La_(0.2)Ca_(0.8)MnO_3催化剂活性相的结构和形成机理

利用TG，DTA，XRD和XPS方法研究了La0.2Ca0.8MnO3催化剂的结构和形成机理．样品用La，Ca，Mn混合硝酸盐制备．随着焙烧温度的升高发生了一系列的固相反应，发现氨氧化催化剂催化活性与生成的CaMnO3含量成正比．在900℃制备的含有CaMnO3，La0.575Ca0.425MNO3，Mn2O3和La2O3的混合物是氨氧化最佳催化剂，活性相是CaMnO3，并具有大量的氧空穴.

Studies on preparation, characterization of cobalt(II) phenanthroline and 8-hydroxyquinoline complexes/Y zeolite, and catalytic hydroxylation of phenol

Cobalt(II) phenanthroline and 8-hydroxyquinoline complexes/Y zeolite, denoted as CoPhen/Y and CoOx/Y respectively, were prepared, The formation of the metal complexes mentioned above within the cages of Y zeolite and their crystal structures were determined by elementary analyses, TG-DTA, diffuse reflectance UV-Vis, SEM, BET and XRD methods. The influence of experimental parameters upon phenol conversion and product selectivities was investigated as well.

Synthesis, characterization and catalytic activity for H2O2 decomposition of tetrabasic tungstovanadophosphate heteropoly rare earth element complexes with Dawson structure

Nine tetrabasic tungstovanadophosphate heteropoly rare earth element complexes with Dawson structure were synthesized. Their general molecular formulas are K15H4[Ln . (P2W16VO61)(2)] . xH(2)O(Ln = La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, Yb3+). Their structures and properties were investigated by IR, UV, NMR, ESR, XRD, TG-DTA. The results showed that the series of complexes have the same structure as K-16[Ce(P2W17O61)(2)] . 50H(2)O. At the same time, the catalytic activity of the complexes for H2O2-decomposition was also investigated.

Synthesis of N-(n-octyl)-N'-(10-mercaptodecyl)-4,4'-bipyridinium dibromide and electrochemical behaviour of its monolayers on a gold electrode

A new viologen derivative of N-(n-octyl)-N'-(10-mercaptodecyl)-4,4'-bipyridinium dibromide has been prepared and characterized by elemental analysis, IR, H-1 NMR, MS and TG-DTA. X-Ray photoelectron spectroscopy, cyclic voltammetry and chronoamperometry have been used to characterize the monolayers formed by this compound on the bulk gold electrodes by self-assembly.

铁邻菲咯啉、8-羟基喹啉配合物/Y型分子筛的制备、表征及催化苯酚羟化的研究

制备了铁邻菲咯啉、8-羟基喹啉配合物/Y型分子筛(简记为FePhen/Y,FeO_x/Y).用元素分析,TG-DTA,UV-Vis,IR,SEM,BET,及XRD等方法确定了分子筛笼中金属配合物的生成及其晶体结构,考察了实验参数对苯酚转化率及产物选择性的影响.

间硝基苯甲酸稀土配合物的热分解

用TG-DTA,高温X-射线衍射研究了稀土间硝基苯甲酸配合物LnL_3·nH_2O(n=2,Ln=La→Lu+Y;n=0,Ln=Sc,HL=间硝基苯甲酸)的热分解行为,DSC测定其脱水相变过程中的热力学函数,同时用透射电镜观察了热分解产物的超微性。

对-(二乙氨基)苯基锗倍半氧化物的合成及对体外培养癌细胞的作用

β-羧乙基锗倍半氧化物(Ge-132)的无毒广谱抗癌作用以及潜在的治疗艾滋病的功能~[1～3]促进了Ge-132及其衍生物合成及生物活性研究~[4～6],而对锗原子直接与苯环及其衍生物连接的有机锗倍半氧化物的研究则相对较少.我们曾报道了~[7]p-(二甲氨基)苯基锗倍半氧化物的合成、结构及对癌细胞的作用,p-(二乙氨基)苯基锗倍半氧化物的研究尚未见报道.本文采用改进的方法合成了p-(二乙氨基)苯基锗倍半氧化物(Ge-164).通过元素分析、IP、XPS和TG-DTA确定了组成和结构,观察了它对体外培养人乳腺癌细胞有丝分裂的影响.

铽芳香族羧酸配合物的热分解机理及动力学研究

本文采用TG-DTA-DTG等技术研究了铽羧酸配合物的热分解过程,通过对中间产物进行红外光谱、元素分析、确定了热分解机理。采用三种方法尝试求得了希土羧酸配合物热分解过程的活化能和焓变,发现并总结了其相变过程。

PROPERTIES OF BETA-CARBOXYETHYL-GERMANIUM SESQUIOXIDE AND INTERACTIONS OF IT WITH SOME SUBSTRATES

Three samples of β-carboxyethyl-germanium sesquioxide (Ge-132) have been prepared with different methods. Their IR, Raman, XPS, TG-DTA and FAB-MS spectra are quite different and indicate that they have different degree of polymerization and molecule structures. In the aqeous solution, all of them interaot strongly with fructose, but not with polypeptides such as GSH and GSSG. This faot may be important in understanding the bioactivity of Ge-132.

稀土-锌-还原谷胱甘肽三元配合物的合成及其性质

本文报道LnZn(OH)_2(GSH)_3·3H_2O(Ln=La,Pr,Nd)型三元配合物的合成及其IR,TG-DTA和XPS谱性质,讨论了配合物的结构。

Low temperature synthesis of perovskite oxide using the adsorption properties of cellulose

La-0.8Sr(0).2CoO(3) (LSCO) oxide powder was prepared using the adsorption properties of cellulose. The preparation process was studied by XRD, FTIR, TG-DTA and CO2-TPD techniques. The results of XRD, IR and TG-DTA testified that cellulose could successfully reserve the homogeneity of the solution system to the solid precursor. During the early stage of pyrolysis, cellulose was partially oxidized, and some COO- groups appeared in its texture, which were then complexed with the adsorbed metal ions, and effectively suppressed the aggregation of metal ions. Formation of a pure perovskite and the properties of the powder resulted were found to be significantly influenced by the cellulose to metal nitrate ratio. Also the properties of the resulting powder were greatly influenced by the calcination conditions. If the produced carbon dioxide could not be eluted in time, carbonate would be formed in the bulk. Hence, a high calcination temperature (> 800 degreesC) was needed to acquire a pure phase LSCO. At optimized conditions, nano-crystal LSCO could be obtained at as low as 500 degreesC.

A novel method to synthesize amorphous silica-alumina materials with mesoporous distribution without using templates and pore-regulating agents

In this study, a novel sol-gel method is used to synthesize amorphous silica-alumina materials with a narrow mesoporous distribution and various Si/Al molar ratios without using any templates and pore-regulating agents. During the preparation procedure, only inexpensive inorganic salts were used as raw materials, instead of expensive and harmful alkoxides. The precursor sol was dried at room temperature in a vacuum box kept at 60 mmHg until it began to form the gel. The results of a nitrogen sorption experiment indicate that the synthesized materials with different Si/Al molar ratios have similar mesoporous distributions (within 2-12 nm). Moreover, it was found that the material's pore size distribution remains at a similar value during the heat treatment from room temperature to 550 degreesC. On the basis of the nitrogen sorption, TEM, and AFM characterization results, a formation mechanism of mesopores which accounts for the experimental data is also suggested. This suggested mechanism involves rearrangement of the primary particles during the drying process to form the precursors of the similarly sized mesopores. The synthesized materials were characterized by XRD, thermal analysis (TG/DTA), Al-27 and Si-29 MAS NMR spectroscopy, SEM, TEM, and AFM. The results of Al-27 and 29Si MAS NMR indicate that the distribution of silicon and aluminum in the synthesized materials is more uniform and homogeneous than that in the mixed oxides prepared via the traditional sol-gel method even at high alumina contents. The type and density of the acid sites were studied using pyridine adsorption-desorption FTIR spectroscopy. It was shown that the acidity of the synthesized materials is higher than that of the silica-alumina materials prepared by conventional methods.

异丁烷脱氢制备异丁烯催化剂的研究

Pt-Sn/A1_2O_3负载型双金属催化剂由于其独特的催化性能而被广泛应地用于催化重整工业当中。尽管它对于长链烷烃的脱氢取得较为理想的效果，但用于异丁烷等小分子脱氢却不够理想。Pt-Sn/Al_2O_3负载型双金属催化剂用于异丁烷脱氢，其初活性较高，但对异丁烯的选择性较低，且稳定性较差，易失活。本研究工作就是以Pt-Sn/Al_2O_3负载型双金属催化剂为基础，通过添加碱金属、稀土元素来调变其脱氢性能，一方面提高催化剂的稳定性，另一方面提高对异丁烯的选择性。本文所需要的所有催化剂均是应用传统的共浸法制得。我们首先研究了经碱金属调变的催化剂的脱氢性能。我们发现加入碱金属，尽管催化剂的初活性略有降低，但催化剂对异丁烯的选择性却明显升高，其抗积炭性能也有显著提高。在这三种碱金属当中，K的调变效果最好。我们借助于现代化的测试手段(XRD、XPS、TPR、DTA-TG)对催化剂及其积炭样品进行了表征。结果表明，所有金属组分均以高分散状态存在于载体之上，碱金属钾的加入并没有将离子态的锡还原为金属态。由于K~+是很强的电子施主，它能够减缓活性中心铂的缺电子状态(由于载体效应的存在，铂受载体的拉动效应，它往往以不同程度缺电子状态存在)，从而减缓了活性中心与烃类之间的相互作用，有利于抑制积炭的产生。我们应用DTA-TG研究催化剂的积炭样品发现，碱金属能够抑制了烃类的深度脱氢。碱金属还中和了载体表面的酸性中心，这既抑制了异构化等副反应的发生，提高了对异丁烯的选择性，又抑制了积炭反应的发生。稀土元素对Pt-Sn - K/Al_2O_3催化剂的影响比较复杂。在种稀土元素当中(La、Ce、Pr、Nd、Sm、Eu)，Sm、Ce的调变效果较好，而Eu的调变效果最差。钐的载量不宜太多，以0.30%为宜，太多，一方面有可能将离子态的锡还原成金属态而使催化剂失活，另一方面可能会导致载体晶型有所改变而影响金属组分与载体间的相互作用。TPR结果表明，稀土元素对催化剂的强弱吸附中心的影响是不同的。弱中心上，它作为受电子体，使得铂的缺电子状态加剧，削弱了活性中心与载体之间的相互作用；在强吸附中心上，稀土元素是给电子体，减缓了活性中心铂的缺电子状态，增强了其与载体的相互作用，这两方面共同作用的结果，增强了催化剂的抗积炭能力，提高了催化剂的稳定性。由于铟与锡属于同一周期，且在周期表中处于相临的位置，因此我们考察了铟的不同载量对Pt-In/A1_2O_3催化剂脱氢性能的影响。铟载量跟锡载量相同的情况下，Pt-Sn/Al_2O_3催化剂的活性要比Pt-Sn/Al_2O_3催化剂的活性高，但其对异丁烯的选择性和抗积炭能力却要比Pt-Sn/Al_2O_3催化剂差。另外，随着铟载量的逐渐增加，催化剂的活性逐渐下降，对异丁烯的选择性逐渐升高，异构化逐渐降低。这说明铟在催化剂中起了两方面的作用。首先，它能中和载体表面的酸性中心，再者，对铂活性中心起着一种电子效应。另外我们还考察了碱金属钾对Pt-In/Al_2O_3催化剂的调变作用