Ce_(0.8)Nd_(0.2)O_(1.9)-La_(0.95)Sr_(0.05)Ga_(0.9)Mg_(0.1)O_(3-δ)固体复合电解质的结构和电性能

采用溶胶-凝胶法分别制备La0.95Sr0.05Ga0.9Mg0.1O3-δ(LSGM)和Ce0.8Nd0.2O1.9(NDC)电解质,并在NDC溶胶中加入0-15%(w,质量分数)的LSGM预烧粉体制得NDC-LSGM复合电解质,研究不同质量比复合电解质的结构和电性能.采用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)和X能量色散谱仪(EDS)对样品进行结构表征,交流(AC)阻抗谱测试样品导电性能.结果表明:NDC-LSGM复合体系主要由立方萤石结构相、钙钛矿结构相和杂质相组成;LSGM的添加可促进晶粒的生长,产生大量相界面,清除或降低SiO2有害影响,明显提高晶界导电性;LSGM质量分数为10%的样品NL10具有最高晶界电导率和总电导率,400°C时NL10的晶界电导率σgb和总电导率σt分别为12.15×10-4和3.49×10-4S cm-1,与NDC的σgb(1.41×10-4S cm-1)和σt(1.20×10-4S cm-1)相比分别提高了7.62和1.91倍,总电导率的提高主要归因于晶界电导率的影响.     

La_(0.7)Pr_(0.15)Nd_(0.05)Mg_(0.3)Ni_(3.3-x)Co_(0.2)Al_(0.1)(Co_(0.75)Mn_(0.25))_x(x=0.0,0.2,0.4,0.6)的电化学性能研究

在Ar气保护下用悬浮熔炼制备La0.7Pr0.15Nd0.05Mg0.3N i3.3-xCo0.2A l0.1(Co0.75Mn0.25)x(x=0.0,0.2,0.4,0.6)合金,系统研究了Co和Mn对合金储氢性能和电化学性能的影响。XRD相分析表明,合金相主要由(La,Pr)(N i,Co)5,LaMg2N i9,(La,Nd)2N i7和LaN i3相组成;添加Co和Mn后合金中(La,Pr)(N i,Co)5,(La,Nd)2N i7和LaN i3相晶胞体积增加,LaMg2N i9相晶胞体积变小。合金放氢PCT曲线测试表明,随着合金中Co和Mn含量的增加,合金吸氢量先减小后增加,放氢平台压下降,合金氢化物稳定性增加。合金电极电化学性能测试表明,添加Co和Mn使合金电极放电容量减小,容量保持率S100从53.2%(x=0.0)增加到63.0%(x=0.6),合金电极的电循环稳定性增强,高倍率放电性能HRD1500先增加后减小。此外,合金电极的极化电阻先减小后增加,交换电流密度、循环伏安特性阳极峰电流密度和极限电流密度先增加后减小,合金内氢原子扩散系数先增加后减小,表明添加适量的Co和Mn可以提高合金电...     

Li_(3.22)Na_(0.569)Mn_(5.78)O_(12.0)的电化学性能

以L iOH.H2O和Mn(CH3COO)2.2H2O作原料,应用微波-固相两段烧结法合成具有L i4Mn5O12结构特征,组成为L i3.22Na0.569Mn5.78O12.0的锂离子电池正极材料.XRD分析表明,在380℃的后处理温度下,微波烧结前处理有利于生成纯L i4Mn5O12尖晶石相.充放电实验表明,在4.5~2.5V电压区间,新制样品的初始放电容量为132 mAh.g-1,100循环的容量衰减率为6.8%;4个月存放样的初始放电容量为122 mAh.g-1,100循环的容量衰减率为17.4%.表现出较好的充放电性能和循环寿命.微波烧结使样品的Mn-O键被加强.     

双水相萃取法分离铍(Ⅱ)、铁(Ⅲ)与铁(Ⅱ)、铬(Ⅲ)、锰(Ⅱ)、铝(Ⅲ)

研究了在聚乙二醇2000(PEG)-硫酸钠(Na2SO4)-邻苯二酚紫(PV)体系中铍(Ⅱ)、铁(Ⅲ)、铁(Ⅱ)、铝(Ⅲ)、铬(Ⅲ)、锰(Ⅱ)的萃取行为。试验结果表明,铍(Ⅱ)在pH 3.5-7.0及铁(Ⅲ)在pH 4.0-7.0范围内可以被PEG相几乎完全萃取,而铝(Ⅲ)、铬(Ⅲ)在pH 1.0-7.0、锰(Ⅱ)在pH 1.0-4.5、铁(Ⅱ)在pH 1.0-4.5则不被萃取。从而实现了将铍(Ⅱ)(pH 3.5)、铁(Ⅲ)(pH 5.0)与铝(Ⅲ)、铬(Ⅲ)、锰(Ⅱ)、铁(Ⅱ)混合离子的定量分离。同时探讨了PEG相的萃取机理。     

(S)-(-)-norlaudanosine和(S)-(-)-O,O-dimethylcoclaurine的合成

以高藜芦胺为起始原料,经N-磺酰化反应制得高藜芦磺酰胺(2);2分别与芳乙烯甲醚经对甲苯磺酸催化的Pictet-Spengler反应后用金属钠脱除Ts基团合成了(±)-norlaudanosine(5a)和(±)-O,O-dimethylcoclaurine(5b);使用半量拆分法,以N-乙酰-L-苯丙氨酸为拆分剂,制得(S)-(-)-5a和(S)-(-)-5b,其结构经1H NMR,13C NMR,IR,MS和HR-ESI-MS确证。     

质子导体BaCe_(0.8)Lu_(0.2)O_(3-α)的电性能(英文)

采用高温固相法制备了BaCe0.8Lu0.2O3-α质子导体。运用X射线衍射仪(XRD)、扫描电镜(SEM)对该材料的物相结构、微观形貌进行了表征。在500~900℃温度范围内,应用交流阻抗谱和气体浓差电池方法研究了材料在不同气体气氛中的离子导电性和氢-空气燃料电池性能。结果表明,BaCe0.8Lu0.2O3-α材料为单一斜方晶结构,具有良好的致密性。在500~900℃温度范围内,干燥或湿润的氮气、空气和氧气中,材料的电导率随着氧分压增大稍有增大。在湿润的氢气中,材料表现为纯的质子导电性。在以该材料为固体电解质的氢-空气燃料电池条件下,材料表现为质子、氧离子和电子的混合导电性,其中离子导电性始终占主导;氢-空气燃料电池在900℃下的最大输出功率密度为92.2mW·cm-2,高于我们以前报道的BaCe0.8RE0.2O3-α(RE=Pr,Eu,Ho,Er,等)材料。     

Ni_(x)Cu_(y)-B_(24)N_(28)催化CO_(2)氧化C_(3)H_(8)速控步骤的反应机理研究北大核心CSCD

采用密度泛函理论(DFT)研究了C_(3)H_(8)和CO_(2)在Ni_(x)Cu_(y)-B_(24)N_(28)(x+y=4,x=1、2、3、4)表面吸附及速控步骤反应机理.计算了C_(3)H_(8)、CO_(2)和相应中间体在Ni_(x)Cu_(y)-B_(24)N_(28)表面的吸附能以及6条可能路径下的反应热和活化能.计算结果表明,C_(3)H_(8)和CO_(2)在Ni_(x)Cu_(y)-B_(24)N_(28)表面是物理吸附,C_(3)H_(8)+CO_(2)→CH_(3)CHCH_(3)+OCOH是最有利的路径,其在不同催化剂表面的活化能顺序是NiCu_(3)-B_(24)N_(28)(1.42 eV)、Ni_(2)Cu_(2)-B_(24)N_(28)(1.57 eV)、Ni_(3)Cu-B_(24)N_(28)(1.62 eV)、Ni_(4)-B_(24)N_(28)(1.75 eV).由此可知,在Ni_(x)Cu_(y)-B_(24)N_(28)催化CO_(2)氧化C_(3)H_(8)的体系中,Cu含量直接影响其催化活性,即NiCu_(3)-B_(24)N_(28)用于催化CO_(2)氧化C_(3)H_(8)有一定优势.     

Au-MmNi_(3.2)Al_(0.2)Mn_(0.6)Co_(1.00)电极对NaBH_4电催化氧化

研究经NaOH处理了的MmNi3.2Al0.2Mn0.6Co1.0,再应用电沉积法制备Au改性的MmNi3.2Al0.2Mn0.6Co1.0催化剂对NaBH4的电催化氧化性能.SEM观察催化剂样品的微观形貌,线性伏安扫描法测定其电催化氧化性能,发现Au-MmNi3.2Al0.2Mn0.6Co1.0电极电催化氧化NaBH4电流密度为60 mA.cm-2,比在MmNi3.2Al0.2Mn0.6Co1.0电极的增加3.5倍.若对该电极在电解质中预浸泡10 h,则氧化电流密度可达到184 mA.cm-2.     

Synthesis and Crystal Structure of Trans-diaquabis(hexamethylenetetramine-N)bis(isothiocyanato)cobalt(Ⅱ) trans-tetraaquabis(isothiocyanato)cobalt(Ⅱ) dihydrate

1 INTRODUCTION Supramolecular compounds assembled by coordination covalent bonding or hydrogen bonding are of considerable interest due to their potential applications in developing new materials with magnetic, optical and catalytic properties[1]. One of the synthesis methods used to construct the functional compounds is that octahedral metal ion connects to polydentate ligand such as 4, 4?bipyridine, pyrazine and so on to form multi-dimensional supramolecular polymer[2]. Hmt (hexamethyl…     

(Ce_(0.67)Tb_(0.33))MgAl_(11)O_(19)和BaMgAl_(10)O_(17)∶Eu~(2 )荧光体的微波辐射合成及其发光性能

用微波辐射法合成了（Ｃｅ０．６７Ｔｂ０．３３）ＭｇＡｌ１１Ｏ１９（ＰＧ）和ＢａＭｇＡｌ１０Ｏ１７（ＰＢ）两种荧光体，经Ｘ射线粉末衍射分析，其ｄ值和Ｉ／Ｉ０值与ＪＣＰＤＦ３６７３和２６１６３基本一致。计算得到ＰＧ的晶胞参数ａ＝０５５８２ｎｍ，ｃ＝２１８８４ｎｍ；Ｐ－Ｂ的晶胞参数α＝０５６１６ｎｍ，ｃ＝２２６１４ｎｍ。测定了两种荧光体的激发光谱和发射光谱。Ｐ－Ｇ的色坐标ｘ＝０３１６，ｙ＝０５６５；Ｐ－Ｂ的色坐标ｘ＝０１５６，ｙ＝０１０６。与市售同类荧光粉相比，Ｐ－Ｇ的相对发光强度为８８％，Ｐ－Ｂ的相对发光强度为８０％。     

Novel Ba_(0.5)Sr_(0.5)Fe_(0.8)Zn_(0.2)O_(3-δ) membranes for POM

A novel cobalt-free perovskite based on Ba_(0.5)Sr_(0.5)Fe_(0.8)Zn_(0.2)O_(3-δ)(BSFZ)were prepared by EDTA-citric acid method.The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction(HTXRD).The thermal expansion coefficient of BSFZ is 10.5×10~(-6)K~(-1),which is lower than that of cobalt-based perovskite materials.The BSFZ membrane was also used to construct reactors for the partial oxidation of methane(POM)to syngas.Results show that the BSFZ membrane...     

贮氢电极合金ZrCr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2)高温电化学性能的研究

研究了AB2型Laves相贮氢电极合金ZrCr0.4Mn0.2V0.1Co0.1Ni1.2在不同温度下的放电容量、活化、高倍率和自放电等电化学性能.实验表明:25℃下,合金电极经13次循环后其最大放电容量为336mAh/g,在70℃下,仅需4次循环就达到298mAh/g;该合金在70℃,300mA/g电流下的高倍率放电性能比25℃时提高了约16%,但自放电性能却从3%/d下降到17%/d,虽然温度升高,合金的循环性能有所下降,但还是相当稳定的.这主要是因为循环过程中合金表面形成的氧化膜阻碍了合金元素进一步溶解造成的.     

X-ray structures of trans-dichloro(4-methylpyrimidine) (η1-phenyl)bis(pyridine)rhodium(III) hydrate and trans-dichloro(phenyl)tris(triphenylstibine)rhodium(III) ethylacetate solvate. Molecular orbital analysis of trans-dichloro (4-methylpyrimidine)(η1-phenyl)bis(pyridine)rhodium(III)

The crystal and molecular structure of trans-dichloro(4-methylpyrimidine)(η ¹ -phenyl)cis-bis(pyridine)rhodium(III) water solvate, 1x 0.17H₂ O, and trans-dichloro(η ¹ -phenyl)tris(triphenylstibine)rhodium(III) ethylacetate solvate, 2x CH₃ CO₂ CH₂ CH₃ have been studied via X-ray diffraction from a single crystal at room temperature. The final refinement converged to R1 conventional index of 0.0350 and 0.0361 for the structural analysis of 1x 0.17H₂ O [space group R(-3) and 2x CH₃ CO₂ CH₂ CH₃ P(-1) , respectively. The 4-methylpyrimidine ligand (Pym) is only weakly bound to Rh in 1, as shown by the long Rh-N distance (2.251(4) Å), compared to the Rh N(pyridine) lengths average, 2.066(4) . N-C bond distances involving the N donor average 1.329(6) and 1.345(6) for Pym and pyridine (Py) ligands, respectively. The C N C bond angle on the donor is 114.1(5)° for Pym and average 117.4(4)^° for Py.The structure of the complex molecule of 2x CH₃ CO₂ CH₂ CH₃ has some differences when compared to that of the corresponding acetone solvate previously studied in this laboratory (Cini, R., Giorgi, G. and Pasquini, L., Inor`. Chim. Acta, 1992, 196, 7). The two structures differ mainly by the orientation of the phenyl donor with respect to the Cl-Rh-Cl axis (which is more eclipsed for the ethylacetate solvate) and by the conformation of the SbPh₃ ligands.Density functional calculations at the B3LYP/LANL2DZ level with full geometry optimization were carried out on the free Pym molecule and on some Sc(N ¹ Pym) ^{3 +}and Sc(N ² Pym) ^{3 +} model molecules. The effect of metal coordination consists mainly in enlarging the (Sc)N-C bond distances up to 0.150Å, whereas the C-N(Sc)-C bond angle decreases of 1.9°. Significant changes on other bond lengths and angles relevant to ring atoms of Pym occur upon metal coordination to the nitrogen atom. The metal coordination to N(2) is less favorable than to N(1) of 7.5 kcal for 1:1 species of Sc^{3 +}Extended Hückel calculations showed that HOMO consists mostly of metal-d orbitals with some character of chloride and phenyl and pyrimidine ligands, whereas LUMO is composed of phenyl, pyridine and pyrimidine orbitals. The method well reproduces the Rh-N and Rh-C bonding distances and gives Rh-C dissociation energy 2.38 and 5.48 times that for the Rh-N(Py) and Rh-N(Pym) bonds, respectively.     

Nd_2(Fe_(1-x)Co_x)_(14)B和Y_2(Fe_(1-x)Co_x)_(14)B的磁性

用磁测量和X-射线衍射研究了Nd_2(Fe_(1-x)Cox)_(14)B和Y_2(Fe_(1-x)Cox)_(14)B的晶格结构和内禀磁性。结果表明,低温下当钴含量较少时,Y_2(Fe_(1x)Cox)_(14)B的磁晶格向异性随钴含量的增加而增加,在1.5K和150K温度下,分别在x为0.4和0.2左右时磁晶各向异性常数达到极大;室温时的磁晶各向异性常数却随钴含量的增加而单调下降。用钴代换铁,对Nd_2(Fe_(1-x)Cox)_(14)B的自旋再取向温度的影响是复杂的。1.5K的饱和磁化强度在x=0.1左右达到极大。钴可以显著提高居里温度,对于Nd_2(Fe_(1-x)Cox)_(14)B和Y_2(Fe_(1-x)Cox)_(14)B,钴的作用几乎相同,表明居里温度主要由3d过渡金属原子之间的交换作用决定。     

New access to (η(5)-cyclohexadienyl)Mn(CO)3 and cationic (η(6)-arene)Mn(CO)3 complexes by Suzuki-Miyaura reaction

First Suzuki-Miyaura coupling reactions applied to (η(5)-chloro-cyclohexadienyl)Mn(CO)3 complexes are described and lead to the syntheses of (η(5)-aryl-cyclohexadienyl)Mn(CO)3 and of cationic (η(6)-arene)Mn(CO)3 complexes after rearomatization. The structures of two of the new complexes have been investigated by X-ray diffraction study.     

~(13)C核磁共振(六)

分子式为C_6H_8O的哪一个化合物与图E-11符合? 取谱条件: 溶剂:CDCl_3(δ77.2三重峰) 浓度:50V/V％温度:28℃测定频率:22.63MHz 去偶:上——~1H偏共振去偶(500次) 下——~1H宽带去偶(100次) [解答]C_6H_8O含有三个双键当量。在~(13)C谱中找到一个羰基(δ198.65)以及一个C=C键(δ150.6及129.85)。还余下一个双键与三个次甲基(δ38.2,25.75及22.95)。总结起     

~(13)C核磁共振(五)

习题1 分子式为C_4H_(10)S的哪一个化合物符合图E-1的~(13)C谱?对此谱作出归属。取谱条件: 溶剂:CDCl_3(δ77.25处有三重峰,图中未画出) 浓度:50V/V％温度:28℃测定频率:22.63MHz 去偶:上——~1H偏共振去偶(200次) 下——~1H宽带去偶(100次)     

~(13)C核磁共振(七)

习题16 1,3,5-三硝基苯与丙酮在氢氧化钾的乙醇溶液存在下反应生成一种蓝紫色的Meisenheimer钾盐,见谱E-16。分析此谱并给出从谱所得最重要的论点以支持此盐的结构。取谱条件: 溶剂,(eD,),50(3,.7七重峰,Je-一20.5Hz) 浓度:饱和溶液温度:28℃测定频率:22.63 MHz 去偶.上.偶合谱(25000次),附有放大四倍的部分谱下:几H宽带去偶( 5000次)〔解答〕谱的归属     

~(13)C核磁共振(四)

9 ~(13)C自旋-晶格弛豫时间(T_1)的测量及应用 9.1 测定T_1的方法 9.1.1 倒向—恢复法此法是用(180°-τ-90°)_n脉冲系列作用于样品。磁化矢量M_0在180°脉冲作用下倒向(图20b),在自旋-晶格弛豫过程中,磁化矢量从-M_0经0到 M_0弛豫,在这一过程中,即过了时间τ后,90°脉冲将部份弛豫的磁化矢量M_τ旋转到X(?)Y平面中,并在接收线圈中感应出FID信号。如果τ很短,M_τ还是负的(M_τ<0),90°脉冲(?)_1,作用后M_τ沿X向负Y轴旋转(图20c),     

~(13)C核磁共振(三)

8.1 通过一个键的C与H偶合除了化学位移之外,C—H的偶合常数也能提供重要的信息,测量J值时必须取不去偶或用交替脉冲双共振方法。这两种方法都需时较长,并且要求样品量较多。~1J_(CH)也可从~1H谱的~(13)C卫星线测得。 ~1J_(CH)在120-130Hz之间~2J(CH)、~3J(CH)~4J(CH)都小于