A novel catalyst of silicon cerium complex oxides for selective catalytic reduction of NO by NH_3

A series of CeO2/SiO2 and SixCe1–xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET, XRD, SEM and NH3-TPD techniques. The effects of reaction temperature, CeO2/SiO2 loadings and Si/Ce molar ratio on the granular catalysts for NO selective catalytic reduction with ammonia (NH3-SCR) were studied. Results indicated that both CeO2/SiO2/ATS and CeO2/ATS catalysts showed the same ac...

Synthesis of monodispersed nanosized CeO_2 by hydrolysis of the cerium complex precursor

A cerium-triethanolamine complex was obtained by the reaction of cerium(III) nitrate and triethanolamine in ethanol solution. Spontaneous oxidation of cerium(III) to cerium(IV) by oxygen occurred during the reaction. The complex was crystalline and soluble in water. Nanosized ceria (CeO2) particles could be prepared via hydrolysis of the complex in aqueous solution, and the extent of agglomeration of particles increased with the increase in temperature for hydrolysis. Under the low temperature of 25 oC, mon...

Synthesis and Characterization of Tetravalent Cerium Complexes with p-Tert-butylcalix[n]arenes (n=4, 6, 8)

Three Ce 4+ complexes Ce(p tert butylcalixarene)·(dmf) 4·H 2O (complex A), Ce(p tert butylcalixarene) 2·(dmf) 10 (complex B) and Ce(p tert butylcalixarene)·(dmf) 4 (complex C) were prepared from N,N dimethylforamide (dmf) solution of Ce(NO 3) 3. Their thermal stability, optical properties and coordination features were investigated with thermogravimetric and differential thermal analysis, ultraviolet and visible spectrophotometer, fluorescence spectrophotometer, infrared spectroscopy, and 1H NMR spectrometer. In the solvents of C 6H 6, 1,2 dichloroethane and dmf, complexes A and B can exhibit a ligand to metal charge transfer transition lying in ca. 20000 cm -1 in the electronic spectra. Complex A displays a dimeric structure in C 6D 6 solution. Ce 4+ ions in the complexes are coordinated by phenolic groups of the ligands, oxygen atoms of dmf molecules, and / or OH - ions.

Synthesis,Crystal Structure and Optical Properties of a Cerium(Ⅳ) Complex with Chelidamic Acid

A new cerium complex, （C7H8）[Ce（C7H3NO5）2（H2O）3]·2H2O or （C7Hs）[Ce（HChel）2· （H2O）3]·2H2O （1, H3Chel = 4-hydroxypyridine-2,6-dicarboxylic （chelidamic） acid）, has been prepared by the hydrothermal reaction, and its crystal structure was determined based on single-crystal diffraction data. Compound I crystallizes in monoclinic, space group P21/c with a = 12.4267（9）, b = 10.8195（7）, c = 19.5650（13）A, β = 92.898（3）°, V = 2627.2（3） A^3, Dc = 1.733 g/cm^3, Z = 4, Mr = 685.55, μ = 1.809 mm^-1, λ（MoKa） = 0.71073A and F（000） = 1372. The final R = 0.0455 and wR = 0.1984 for 5983 observed reflections with I 〉 2σ（I）, and R = 0.0490 and wR = 0.2053 for all data. Complex 1 contains one cerium ion, two chelidamic acid ligands, three coordinated water molecules, one discrete toluene molecule, and two discrete water molecules. The Ce（IV） ion is nine-coordinate with the coordination polyhedron made up of four oxygen atoms and two nitrogen atoms from two tridentate chelating chelidamic acid ligands, and three coordinated water molecules. A three-dimensional network is formed by the H-bonds. Moreover, optical properties are investigated and the results show that this complex has sharp optical absorption at 221,396 and 571 nm but no marked fluorescent emission.

Catalytic performance of cerium iron complex oxides for partial oxidation of methane to synthesis gas

The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.

Synthesis, Crystal Structure and Magnetic Behaviour of Three Dimensional Iron-Cerium Cyanide Bridged Bimetallic Assembly

The complex with the formula [CeFe(CN)(6)(H2O)(3)]. 2H(2)O was synthesized and structurally characterized. It crystallizes in hexagonal, space group P3, a = 0.75320(10) nm, b = 0.75320(10) nm, c = 1.4374(3) nm, gamma = 120 degrees, V = 0.7062(2) nm(3), Z = 3, Be = 3.048 Mg .m(-3), F(000) = 606, mu = 6.346 mm(-1), T = 293(2) K, R-1 = 0.0169, wR(2) = 0.0459. The structure is a three-dimensional network containing open channels formed by the nine-coordinated CeN6(H2O)(3) groups and octahedral FeC6 groups through the cyanide linkages. Magnetic susceptibility measurements in the temperature range of 5.1 similar to 300 It show an antiferromagnetic interaction between the Ce3+ and Fe3+ ions.

复配催化剂催化癸二酸二异辛酯的合成研究

以癸二酸和异辛醇为原料,硫酸高铈和硫酸氢钠为复配催化剂,催化合成了癸二酸二异辛酯。通过单因素实验,分别考察了催化剂的复配比例、使用当量、癸二酸与异辛醇的摩尔比、反应时间等对提高酯化转化率的作用。实验数据表明,复配的催化剂催化活性更高,当复配催化剂中硫酸高铈和硫酸氢钠质量比为2∶1,催化剂用量为4%(以癸二酸计),酸醇摩尔比为1∶1.4,反应时间为6.5h时,酯化率可达94.1%。

Crystal Structure of Quaternary Mixed Anion Complex of Labthanide [Ce(CH_3COO)_2(NO)_3(phen)]_2

[Ce(CH3COO)2(NO3) (phen)]2, Mr=1000. 84. The crystal is monoclinic, lattice type C-centered, space group C2/m, with a=15. 444 (6), b= 12. 273(5), c=12. 776(5) A, β= 131. 89(2)°, Z= 2, Dc= 1, 844 g/cm3, μ(MoKa)=25. 69 cm-1, F(000)=980. 00, V= 1802 (1 ) A, R=0.024, Rw=0. 032. Themolecule of the complex is a dimer with C2h symmetry and the molecular center lies onthe special position 2/m. The Ce(Ⅲ) ion is nine-coordianted to one bidentate nitrategroup, five oxygen atoms of acetates and two nitrogen atoms of 1, 10-phenanthroine(phen).

Synthesis and Crystal Structure of Rare Earth Complex withCiprofloxacin

The complex of rare earth with ciprofloxacin has been synthesized and characterized by means of x-ray single crystal diffraction. The structure features of the complex are decribed.

Synthesis and Structure of a Polymeric Complex [Ce(bphsb)_2(NO_3)_3]_n

Polymeric cerium nitrate complex with 1,4 bis(phenylsulfinyl)butane (bphsb) [Ce(bphsb) 2(NO 3) 3] n (1) was synthesized and characterized. The crystal structure of the complex indicated that the ligand bphsb and cerium(Ⅲ) ion form a polymeric double bridge chain complex involving 18 membered macrometallocycles. Each cerium ion is coordinated by ten O atoms in a distorted 4,4 bicapped square antiprism. In the complex the disulfoxide ligand acts as bis monodentate O ligand bridging metal centers.

溶剂热法制备铜铈基复合催化剂及其催化氧化CO研究

采用溶剂热法,以尿素为沉淀剂合成铜铈复合前驱体,通过高温焙烧处理,制备出铜铈复合氧化物催化剂。通过优化铜铈组分配比,考察铜含量对铜铈复合氧化物催化效果的影响,获得催化剂最佳配伍,该复合催化剂在140℃条件下,CO脱除效率超过99%,表现出高效的催化氧化CO性能。在此基础上,通过掺入锰和锆元素,提升氧化铜在氧化铈中的分散程度,更有利于稳定催化剂的结构。

含有刚柔混合多羧酸配体的新型稀土配位聚合物[Ce(pydc)(Hglu)]_n的水热合成、结构和性质

近年来,设计合成新型的金属-有机配位聚合物受到了人们的青睐,由于它们在结构上的多样性导致了它们在磁性、催化、电子导体等领域具有广泛的潜在应用。因此,在设计合成这些配合物的过程中,金属和配体的选择对其结构性质都会产生很大的影响。其中,在金属选择中,我们发现具有高配位数的稀土元素有助于合成结构新颖的配位聚合物。

岩藻聚糖硫酸酯寡糖-Ce(Ⅳ)配合物水解胶原蛋白的研究

对岩藻聚糖硫酸酯寡糖．铈配合物的制备及其对胶原蛋白的水解活性进行了研究。通过酸水解得到不同分子量的岩藻聚糖硫酸酯寡糖F1（MW〉5ooo），F2（MW1000-500），F3（MW〈1000），小分子的F3与Ce（Ⅳ）的配合效果最好，且水解胶原蛋白的活性高。通过实验确定了岩藻聚糖硫酸酯寡糖F3与Ce（Ⅳ）的配合条件以及F3-Ce（Ⅳ）配合物对胶原蛋白的最佳水解条件。

海藻酸铈配合物对毒死蜱胁迫下菠菜叶片抗坏血酸-谷胱甘肽循环的影响

以菠菜(Spinacia oleracea L.)为材料,研究了毒死蜱胁迫下海藻酸铈配合物对菠菜叶片抗坏血酸-谷胱甘肽循环的影响。结果表明,在毒死蜱胁迫下,菠菜叶片中H2O2积累量比对照明显增加,非酶促抗氧化物质-抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量明显降低,抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、脱氢抗坏血酸还原酶(DHAR)和单脱氢抗坏血酸还原酶(MDAR)的活性明显升高。在毒死蜱胁迫下,喷施不同浓度的海藻酸铈配合物使菠菜叶片中的H2O2积累量减少,AsA和GSH含量升高,APX、GR、DHAR和MDAR等抗氧化酶活性也有所提高,缓解了毒死蜱胁迫。试验表明,适宜浓度的海藻酸铈配合物处理可使菠菜叶片对毒死蜱胁迫有一定的缓解作用。

壳寡糖与镧、铈配合物的合成、表征及应用

合成了壳寡糖 镧和壳寡糖 铈配合物,用红外光谱和紫外光谱进行了表征,并证实了氮 金属(N-M)键的形成,元素分析证实配合物中各元素C∶H∶N∶La或Ce的原子个数比分别接近于24∶44∶4∶1,即相当于配位数为4。壳寡糖 镧和壳寡糖 铈较未配位的镧或铈具有更强的催化氧化能力。配合物除去废液中磷[(PO)43-]的效果比未配位的镧和铈提高10%。配合物可提高蔬菜、水稻种子的发芽率,促进作物的营养生长,提高水稻产量3.3%,提高黄瓜产量12%～15%,对十字花科蔬菜的病毒有一定的抑制作用。

铈配合物与人血清白蛋白相互作用的研究

在生理条件(pH=7.4)下,利用荧光光谱和紫外光谱探讨了华法灵铈与人血清白蛋白(HSA)的相互作用。根据荧光和紫外光谱可知,华法灵铈配合物对人血清白蛋白荧光产生猝灭作用,其猝灭方式为静态猝灭。并通过Stern-Volmer方程等,计算出了配合物与人血清白蛋白的静态猝灭常数、结合常数和结合位点数。根据一系列热力学参数ΔH,ΔS,ΔG的相对大小,确定出配合物与人血清白蛋白的主要作用力类型为静电作用力。且用同步荧光法讨论了华法灵铈对HSA构象的影响。

三足七齿Schiff碱铈(Ⅲ)双核配合物的晶体结构和性质研究

制备了Schiff碱型三足体配体H3Brapi,通过溶剂热方法合成了Ce(Ⅲ)的双核配合物[Ce(Brapi)]2·2DMF,利用元素分析、红外光谱、紫外光谱和荧光光谱等进行了表征,并用X-射线单晶衍射测定了其晶体结构,结果表明,配合物晶体属单斜晶系,P21/n空间群,a=1.1667(3)nm,b=1.34829(3)nm,c=2.0869(5)nm,β=96.314°,Z=2,V=3.2630(14)nm3,Dc=1.849Mg·m-3,R1=0.0359,wR2=0.1036。2个配体桥联2个金属形成一种具有反演对称性的夹心式双核结构,其中每个Ce(Ⅲ)的配位环境N4O4都是一种四方反棱柱多面体,Ce-Ce距离为0.3971nm。在2～300K范围内测定了配合物的变温磁化率,结果表明,在配合物中Ce髥离子间存在反铁磁性相互作用。荧光光谱分析表明,配合物的荧光属于L*-L跃迁的发光类型。

以乙酸为模型反应物的Ti-Ce复合氧化物湿式氧化催化剂的研制

Ti Ce complex oxide catalysts for catalytic wet air oxidation of acetic acid as model reactant were prepared by coprecipitation and impregnation methods. The catalysts are very stable during the reaction. The presence of Bi as base center has promotion effect on the catalyst activity. The optimal Bi content is about 4% (molar fraction). With the increase of calcination temperature, the BET surface area of the catalysts is decreased and so is the activity of the catalysts. The activity of the catalysts and the Bi effect are discussed based on the reference results.

钯/铈复合金属氧化物催化氧化苯酚合成碳酸二苯酯

制备了一种用于非均相催化一步合成碳酸二苯酯(DPC)所需催化剂的载体(Ce_(1-x)Mn_xO_2),并采用沉淀法制备Pd负载质量分数为0.5%的Pd/Ce_(1-x)Mn_xO_2催化剂。采用X射线衍射(XRD)、扫描电镜(SEM)和比表面积测定(BET)等手段对载体及催化剂进行表征并考察载体制备方法、载体焙烧温度、Mn和CuO含量对催化剂活性的影响。结果表明,采用溶胶-凝胶法制备的载体Ce_(0.5)Mn_(0.5)O_2在600℃下焙烧6 h时,得到的催化剂催化活性较好,DPC收率可达9.32%。载体中添加CuO有助于提高催化剂活性,当CuO添加量质量分数为9.0%,活性组分Pd的负载量为0.5%,CO与O_2压力比为97:3时, DPC收率可达10.28%。