0/1/2维混合纳米形貌V2 O5的制备与储锂性能

以P123为结构导向剂,采用溶胶-凝胶法结合冷冻干燥技术制备了0/1/2维混合纳米形貌的正交相V₂O₅电极活性材料.利用XRD和SEM表征了样品的结构和形貌,通过循环伏安法、恒流充放电和交流阻抗谱测试研究了样品的储锂性能.结果显示,这种0/1/2维混合纳米形貌V₂O₅具有较高的储锂容量、优异的电化学循环稳定性和出色的大倍率充放电性能,在1 A/g电流密度下循环500次后放电比容量稳定在117.5 mA·h/g,容量保持率为94.4%,在5 A/g大电流密度下,其放电比容量仍保持在88.2 mA·h/g,性能明显优于未添加P123制备的2D片状V₂O₅材料.     

Exponentially fitted multi-derivative linear methods for the resonant state of the Schrödinger equation

A new family of exponentially fitted P-stable one-step linear methods involving several derivatives for the numerical integration of the Schrödinger equation are obtained. Numerical results are reported to show the efficiency and robustness of the new methods specially adapted to the integration of the radial time-independent Schrödinger equation for large energies. Error analysis is carried out and the asymptotic expressions of the local errors for large energies explain the results of the numerical experiments on the resonance problem.     

Syntheses,Structures and Characterization of Four Metal‐Organic Frameworks constructed by 2,2′,6,6′‐Tetramethoxy‐4,4′‐biphenyldicarboxylic Acid

Four metal‐organic frameworks (MOFs), {[Mn_3.5L(OH)(HCOO)₄(DMF)] · H₂O} ( 1 ), {[In_2.5L₂O(OH)_1.5(H₂O)₂] · DMF · CH₃CN · 2H₂O} ( 2 ), {[Pb₄L₃O(DMA)] · CH₃CN} ( 3 ), and {[LaL(NO₃)(DMF)₂] · 2H₂O} ( 4 ) were synthesized by utilizing the ligand 2,2′,6,6′‐tetramethoxy‐4,4′‐biphenyldicarboxylic acid (H₂L) via solvothermal methods. All MOFs were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction, thermogravimetric analysis, and infrared spectroscopy. In 1 , the Mn²⁺ ions are interconnected by formic groups in situ produced via DMF decomposition to form a rare 2D macrocyclic plane, which is further linked by L^2– to construct the final 3D network. In 2 , 1D zip‐like infinite chain is formed and then interconnected to build the 3D framework. In 3 , a [Pb₆(μ₄‐O)₂(O₂C)₁₀(DMA)₂] cluster with a centrosymmetric [Pb₆(μ₄‐O)₂]⁸⁺ octahedral core is formed in the 3D structure. In 4 , the La³⁺ ions are connected with each other through carboxylate groups of L^2– to generate 1D zigzag chain, which is further linked by L^2– to construct a 3D network with sra topology. Solid photoluminescence properties of 3 and 4 were also investigated.     

Ni离子替位掺杂TiO2增强光热化学循环还原CO2研究

利用溶胶凝胶法（Sol-gel）制备纯TiO₂（ST）及Ni掺杂TiO₂（NT）纳米薄膜,将其应用在光热化学循环（PTC）还原CO₂中进行机理研究,并与商用P25（PT）进行对比.结果表明利用NT进行CO₂还原,每个循环得到的平均CO产率最高为5.30 μmol/g-cat,分别是利用ST与PT得到CO产率的3.13倍与2.28倍.利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线能量色散谱（EDXS）及X射线衍射技术（XRD）研究样品的物质组成、晶体结构与形貌.稳态与时间分辨固体光致发光光谱（PL）、紫外可见漫反射光谱（UV-vis DRS）和X射线光电子能谱（XPS）被用来进行材料光学性能及表面态检测,从而得到反应中激发电子转移机制.利用第一性原理计算研究材料表面氧空位形成能、态密度（DOS）及分态密度（PDOS）.结合实验表征与理论计算,理清控制PTC反应进行的关键因子.     

A heterometal (Pd–Pb) organic framework: synthesis,structure and heterogeneous catalytic application

A heterometallic organic framework {Pb[Pd(bpydc)Cl₂]DMF}_n ( 1 ) (H₂bpydc = 2,2′‐bipyridine‐5,5′‐dicarboxylic acid) was synthesized via a one‐pot solvothermal method and characterized using thermogravimetric analysis, X‐ray photoelectron spectroscopy as well as powder and single‐crystal X‐ray diffraction. The crystal structure of 1 indicates that, in metalloligand Pd(bpydc)Cl₂, every Pd atom adopts a square planar coordination mode with two chloride ions and two nitrogen atoms from bpydc, and the carboxyl groups of Pd(bpydc)Cl₂ connect Pb atoms to form a one‐dimensional chain along the crystallographic a‐axis, which is interlinked via metalloligands to form a two‐dimensional layer structure. This complex is highly active, stable and recyclable as a catalyst for the Suzuki–Miyaura and Heck reactions of a wide range of aryl halides including electron‐rich and electron‐poor aryl iodides/bromides, affording the corresponding products in good to excellent yields. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO3

In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO₃ and Bi_0.85Dy_0.15FeO₃ have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO₃ samples are obviously broadened after magnetic annealing, whereas those of Bi_0.85Dy_0.15FeO₃ samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO₃ samples, the remnant polarizations (P_r) are suppressed; in contrast, for Bi_0.85Dy_0.15FeO₃ samples, P_r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed.     

A direct and practical approach for the synthesis of Au(I)-NHC complexes from commercially available imidazolium salts and Au(III) salts

A direct and practical approach for the synthesis of Au(I)-NHC complexes from imidazolium salts and commercially available aurate salt (MAuCl₄·2H₂O) is described. The reaction proceeded without sacrificing carbene transfer agent (Ag₂O) or using highly sensitive free NHC.