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氢的存储是氢能利用的关键,利用多孔材料的胶囊化作用存储氢气具有独特优点。本文简要阐述了胶囊化形成的原因,重点介绍了胶囊化储氢所用的几种多孔材料及其特点,包括沸石分子筛、金属配位化合物、玻璃微球和球碳及其衍生物。总结了近年来国内外学者利用多孔材料胶囊化作用储氢的研究进展,并从操作条件、对材料的要求、需要克服的能垒等方面分析了胶囊化储氢与物理吸附储氢的差异,进而对今后胶囊化储氢的应用与发展做出了展望。 相似文献
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用密度泛函理论(DFT)的B3LYP方法,在6-311G、6-311+G(d)、6-311++G(d, p) 基组水平上研究了CH3CF2O2与HO2自由基反应机理. 结果表明, CH3CF2O2与HO2自由基反应存在两条可行的通道. 通道CH3CF2O2+HO2→IM1→TS1→CH3CF2OOH+O2的活化能为77.21 kJ•mol-1,活化能较低,为主要反应通道,其产物是O2和CH3CF2OOH. 这与实验结果是一致的;而通道CH3CF2O2+HO2→IM2→TS2→IM3→TS3→IM4+IM5→IM4+TS4→IM4+OH+O2→TS5+OH+O2→CH3+CF2O+OH+O2→CH3OH+CF2O+O2的控制步骤活化能为93.42 kJ•mol-1,其产物是CH3OH、CF2O和O2. 结果表明这条通道也能发生,这与前人的实验结果一致. 相似文献
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为研究重铬酸钠(Na2Cr2O7)对CO2溶解的影响, 本文在带有搅拌的气液相高压平衡釜内, 采用静态法测定了温度在313.2-333.2 K, 压力在0.1-1.9 MPa 范围内, 重铬酸钠浓度分别为0、0.361、0.650、0.901 mol·kg-1 时, CO2 在Na2Cr2O7溶液中的溶解度. 结果表明: (1) Na2Cr2O7对CO2 的溶解有盐析效应; (2) CO2 在Na2Cr2O7溶液中的溶解符合亨利定律, 并且CO2溶解度是温度和Na2Cr2O7浓度的函数, 且用改进的Setschenow方程和Peng-Robinson-Pitzer (PR-Pitzer)方程拟合了在此温度、压力及重铬酸钠浓度范围内的实验数据, 拟合效果较好, 并且其平均相对误差分别为4.24%和3.32%. 相似文献
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采用热分解法制备了一种新型高效析氯阳极Ti/RuO2-IrO2-SnO2-Sb2O5,将其应用于农村饮用水消毒频繁停开、低电解液浓度的特殊工况下,并与Ti/RuO2-SnO2-Sb2O5、Ti/RuO2-TiO2、Ti/RuO2-TiO2-IrO2三种析氯阳极进行性能对比。通过SEM、EDS、XRD等方法表征测试阳极表面形貌、元素及组成,考察了氯化钠浓度、电流密度、停开频率对阳极析氯效果和寿命的影响。研究发现,Ti/RuO2-IrO2-SnO2-Sb2O5阳极活性强、稳定性高;阳极涂层各组分高度融合为固溶体,结构致密,稳定性强;在15 g·L-1 NaCl、400 A·m-2电流密度、20℃条件下,Ti/RuO2-IrO2-SnO2-Sb2O5阳极电解的电流效率达到91.55%;频繁停开、强化电解条件下寿命达到231 h,是Ti/RuO2-TiO2阳极的77倍,预估在400 A·m-2电流密度下能够使用20年。 相似文献
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Martin Sahlberg Yvonne Andersson 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(3):i7-i8
Scandium magnesium gallide, Sc2MgGa2, and yttrium magnesium gallide, Y2MgGa2, were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo2FeB2‐type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc2MgGa2 was determined from single‐crystal diffraction intensities and the isostructural Y2MgGa2 was identified from powder diffraction data. 相似文献
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On Dialkali Metal Dichalcogenides β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 and Rb2Te2 The first presentation of pure samples of α- and β-Rb2S2, α- and β-K2Te2, and Rb2Te2 is described. Using single crystals of K2S2 and K2Se2, received by ammonothermal synthesis, the structure of the Na2O2 type and by using single crystals of β-Na2S2 and β-K2Te2 the Li2O2 type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na2O2 type to the Li2O2 type will be explained by means of the examples α-/β-Na2S2 and α-/β-K2Te2. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb2S2 is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence. 相似文献
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Marina I. Naumova Natalia V. Kuratieva Nina V. Podberezskaya Dmitry Yu. Naumov 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(5):i53-i55
The structures of the hypophosphites KH2PO2 (potassium hypophosphite), RbH2PO2 (rubidium hypophosphite) and CsH2PO2 (caesium hypophosphite) have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous. 相似文献
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Paul-Louis Fabre Dominique de Montauzon René Poilblanc 《Transition Metal Chemistry》1987,12(5):434-440
Summary The ability of [MoS4]2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe2+. The present study has been restricted to linear complexes such as (NEt4)2 [Cl2FeS2MoS2] and (NEt4)2[Cl2FeS2MoS2FeCl2]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS2, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl2]2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl4Fe2MoS4]2–[Cl2FeMoS4]2–+FeCl2. The equilibrium constant, KD, was evaluated by differential pulse polarography. KD is tightly related to the donor number of the solvent. 相似文献
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[reaction: see text] Fluoranthene 2 and heptacycle 3 are easily accessible from the reaction of diyne 1 and norbornadiene (NBD) in the presence of the rhodium catalyst. The unusual [(2+2)+(2+2)] adduct 3 was confirmed by the X-ray crystal structure analysis. 相似文献
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A. -F. Shihada A. A. Said R. Al Qasmi 《Journal of Thermal Analysis and Calorimetry》1994,42(6):1313-1318
TG and DTA studies on Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2 were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading
to the formation of Sn3(PO4)2 as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination
reactions were proposed. 相似文献
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Marina I. Naumova Natalia V. Kuratieva Dmitry Yu. Naumov Nina V. Podberezskaya 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):i14-i16
The structures of isomorphous monoclinic strontium and lead bis(dihydrogenphosphate), Sr(H2PO2)2 and Pb(H2PO2)2, and orthorhombic barium bis(dihydrogenphosphate), Ba(H2PO2)2, consist of layers of hypophosphite anions and metal cations exhibiting square antiprismatic coordination by O atoms. The Sr and Pb atoms are located on sites with point symmetry 2, and the Ba atoms are on sites with point symmetry 222. Within the layers, each anion bridges four metal cations. 相似文献