MoO3 /SiO2复合正极材料的制备及电化学性能研究

本文通过化学沉淀-热处理方法制备了MoO3正极材料,并通过正硅酸乙酯(TEOS)的水解在MoO3的表面包覆SiO2得到MoO3/SiO2复合正极材料[wSiO2/wMoO3=8%],对制备材料的结构和电化学性能进行了表征。结果表明,得到的MoO3为纯的正交相结构,片状MoO3的粒径大小约200～500 nm,厚度约50 nm。片状颗粒倾向于堆积在一起形成层状结构。在MoO3的表面包覆了一层无定形的SiO2。在电压范围1.5～4.0 V的条件下,以0.1C倍率进行恒电流充放电测试,MoO3/SiO2样品的首次放电容量为332.7 mAh.g-1,库仑效率87.6%。循环20次后,放电容量降为277.7 mAh.g-1。SiO2的包覆降低了MoO3正极材料的初始容量,但循环性能得到了提高。     

A new organic‐inorganic molybdenum arsenate complex based on [(CuO6)(As3O3)2Mo6O18]4‐ cluster as secondary building units

A new molybdenum arsenate, [Cu(imi)₂]₂[(CuO₆)(As₃O₃)₂Mo₆O₁₈][Cu(imi)₂]₂ ( 1 ) (imi = C₃N₂H₄), has been synthesized under mild hydrothermal conditions, and characterized by elemental analysis, IR, thermogravimetric analyses, and single‐crystal X‐ray diffraction analysis. The polyanion framework derives from the Anderson structure in which the central octahedron is filled up by a copper (II), and is capped on both sides by two cyclic As₃O₆ groups. The countercations contain bisupported [Cu(imi)₂]⁺ complex cations and two free [Cu(imi)₂]⁺ complex cations. The electrochemical behavior of 1 ‐modified carbon paste electrode ( 1 ‐CPE) has been studied in detail. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

丙烷选择氧化单斜 TeMo5O16 催化剂中钒掺杂的作用

 研究了在不同温度下 V 掺杂的单斜 TeMo5O16 催化剂上丙烷选择氧化反应性能. 结果发现, 在保持 TeMo5O16 相结构基本不变的条件下, V 的掺杂提高了催化剂的活性以及丙烯和丙烯醛等脱氢与选择氧化产物的收率. 通过程序升温表面反应、拉曼光谱、X 射线光电子能谱、X 射线衍射、程序升温还原和热重分析等手段对其原因进行了探讨. 结果表明, V 的掺杂引起催化剂表面金属–氧键发生变化, 提高了表面氧化还原中心的活性, 增加了酸性中心数目, 从而提高了催化剂活化丙烷能力. 同时, 较高的 V 掺杂量可以提高催化剂体相中晶格氧参与氧化还原的能力.     

Syntheses, Structure Characterizations and Fluorescent Properties of Two Reduced Molybdenum (V) Phosphates Functionalized by Zinc Coordination Complexes

Two new materials built from reduced molybdenum (V) phosphates as building blocks and zinc coordination complexes as linkers, (H₃O)₂[Zn(2,2′-bpy)]₄[Zn(H₂O)]₂[Zn(HPO₄)₂ (PO₄)₆(MoO₂)₁₂(OH)₆] · 6H₂O (2,2′-bpy=2,2′-bpyridine) 1 and [Zn(phen)(H₂O)₂]₂[Zn(phen) (H₂O)]₂[Zn(H₂O)]₂[Zn(HPO₄)₄ (PO₄)₄(MoO₂)₁₂ (OH)₆] · 7H₂O (phen=1,10-phenanthroline) 2, have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 is a new 3-D structure which constructed from Zn[P₄Mo₆]₂ dimers bonded together with [Zn(2,2′-bpy)] coordination complexes and [Zn(H₂O)] fragments. In compound 2, the Zn[P₄Mo₆]₂ dimeric units are linked by [Zn(phen)(H₂O)] coordination complexes and [Zn(H₂O)] fragments to form a new 2-D framework. The fluorescent activities of compounds 1 and 2 were reported. The crystal data for the two compounds are the following: 1, triclinic, P−1, a=13.036(3) ?, b=13.765(3) ?, c=14.459(3) ?, , Z=1; 2, triclinic, P−1, a=12.708(3) ?, b=14.016(3) ?, c=14.646(3) ?, , Z=1.Dedicated to Professor Michael T. Pope on the occasion of his retirement.     

Quantification of steric interactions in phosphine ligands from single crystal X-ray diffraction data. Crystal structures of (η-C5H4Me)Mo(CO)2(PR3)I (R3 = PhMe2, PhEt2, Et3)

Distorted square pyramidal complexes of molybdenum (η⁵-C₅H₄Me)Mo(CO)₂(PR₃)I (R₃ = PhMe₂ (2a); PhEt₂ (3a) and Et₃ (4a)) have been synthesized and the structures of the lateral (cis) isomers have been determined by X-ray diffraction. The cone (Θ) and solid (Ω) angles as well as the angular profiles of the phosphine ligands in the complexes have been computed using the program steric. Values for the crystallographic cone and solid angles calculated for 2a, 3a and 4a are Θ (129°, 135° and 139°) and Ω (2.73, 2.99 and 2.93 sr), respectively. A search of the Cambridge Structural Database (CSD) was made for piano stool, 5- and 6-coordinate complexes containing the title phosphine ligands. Results from this study show a wide range of sizes for each of the ligands and even the seemingly simple PPhMe₂ ligand exhibited a wide range of values for the cone (113-137°) and solid (2.49-3.07 sr) angles. These observations have been rationalized and related to the possible group conformations from the crystallographic data.     

高比表面积磷化钼的制备

 利用柠檬酸与钼的螯合作用,采用柠檬酸-程序升温还原联合法制备了高比表面积的磷化钼,并考察了制备条件的影响. 结果表明,当柠檬酸与钼的摩尔比为2.0时,得到的磷化钼比表面积高达122.0 m2/g. 采用该方法还可制得较高比表面积的磷化镍和磷化钴.     

Oxygenation of sulfides catalysed by SBA‐15‐immobilized molybdenum(VI) complex of a bis(phenol) diamine ligand using aqueous hydrogen peroxide as a green oxidant

A highly efficient and reusable molybdenum‐based catalyst has been synthesized by covalent grafting of a bis(phenol) diamine ligand, namely 2‐(((2‐bromoethyl)(2‐((3,5‐di‐tert‐butyl‐2‐hydroxybenzyl)amino)ethyl)amino)methyl)‐4,6‐di‐tert‐butylphenol, onto functionalized ordered mesoporous silica (SBA‐15) followed by complexation with MoO₂(acac)₂. The resulting organic–inorganic hybrid material was found to be a highly effective catalyst for oxygenation of various sulfides to their corresponding sulfoxides or sulfones. The catalyst was characterized using transmission and scanning electron microscopies, X‐ray photoelectron, Fourier transform infrared and atomic absorption spectroscopies, Brunauer–Emmett–Teller surface area analysis and thermogravimetric analysis. Mild reaction conditions, high selectivity and easy recovery and reusability of the catalyst render the presented protocol very useful for addressing industrial needs and environmental concerns.