类溶胶-凝胶法制备LiMn_2O_(4-δ)Cl_δ正极材料

本文以水合氢氧化锂 (LiOH .H2 O)、水合硝酸锰 (Mn(No3) 2 .6H2 O) ,水合氯化锂 (LiCl.H2 O)为原料 ,用类溶胶 凝胶法制备了LiMn2 O4 δClδ,并且以此作正极进行了电化学测试 .结果表明 ,掺氯的尖晶石LiMn2 O4 正极材料具有优异的稳定性 ,且循环稳定后 ,容量几乎没有衰减 .     

Preparation and Characterization of Single-Phase Perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ

Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ has been successfully prepared by using citrate-EDTA complexation method at relatively low calcination temperature. The structure and thermal decomposition process of the complex precursor have been investigated by means of differential scanning calorimetry-thermal gravimetric analysis (DSC/TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopic (FT-IR) measurements. The precursor decomposed completely and started to form perovskite-type oxide above 420℃ according to the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results. Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ obtained has been confirmed from the XRD pattern, and no peak of SrCO3 was found by XR.D of the oxides synthesized at a relatively low temperature of 800 ℃. The reducibility of La0.6Sr0.4Co0.8Fe0.2O3-δ was also characterized by the temperature programmed reduction (TPR) technique. Disk shaped dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was prepared by the isostatical pressing method. The oxygen flux rate of dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was (2.8-18)×10-8 mol/(cm2·s) in the temperature range of 800-1 000℃.     

YBa2CU3O7-δ掺杂PbO和BaPbO3的性质研究

测量了不同含量PbO和BaPbO3掺杂YBa2Cu3O7-δ的熔化温度和超导临界转变温度(T.).在YBa2Cu3O7-δ中掺入PdO可以降低熔点,但X射线衍射分析表明高温下YBa2Cu3O7-δ与PdO发生了反应生成BaPbO3,降低了样品的超导电性.分别用BaCO3与PdO,BaCO3与PdO2合成了单相的BaPdO3.在YBa2Cu3O7～δ中添加了不同含量的BaPdO3(10%,20%,30%).X射线衍射分析表明YBa2Cu3O7-δ与BaPbO3没有发生反应.掺杂了BaPbO3的YBa2Cu3O7-δ比掺杂PdO具有较好的超导电性,但是不能降低YBa2Cu3O7-δ的熔点.     

Electrochemical Properties of Spinel LiMn2O4-d Fd for Cathode Materials of Secondary Lithium-ion Battery

The spinel LiMn2O4-δ Fδ cathode materials were synthesized by solid-state reaction, with calculated amounts of LiOH·H2O, MnO2(EMD), LiF. The results of electrochemical test demonstrated that these new materials exhibited excellent electrochemical properties. Its initial capacity reached ～115 mAh·g-1 and reversible efficiency is about 100%. After 60 cycles, its capacity was still around 110 mAh·g-1, with nearly 100% reversible efficiency.     

δ~(18)O CONTOURS AND ANCIENT FOSSIL HYDRO-THERMAL SYSTEM OF MIAROLITIC ALKA-LINE GRANITE,NIANZISHAN,HEILONGJIANG

The H and O isotope compositions of 41 whole rocks and 24 separated minerals of theNianzishan miarolitic alkaline granite and 3 local meteoric water samples have been meas-ured. The results indicate that the meteoric-hydrothermal convective system might have beendeveloped in this stock. The distributions of δ~(18)O values of whole-rock samples formed anapproximateIy δ~(18)O contours with the characteristic of kighest values in the midst and de-creasing toward the outer zones. The water/rock ratio (W/R) contours were also calculated.This phenomenon might have common significance for stocks or plutons.     

Fe(OH)2悬浮液在EDTA作用下氧气氧化生成δ-FeOOH的机理研究

At room temperature and in the presence of trace EDTA, the formation of δ-FeOOH was studied by the rapid oxidation of Fe(OH)2 suspension with O2. The structural and morphological changes were characterized by various techniques such as XRD, FTIR and TEM. γ-FeOOH and δ-FeOOH formed simutaneously in the early period of oxidation. But as the rate of mass transfer was in equilibrium, trace γ-FeOOH vanished gradually. Accordingly, pure phase δ-FeOOH was obtained. At the same time, critical amount ratio K of EDTA to Fe^2 was verified. The experiments show that the reactivity, rate of the oxidizing agent and pH of the initial medium were important factors for the formation of pure phase δ-FeOOH. Under the auxiliary effect of EDTA, the reactivity of O2 was nearly improved to that of H2O2. And the process of the oxidation that Fe(OH)2 suspension was oxidized by O2 under that condition was discussed.     

Partial Oxidation of Methane to Synthesis Gas over Hexaaluminates LaMAl_(11)O_(19-δ) catalysts

A series of M-substituted hexaaluminates LaMAl11O19-δ(M=Fe, Co, Ni, Mn, and Cu) were prepared and characterized by XRD, XPS, TPR and TGA techniques, respectively. They exhibited different reducibility and catalytic activity for partial oxidation of methane (POM) to synthesis gas. Among the LaMAl11O19-δsamples, LaNiAl11O19-δshowed the best catalytic activity for the topic reaction and selectivity for synthesis gas at 780℃for 2 h. The conversion of CH4 was over 99.2%, and the product selectivity for both CO and H2 was above 90.3%.     

多层膜结构BaCe0.9Nd0.1O3-δ的制备及其在常压合成氨中的应用

用干压法制备了Ni-BaCe0.9Nd01O3-δ多孔金属陶瓷阳极,并在阳极基膜上制备出致密的BaCe0.9Nd0.1O3-δ固体电解质薄膜.薄膜的厚度约为40 μm,致密均匀.测定了多层膜结构BaCe0.9Nd0.1O3-δ在干燥氮气/湿润氢气气氛中的电导率,结果表明其电导率要比厚膜BaCe0.9Nd0.1O3-δ和SrCe0.95Y0.05O3-δ(SCY)要高.将多层膜材料用于固态质子传导电池中,在常压下以氮气和氢气为原料合成了氨气.结果表明,与SCY固体电解质比较,氨的产率提高了一个数量级以上.     

Thermal transformation of δ-MnO2 nanoflowers studied by in-situ TEM

In-situ transmission electron microscopy in combination with a heating stage has been employed to real-time monitor variations of -phase MnO2 nanoflowers in terms of their morphology and crystalline structures upon thermal annealing at elevated temperatures up to ~665℃. High-temperature annealing drives the diffusion of the small δ-MnO2 nanocrystallites within short distances less than 15 nm and the fusion of the adjacent δ-MnO2 nanocrystallites, leading to the formation of larger crystalline domains including highly crystalline nanorods. The annealed nanoflowers remain their overall flower-like morphology while they are converted to δ-MnO2 . The preferred transformation of the δ-MnO2 to the δ-MnO2 can be ascribed to the close lattice spacing of most crystalline lattices between δ-MnO2 and δ-MnO2 , that might lead to a possible epitaxial growth of δ-MnO2 lattices on the δ-MnO2 lattices during the thermal annealing process.     

Co掺杂的YBa2Cu2O6+δ的氧非计量和氧渗透性能研究

研究钴离子部分取代铜离子对YBa2Cu3O6+δ的氧非计量值δ和氧渗透率的影响.对于钴替代的样品,氧非计量的绝对值变大,且其数值不再随温度和氧分压的变化发生显著变化.YBa2Cu2CoO6+δ样品在中、高温具有可观的氧渗透率.对于厚度为1.2 mm的致密YBa2Cu2CoO6+δ样品,在850℃时,只要在样品两端施加较小的氧分压差(PO2=21.2 kPa、 PO2=101 Pa),其氧渗透率即可达57 μmol/cm2 s, 明显高于YBa2Cu3O6+δ的氧渗透率(31 μmol/cm2 s).YBa2Cu2CoO6+δ的高氧渗透率在结构上可被归结为位于晶胞基面上的氧离子和氧空位的均匀分布.     

The Effect of Rare Earth on the Activity of Methanol Synthesis Catalyst

AlthoughtheCuO/ZnO/Al=O,cataIysthasbeenusedasasuccessfulmethan0lsynthesiscatalystfromCOhydrogenationformanyyears,itscatalyticactivityisnothighenoughf0rmethan0Isynthesisfr0mpureCO,hydrogenati0n.Manynewsynthesismethods,includingsol-gelco-precipitati0nmethodandultrasonicsynthesismeth0d,wereusedtopreparethemethanolsynthesiscatalyst"'.Intheliterature,manymetal0xidessuchasZrO,,Cr,O,,Ga,O,,Al,O,,SiO,andTiO,etc.wereaddedintocatalystt0improveitscatalyticactivityandmethanoIselectivity'~'.Howev…     

Ce1 - x Tbx O2 - δ复合氧化物氧缺位的拉曼光谱研究

采用溶胶-凝胶法制备了Ce1-xTbxO2-δ复合氧化物,利用不同Raman激发波长(514和785 nm),结合X射线衍射(XRD)、氢气-程序升温还原(H2-TPR)和氧气-程序升温脱附(O2-TPD)表征,考察了Ce1-xTbxO2-δ复合氧化物在O2,He和H2气氛下氧缺位的原位变化情况和CeO2的F2g特征Raman峰位的偏移. 实验结果表明,随着Tb掺杂量的提高,由于晶胞收缩使得CeO2的F2g特征Raman振动峰发生蓝移. 514 nm Raman激发波长反映了催化剂的表面信息,而785 nm激发波长反映了整体信息. 正是由于表面和整体变化的不一致,造成原位Raman实验过程中氧缺位浓度变化趋势的不同. 在He和H2气氛下,由于温度升高时伴随着Ce1-xTbxO2-δ中O2气的脱出,使复合氧化物的微观结构发生改变,以致Ce0.9Tb0.1O2-δ中的氧缺位浓度(A587/A465)在785 nm激发波长下出现先升高后下降的现象.     

La_(1-x)Ca_xMnO_(3+δ)钙钛矿催化剂制备及其甲烷催化燃烧性能研究

采用柠檬酸配合法制备了系列La1-xCaxMn O3+δ(x=0,0.03,0.05,0.07,0.1,0.15,0.2)催化剂,采用低温N2物理吸附,氢程序升温还原(H2-TPR)、氧程序升温脱附(O2-TPD),X-射线衍射(XRD)和X-射线光电子能谱(XPS)研究了其物理化学性质,并考察了甲烷催化燃烧活性.结果表明,当Ca摩尔掺杂量为0.1时,催化活性最好.XRD和BET表征结果表明Ca可以进入钙钛矿结构中,Ca掺杂对催化剂的比表面积无显著影响.H2-TPR和XPS表征结果表明Ca掺杂增加了Mn4+的含量.O2-TPD表征结果表明适量Ca掺杂可以降低晶格氧脱出温度.Mn4+具有较强氧化性,因此提高了催化活性,但随着Ca掺杂量增加,催化剂表面吸附氧含量有所减少,表明气相中氧难以迅速补充消耗的晶格氧,Ca掺杂量继续增加又会使催化活性有所下降.依据反应机理,Ca掺杂一方面可以促进Mn4+含量增加,有利于催化活性;另一方面会使催化剂表面吸附氧含量有所下降,降低了催化活性.     

中温固体氧化物燃料电池LaNi_(0.6)Fe_(0.4)O_(3-δ-)Gd_(0.2)Ce_(0.8)O_2梯度复合阴极制备及交流阻抗性能

应用丝网印刷和共烧结制备LaNi0.6Fe0.4O3-δ(LNF)-Gd0.2Ce0.8O2(GDC)梯度复合阴极/Gd0.2Ce0.8O2/Sc0.1Zr0.9O1.95(ScSZ)/Gd0.2Ce0.8O2/LaNi0.6Fe0.4O3-δ(LNF)-Gd0.2Ce0.8O2(GDC),组成梯度复合阴极对称电池.实验表明,在750 oC工作温度下单层70%LNF-30%GDC(文中均指质量百分比)复合阴极的极化电阻为0.581Ω·cm2,而三层60%LNF-40%GDC/70%LNF-30%GDC/100%LNF复合阴极的极化电阻最小(0.452Ω·cm2).由于阴极组成在ScSZ电解质和LNF阴极之间呈梯度变化,因此获得了最佳的阴极/电解质界面,大大加快了三相界面或气体/阴极/电解质三相接触点反应区的扩散,其电荷传递电阻Rct和浓差极化电阻Rd均减小,因而具有最低的阴极极化电阻值.     

Raman Scattering of Nanocrystalline δ-TiNx Synthesized by Mechanical Milling

Introduction Raman scattering is a powerful nondestructive technique that gives vibrational information about organic and inorganic materials. Raman scattering features, such as intensity, frequency and width, are strongly dependent on compositions, defects, short-range orders, crystal structures, and internal stresses of materials. Therefore, it has been widely used to obtain detailed information about the structural properties of semiconductors, high-Tc superconductors, ceramics, catalysts, carbon based materials, and Ⅲ-Ⅴ valent metallic nitride materials, including lattice perfection, strain, crystalline, interface, and compositional uniformity[1].     

Gd0.2Ce0.8O2包覆LaNi0.6Fe0.4O3-δ阴极制备及性能

应用丝网印刷和共烧结制备LaNi0.6Fe0.4O3-δ/Sc0.1Zr0.9O1.95/LaNi0.6Fe0.4O3-δ对称电池.以硝酸铈和硝酸钆为原料,柠檬酸作燃料,燃烧合成Gd0.2Ce0.8O2(GDC)包覆的LaNi0.6Fe0.4O3-δ(LNF)阴极.实验表明,在750oC工作温度下,纯LaNi0.6Fe0.4O3-δ阴极的极化电阻为0.70Ω.cm2,而21.3%(by mass,下同,如无特殊标注均为质量分数)GDC包覆的LNF-GDC复合阴极的极化电阻最小(0.13Ω.cm2),活化能最低(136.80 kJ.mol-1),故其阴极性能最佳.GDC的包覆加速了气体/阴极/电解质三相界面反应区的扩散过程,降低了阴极极化电阻.     

Synthesis and characterization of gallium-based perovskitetype dense membrane with oxygen semipermeability

La0.15Sr0.85Ga0.3Fe0.7O3-δ(LSGFO) and La0.15Sr0.85Co0.3Fe0.7O3-δ(LSCFO) mixed oxygen-ion and electron conducting oxides were synthesized by using a combined EDTA and citrate complexing method, and the corresponding dense membranes were fabricated. The properties of the oxide powders and membranes were characterized with combined SEM, XRD, H2-TPR, O2-TPD techniques, mechanical strength and oxygen permeation measurement. The results showed that LSGFO had much higher thermochemical stability than LSCFO due to the higher valence stability of Ga3+. After the temperature-programmed reduction by 5% H2 in Ar from 20℃to 1020℃, the basic perovskite structure of LSGFO was successfully preserved. LSGFO also favors the oxygen vacancy formation better than LSCFO. Oxygen permeation measurement demonstrated that LSGFO had higher oxygen permeation flux than LSCFO, but they had similar activation energy for oxygen transportation, with a value of 110 and 117 kJ ?mol~(-1), respectively. The difference in oxygen permeation f     

Pd/Ce0.8Zr0.15La0.05Oδ整体催化剂甲苯催化燃烧性能的研究

采用一次浸渍法分别制备了 Pd/Ce0.8Zr0.15La0.05Oδ及Pd/Ce0.8Zr0.2O2整体式蜂窝陶瓷催化剂,考察了不同温度焙烧的两类整体催化剂甲苯催化燃烧性能.通过X射线粉末衍射(XRD)、比表面积、拉曼光谱(Raman)、程序升温还原(H2-TPR)、PdO分散度等表征结果与催化活性进行关联.结果表明,随着焙烧温度升高,催化剂比表面积下降,Raman图谱CeO2及PdO峰强度增加,H2-TPR中Ce4+还原峰向高温方向移动,同时PdO分散度下降,相应甲苯催化氧化活性下降.与CeO0.8Zr0.2O2涂层催化剂相比,La3+掺杂催化剂在高温焙烧时,其比表面积下降较小,Raman光谱表明其氧缺位比铈锆涂层催化剂多,H2TPR谱图中Ce4+还原峰低约60～80℃,PdO分散度亦比末掺杂催化剂高.1000℃焙烧下的甲苯氧化反应活性远高于未掺杂催化剂,说明镧的掺杂提高了铈锆涂层催化剂的高温反应活性及热稳定性.     

Influence of Addition of ZnO on Property of Fe2O3-K2O System Catalyst for Ethylbenzene Dehydrogenation to Styrene

The incorporation of ZnO into Fe2O3-K2O system increases its activity, enhances its moisture stability and mechanical strength. The origin of the enhancement in activity and moisture stability is discussed in the light of experimental results obtained by BET, XRD, XPS. It was found that the addition of ZnO to Fe2O3-K2O system strengthens the interaction between Fe2O3 and K2O, reduces the formation temperature of KFe11O17 at least by 50℃, and promotes the transformation of Fe^3 to Fe^2 further.     

CO2重整甲烷制合成气催化剂六铝酸盐LaNiy/Al12-yO19-δ的研究

A series of Ni modified hexaaluminates LaNi y Al 12- y O 19- δ ( y =0 3, 0 6, 0 9, 1 0) were prepared by decomposition of nitrates and calcination at high temperature. The crystalline structure and catalytic properties for CO 2 reforming of methane to synthesis gas were investigated by using XRD, XPS, TPR and TGA techniques. The results showed that a pure hexaaluminate LaNi y Al 12- y O 19- δ phase is formed only when y value is in 0< y ≤1. The reduced hexaaluminates LaNi y Al 12- y O 19- δ exhibit significant catalytic activity and stability for the reaction of CO 2 reforming of methane to synthesis gas at 780 ℃, and no deactivation resulting from carbon deposition is found. In the meantime, the catalytic activity is obviously affected by the modifier Ni in the hexaaluminate lattices. Under the same reaction conditions, the conversion of CH 4 and CO 2 increase with increase in the amount ( y value) of the modifier Ni.