SrFeCo0.5O3.25+δ粉体的合成和透氧膜的制备及其性能研究

采用甘氨酸－硝酸盐法合成Ｓｒ－Ｃｏ－Ｆｅ复合氧化物超细粉体,用以制备组成为ＳｒＦｅＣｏ０．５Ｏ３。２５＋δ（ＳＦＣ）致密透氧陶瓷膜,结果表明粉体分散性和烧结性能好,残碳量可忽略,组成符合给定的化学计量比。对ＳｒＦｅＣ０．５Ｏ３．２５＋δ陶瓷膜材料进行了相结构、微结构、电导和氧渗透性能的研究,所获得的ＳＦＣ透氧膜材料有较高的氧渗透率,并与传统的固相反应法制得的样品进行了比较。     

(Ba,Ca)(Co,Fe)O3-δ系列混合导电型透氧膜的研究

采用改进的Ｐｅｃｈｉｎｉ法合成了（Ｂａ,Ｃａ）（Ｃｏ,Ｆｅ）Ｏ３－δ系列材料,对其结构,透氧量及透氧稳定性进行了考察,结果表明,材料具有较高的透氧量和透氧稳定性,其中Ｂａ０．９５Ｃａ０．０５Ｄｏ０．８Ｆｅ０．２Ｏ３－δ在９５０℃透氧量高达１．４ｍｌ／（ｃｍ＾２．ｍｉｎ）,８５０℃稳定操作１６０ｈ以上,将其应用于膜反应器,对无催化剂的甲烷氧化偶联反应作了尝试,结果表明,对甲烷氧化偶联反应具有较高的选择,但甲烷转化率较低。     

膜反应器中的甲烷转化反应

用ＥＤＴＡ－柠檬酸联合络合法合成了Ｂａ０．５Ｓｒ０．５Ｃｏ０．８Ｆｅ０．２Ｏ３－δ混合导体透氧膜材料,并考察了膜片本身对甲烷的活化性能,结果表明,导体膜对甲烷氧化偶联（ＯＣＭ）反应具有催化活性,研究了膜反应器中甲烷部分氧化（ＰＯＭ）制合成气反应,发现在开始阶段甲烷转化率有两次快速升高,第一次是由于甲烷与二氧化碳重整而产生的;第二次是由于透氧量增加而导致的,透氧量随温度的升高而增加,８５０℃时甲烷转     

等瓣置换反应的研究──手性簇合物［（η~5－MeO_2CC_5H_4）（CO）_2Mo］·［（η~5－MeO_2CC_5H_4）（CO）_2W］Fe（CO）_3（μ_3－S）的分子结构及晶体结构

用Ｘ射线衍射法测定了由η~５－ＭｅＯ_２ＣＣ_５Ｈ_４）（ＣＯ）_３ＭｏＮａ和［（η~５－ＭｅＯ_２ＣＣ_５Ｈ_４）（ＣＯ）_２Ｗ］Ｆｅ－（ＣＯ）_３Ｃｏ（Ｃｏ）_３（μ_３－Ｓ）的等瓣置换反应所生成的手性簇合物──［（η~５－ＭｅＯ_２ＣＣ_５Ｈ_４）（ＣＯ）_２Ｍｏ］－［（η~５－ＭｅＯ_２ＣＣ_５Ｈ_４）（ＣＯ）_２Ｗ］Ｆｅ（ＣＯ）_３（μ_３－Ｓ）的分子结构及晶体结构。晶体属Ｐ１空间群，晶胞参数α＝０．８７１６２（５）ｎｍ，ｂ＝０．７６２１８（４）ｎｍ，ｃ＝１．８７１１１（８）ｎｍ；α＝９４．１６４（４）°，β＝９７．９７９（２）°，γ＝９９．１０８（２）°，Ｚ＝２，μ＝５．９ｃｍ~（－１）。最终的一致性因子Ｒ＝０．０３６，Ｒｗ＝０．０３７．该簇合物含ＭｏＷＦｅＳ四面体簇核，其中Ｍｏ、Ｗ原子以１：１的比例无序地分占了四面体的２个顶点．     

Syntheses and Characterizations of （η~5－C_5H_5）MoFeCo（CO）_8（μ_3－S） and （η~5－C_5H_5）_2Mo_2Fe（CO）_7（μ_3－S）：X－ray Crystal Structure of （η~5－C_5H_5）MoFeCo（CO）_8（μ_3－S）

ＳｙｎｔｈｅｓｅｓａｎｄＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｓｏｆ（η~５－Ｃ_５Ｈ_５）ＭｏＦｅＣｏ（ＣＯ）_８（μ_３－Ｓ）ａｎｄ（η~５－Ｃ_５Ｈ_５）_２Ｍｏ_２Ｆｅ（ＣＯ）_７（μ_３－Ｓ）：Ｘ－ｒａｙＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ（η~５－Ｃ_５Ｈ_...     

含MoFe3Se4类立方烷核芯簇合物的合成与结构表征

室温下［Ｅｔ_４Ｎ］_２ＭｏＳｅ_４, ＦｅＣｌ_２和 Ｒ_２ＮＣＳ_２Ｎａ在 ＤＭＦ和 ＣＨ_３ＣＮ混合溶剂中反应,得到含ＭｏＦｅ_３Ｓｅ_４核芯的Ｍｏ－Ｆｅ－Ｓｅ簇合物ＭｏＦｅ_３Ｓｅ_４（μ－Ｒ_２ＮＣＳ_２）_２（Ｒ_２ＮＣＳ_２）_４（Ｒ２＝Ｍｅ_２（１）,Ｅｔ_２（２）,Ｃ_４Ｈ_８（３））．化合物２的单晶Ｘ射线衍射分析表明,其分子结构为２个桥式和４个螫合Ｅｔ_２ＮＣＳ_２~－配体包围的一个扭曲类立方烷Ｍ_４Ｓｅ_４簇核对３个化合物的ＣＶ进行了表征,它们在ＤＭＳＯ溶液中的电化学行为表现出了多电子可逆的传递过程．     

（四甲基二硅撑）双（3－三甲硅基环戊二烯基）－四羰基二铁的反应性

标题化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２／（μ－ＣＯ）_２（Ａ）分子中的Ｆｅ－Ｆｅ键被钠汞齐还原断裂，生成相应的双铁负离子，分别与ＭｅＣＯＣｌ、ＰｈＣＯＣｌ、ＰｈＣＨ_２Ｃｌ、ＣｌＣＨ_２ＣＯＯＣ_２Ｈ_５和Ｐｈ_３ＳｎＣｌ进行亲核取代反应，生成在铁原子上引入相应取代基的产物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２Ｒ］_２（Ｒ：ＭｅＣＯ（１），ＰｈＣＯ（２），ＰｈＣＨ_２（３），ＣＨ_２ＣＯＯＣ_２Ｈ_５（４），Ｐｈ_３Ｓｎ（５），Ｉ（６））。Ａ在氯仿中与碘反应，得到Ｆｅ－Ｆｅ断裂的双铁碘化物，但在苯中与过量碘反应，则得到Ｆｅ－Ｉ－Ｆｅ桥联的离子型化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２Ｉ·Ｉ（７）。化合物６的晶体和分子结构经Ｘ射线衍射测定，６属单斜晶系，Ｐ２１／ｃ空间群，ａ＝１．７２１７（４）ｎｍ，ｂ＝０．７７５３（２）ｎｍ，Ｃ＝１．３６２９（７）ｎｍ，β＝１０３．８０（３）°，Ｖ＝１．７６７（２）ｎｍ３，Ｚ＝４，Ｄｃ＝１．６２９９·ｃｍ－１，最终偏差因子Ｒ＝０．０５４。     

等瓣置换反应的研究——手性簇合物[η^—MeO2CC5H4）（CO）2Mo…

用Ｘ射线衍微法测定了由η＾５－ＭｅＯ２ＣＣ５Ｈ４（ＣＯ）３ＭｏＮａ和〔（η＾５－ＭｅＯ２ＣＣ５Ｈ４）（ＣＯ）２Ｗ〕Ｆｅ－（ＣＯ）３Ｃｏ（ＣＯ）３（μ３－Ｓ）的等瓣置换反应所生成的手性簇合物－〔（η＾５－ＭｅＯ２ＣＣ５Ｈ４）（ＣＯ）２Ｍｏ〕－〔（η＾５－ＭｅＯ２ＣＣ５Ｈ４）（ＣＯ）２Ｗ〕Ｆｅ（ＣＯ）３（μ３－Ｓ）的分子结构及晶体结构。晶体属Ｐ１空间群，晶胞参数ａ＝０．８７１６２（５）ｎｍ，ｂ＝０．８     

氧缺位铁酸盐的制备及结构与还原行为的研究

在３５８Ｋ下用２００ｍｌ／ｍｉｎ的空气氧化碱性悬浮液合成了ＭＦｅ_２Ｏ_（４＋δ）（δ≥０，Ｍ＝Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ），并在５７３Ｋ下用４０ｍｌ／ｍｉｎ的Ｈ_２还原ＭＦｅ_２Ｏ_（４＋δ）制备了氧缺位铁酸盐ＭＦｅ_２Ｏ_（４－δ）（δ＞０）。用ＸＲＤ、Ｍｓｓｂａｕｅｒ谱等测试方法对铁酸盐的结构进行了表征，考察了铁酸盐的组成及第二金属组分（Ｃｏ、Ｎｉ、Ｍｎ）对铁酸盐还原性能的影响。在Ｈ_２还原３ｈ内，铁酸盐氧缺位程度随还原时间增加而增大，晶格常数也相应增大；５ｈ以上，铁酸盐将被还原为ＭＯ－ＦｅＯ或α－Ｆｅ，晶格常数几乎不变。按Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ顺序，ＭＯ与ＦｅＯ的相互作用能力、ＭＯ－ＦｅＯ固溶体的稳定性及铁酸盐还原为ＭＯ－ＦｅＯ的能力均增强，ＭＯ－ＦｅＯ进一步还原为α－Ｆｅ的能力却减弱。     

Skeleton Vibrations and Force Constants of ［Fe_2Cr（μ_3－O）（glycine）_6（H_2O）_3］（NO_3）_7．3H_2O

ＳｋｅｌｅｔｏｎＶｉｂｒａｔｉｏｎｓａｎｄＦｏｒｃｅＣｏｎｓｔａｎｔｓｏｆ［Ｆｅ_２Ｃｒ（μ_３－Ｏ）（ｇｌｙｃｉｎｅ）_６（Ｈ_２Ｏ）_３］（ＮＯ_３）_７．３Ｈ_２ＯＺｈａｎｇＬｉｎ－Ｎａ，ＬｉｎＺｈｅｎｇ－Ｙａｎ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏ...     

An X-ray absorption spectroscopic study on mixed conductive La0.6Sr0.4Co0.8Fe0.2O(3-δ) cathodes. I. Electrical conductivity and electronic structure

The electrical conduction mechanism of mixed conductive perovskite oxides, La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3-δ), for cathode materials of solid oxide fuel cells has been investigated from electronic structural changes during oxygen vacancy formation. La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3-δ) was annealed under various oxygen partial pressures p(O(2))s at 1073 K and quenched. Iodometric titration indicated that the oxygen nonstoichiometry of La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3-δ) depended on the annealing p(O(2)), with more oxygen vacancies introduced at lower than at higher p(O(2))s. X-Ray absorption spectroscopic measurements were performed at the O K-, Co L-, Fe L-, Co K-, and Fe K-edges. The valence states of the Co and Fe ions were investigated by the X-ray absorption near edge structure (XANES) at the Co and Fe L(III)-edges. While the Fe average valence was almost constant, the valence of the Co ions decreased with oxygen vacancy introduction. The O K-edge XANES spectra indicated that electrons were injected into the Co 3d/O 2p hybridization state with oxygen vacancy introduction. Both absorption edges at the Co and Fe K-edge XANES shifted towards lower energies with oxygen vacancy introduction. The shift at the Co K-edge resulted from the decrease in the Co average valence and that at the Fe K-edge appeared to be caused by changes in the coordination environment around the Fe ions. The total conductivity of La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3-δ) decreased with decreasing p(O(2)), due to a decreasing hole concentration.     

无气相氧条件下La0.8Sr0.2Fe0.9Co0.1O3钙钛矿氧化物的氧物种直接氧化甲烷

以La0.8Sr0.2Fe0.9CO0.1O3钙钛矿氧化物作氧载体,采用连续流动反应和连续顺序Redox反应考察了氧物种氧化甲烷的反应性能.结果表明,连续流动反应中La0.8Sr0.2Fe0.9CO0.1O3氧化物的氧物种能选择氧化甲烷生成合成气.在适宜的再氧化条件下,通过连续顺序Redox反应实现了La0.8Sr0.2Fe0.9CO0.1O3氧化物的氧物种氧化甲烷连续生成合成气,消耗的氧物种可通过与气相氧反应而得到补充.但随着Redox反应的进行,氧化物的持续供氧性能下降,钙钛矿结构被破坏.     

Remarkable dependence of electrochemical performance of SrCo0.8Fe0.2O(3-δ) on A-site nonstoichiometry

SrCo(0.8)Fe(0.2)O(3-δ) is a controversial material whether it is used as an oxygen permeable membrane or as a cathode of solid oxide fuel cells. In this paper, carefully synthesized powders of perovskite-type Sr(x)Co(0.8)Fe(0.2)O(3-δ) (x = 0.80-1.20) oxides are utilized to investigate the effect of A-site nonstoichiometry on their electrochemical performance. The electrical conductivity, sintering property and stability in ambient air of Sr(x)Co(0.8)Fe(0.2)O(3-δ) are critically dependent on the A-site nonstoichiometry. Sr(1.00)Co(0.8)Fe(0.2)O(3-δ) has a single-phase cubic perovskite structure, but a cobalt-iron oxide impurity appears in A-site cation deficient samples and Sr(3)(Co, Fe)(2)O(7-δ) appears when there is an A-site cation excess. It was found that the presence of the cobalt-iron oxide improves the electrochemical performance. However, Sr(3)(Co, Fe)(2)O(7-δ) has a significant negative influence on the electrochemical activity for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The peak power densities with a single-layer Sr(1.00)Co(0.8)Fe(0.2)O(3-δ) cathode are 275, 475, 749 and 962 mW cm(-2) at 550, 600, 650 and 700 °C, respectively, values which are slightly lower than those for Sr(0.95)Co(0.8)Fe(0.2)O(3-δ) (e.g. 1025 mW cm(-2) at 700 °C) but much higher than those for Sr(1.05)Co(0.8)Fe(0.2)O(3-δ) (e.g. only 371 mW cm(-2) at 700 °C). This remarkable dependence of electrochemical performance of the Sr(x)Co(0.8)Fe(0.2)O(3-δ) cathode on the A-site nonstoichiometry reveals that lower values of electrochemical activity reported in the literature may be induced by an A-site cation excess. Therefore, to obtain a high performance of Sr(x)Co(0.8)Fe(0.2)O(3-δ) cathode for IT-SOFCs, an A-site cation excess must be avoided.     

高性能镓酸镧基电解质燃料电池

制备并用多种电化学方法研究了LaGaO3基高性能中温固体氧化物燃料电池的电极和电解质材料，组装出了高性能单电池.实验发现， Co掺杂的La0.8Sr0.2Ga0.8Mg0.2O3电解质中， Co含量的增加显著提高了电解质的氧离子电导率，电解质的氧迁移数略有减小，是非常好的中、低温燃料电池电解质.钴掺杂的电解质不仅显著减小了电池的欧姆电阻，而且减小了电池的阴、阳极极化过电位.以La0.8Sr0.2Ga0.8Mg0.11Co0.09O3为电解质时电池在1073、973、873 K下的最大输出功率密度分别达到1.77、0.92、0.41 W•cm－2，是非常有前景的电池体系.     

中温固体氧化物燃料电池复合阴极Pr0.6-zSr0.4Co0.8Fe0.2O3-δ-SDC性能研究

采用改进的溶胶-凝胶法合成固体氧化物燃料电池阴极系粉体Pr0.6-zSr0.4Co0.8Fe0.2O3-δ(PSCF)(z=0,0.02,0.05,0.1)。使用X射线衍射(XRD)、扫描电子显微镜(SEM)对其相结构与形貌进行了分析,结果表明:900℃以上焙烧后的阴极粉体Pr0.6-zSr0.4Co0.8Fe0.2O3-δ(z=0,0.02,0.05,0.1)为单一的钙钛矿结构。1000℃烧结的样品内粒子分布比较均匀,且颗粒内部存在一定程度的空隙,并与电解质附着情况良好。用直流四电极法测试阴极体系样品在400～750℃的电导率,发现各试样混合离子电子电导率均高于786 S.cm-1,能够满足固体氧化物燃料电池对阴极电导率的要求。用交流阻抗法测定PSCF-Ce0.8Sm0.2O1.9体系样品的阻抗谱,得到1000℃烧结的阴极体系对称电池在测试温度为750℃z=0,z=0.02,z=0.05时的极化电阻分别为0.041,0.040,0.034Ω.cm-2。     

Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9Co0.1O3 perovskite oxides as oxygen carrier for partial oxidation of methane

Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9Co0.1O3 perovskite oxides as oxygen cartier for partial oxidation of methane in the absence of gaseous oxygen was investigated by continuous flow reaction and sequential redox reaction. Methane was oxidized to syngas with high selectivity by oxygen species of perovskite oxides in the absence of gaseous oxygen. The sequential redox reaction revealed that the structural stability and continuous oxygen supply in redox re-action decreased over La0.8Sr0.2Fe0.9Co0.1O3 oxide, while LaFeO3 and Lao.sSro.2FeO3 exhibited excellent structural stability and continuous oxygen supply.     

Optical,mechanical and electrical properties of LSCF–SDC composite cathode prepared by sol–gel assisted rotary evaporation technique

Journal of Sol-Gel Science and Technology - La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) is a perovskite-type oxide that exhibits excellent mixed ionic–electronic conducting properties and is a...     

纳米La0.8A’0.2Mn1-xCuxO3（A’=Ce and/or Sr）的制备、表征及其高效催化NO+CO的性能研究

采用柠檬酸-溶胶凝胶法制得钙钛矿型复合氧化物La0.8Ce0.2Mn1-xCuxO3(x=0.2,0.3,0.4),La0.8Sr0.2Mn0.6Cu0.4O3,La0.8Ce0.1Sr0.1Mn0.6 Cu0.4 O3,并采用X射线衍射(XRD)、扫描电镜(SEM)、比表面积(BET)、X射线光电子能谱(XPS)对其进行表征,测试了复合氧化物对CO+NO的催化活性。结果表明:La0.8Ce0.1Sr0.1Mn0.6Cu0.4O3催化活性最好,150℃时CO转化率91.8%,300℃时NO转化率100%;对于La0.8Ce0.2Mn1-xCuxO3(x=0.2,0.3,0.4),比表面积和颗粒的大小及分散度是影响催化活性的主要因素;对于La0.8Ce0.2Mn0.6Cu0.4O3,La0.8 Sr0.2 Mn0.6 Cu0.4 O3,La0.8 Ce0.1 Sr0.1 Mn0.6 Cu0.4 O3,催化剂的组成是影响催化活性的关键因素。     

高性能Sm0.5Sr0.5CoO3阴极的制备与表征

用固相合成法合成了Sm0.5Sr0.5CoO3 (SSC)中温固体氧化物燃料电池阴极材料.以La0.9Sr0.1Ga0.8Mg0.2O3为电解质,利用多种技术考察了不同温度(1173～1373 K)焙烧的SSC阴极,以及1173 K 焙烧、掺杂La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)或La0.8Sr0.2Ga0.8Mg0.09Co0.11O3 (LSGMC11)高氧离子电导材料的复合SSC阴极.SEM的结果显示,随着电极焙烧温度的增加,电极的颗粒度增大,孔隙度减小；LSGMC5、LSGMC11的掺杂对电极微观结构影响不大.交流阻抗和极化实验的结果表明,SSC电极的活性随电极焙烧温度的增加而减小,电极的最佳焙烧温度在1173 K左右；掺杂了LSGMC5或LSGMC11的复合SSC电极的活性以及稳定性显著高于SSC电极.     

用湿化学法制备Sm0.5Sr0.5CoO3-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3复合阴极及其性能表征

用湿化学法制备了Sm0.5Sr0.5CoO3(SSC)－La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)中温固体氧化物燃料电池复合阴极材料，其中SSC用甘氨酸－硝酸盐法合成，LSGMC5用柠檬酸盐法合成。XRD结果表明，甘氨酸－硝酸盐法制备的SSC在焙烧温度大于1223K即表现为单一的钙钛矿结构。随焙烧温度的升高，SSC粉末颗粒增大,导致含有高温烧结SSC的电极与电解质界面结合变差。采用多种技术考察了利用不同温度（1173－1373K）预烧的SSC粉末制备的SSC-LSGMC5阴极上进行的氧还原反应。结果表明，SSC-LSGMC5复合电极的性能显著依赖于电极中SSC粉末的预烧温度，当SSC粉末焙烧温度在1223K附近时，具有最小的欧姆电阻以及氧还原反应极化电阻，1A· cm-2电流密度下的极化过电位为0.077 V。