ni²⁺易被还原为金属态Ni⁰，NiO/γ-Al₂O₃样品的还原度随Ni²⁺负载量的增加而大幅度地增加，经氢还原所得Ni/γ-Al₂O₃催化剂的CO吸附量和α-蒎烯加氢催化活性大幅度增加。对La₂O₃助剂的作用进行了研究，结果表明分散在γ-Al₂O₃上的La³⁺物种可阻止Ni²⁺嵌入γ-Al₂O₃表面四面体空位，增大了八面体Ni²⁺物种所占比例，提高了催化剂的还原度，故Ni-La₂O₃/γ-Al₂O₃催化剂催化活性高于Ni/γ-Al₂O₃催化剂。