Constructing a multifunctional mesoporous composite of metallic cobalt nanoparticles and nitrogen-doped reduced graphene oxides for high-performance lithium-sulfur batteries

Electrochemical properties of lithium-sulfur(Li-S)batteries are mainly hindered by both the insulating nature of elemental sulfur(i.e.,molecular S8)and the shuttling effect or sluggish redox kinetics of lithium polysulfide intermediates(Li_(2)S_(n),3≤n≤8).In this paper,a three-dimensional mesoporous reduced graphene oxide-based nanocomposite,with the embedding of metallic Co nanoparticles and the doping of elemental N(Co/NrGO),and its simply ground mixture with powdered S at a mass ratio of 1:6(Co/NrGO/S)are prepared and used as cathode-/separator-coated interlayers and working electrodes in assembled Li-S cells,respectively.One of the effective cell configurations is to paste composite Co/NrGO onto both the S-loading cathode and separator,showing good cycling stability(1070mAh g^(−1) in the 100th cycle at 0.2 C),highrate capability(835mAh g^(−1),2.0 C),and excellent durability(905mAh g^(−1) in the 250th cycle at 0.5 or 0.2 C).Compared with the experimental results of Co-absent NrGO,electrochemical properties of various Co/NrGO-based cell configurations clearly show multiple functions of Co/NrGO,indicating that the absence of Co/NrGO coatings and/or Co nanoparticles may be inadequate to achieve superior S availability of assembled Li-S batteries.

Surfactant-free oil/water and bicontinuous microemulsion composed of benzene,ethanol and water

Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel suffactant-free microemulsion（denoted as SFME） composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water（O/W） microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy（FF-TEM） observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.

The photoluminescence of Co-Al-layered double hydroxide

我们报导纯 Co-Al-layered 双氢氧化物(LDH ) 的新光行为。没有任何荧光灯的物质， Co-Al-LDH 样品能射出荧光，这被发现设置。它的刺激光谱在波长附近显示出一座最大的山峰 370 nm，最大的排放山峰在 430 nm 出现， Co-Al-LDH 样品的光致发光颜色是蓝的。这个新光性质将被期望在光材料地里扩大 LDH 的潜在的应用。

Formation of wormlike mi-celles in anionic surfactant AES aqueous solutions

The growth and structure of anionic micelles of sodium dodecyl trioxyethylene sulfate (AES) in the presence of multivalent counterion Al3+ were investigated by means of dynamic rheological methods. It has been obtained by themeasurements of shear viscosity, complex viscosity anddynamic moduli, as well as the application of Cox-Merz rule and Cole-Cole plot that wormlike micelle and networkstructure could be formed in AES/AlCl3 aqueous solutions. The structure was of a character of nonlinear viscoelasticfluid and departure from the simple Maxwell model. Thetechnique of freeze-fracture transmission electronmicroscopy (FF-TEM) was also used to confirm theformation of this interesting structure.

Effect of Electrolytes and Polymers on the Thixotropy of Mg-AI-Layered Double Hydroxides/Kaolinite Dispersions

The effect of electrolytes （NaCl and CaCl2） and polymers （CPAM and HPAM） on the thixotropy of Mg-Al-layered double hydroxide （LDHs）/kaolinite dispersions has been investigated. It was observed that the type of thixotropy in LDH/kaolinite dispersions may be affected by NaCl, but not by CaCl2 in range of concentration of interest. The type of thixotropy in LDH/kaolinite dispersion with R=0 transformed from positive thixotropy to complex thixotropy and at last positive thixotropy again with the concentration of NaC1 in range of 0.00-0.10 mol·L^-1; the type of thixotropy in LDHs/kaolinite dispersions with R = 0.25 transformed from complex thixotropy to positive thixotropy and then complex thixotropy again with the concentration of NaC1 in range of 0.00-0.10 mol·L^-. The type of thixotropy in LDH/kaolinite dispersion with R=0 may be not affected by cationic polyacrylamide （CPAM） and hydrolyzed polyacrylamide （HPAM）; but the LDHs/kaolinite dispersions with R=0.25 transformed from complex thixotropy to positive thixotropy with the both polymers concentration in range of interest, which indicated that the microstructure of the dispersion changed from weak folc sediments structure to steric network structure.

Evaluation of Intrinsic Ionization and Complexation Constants of TiO2 and Mg-Fe Hydrotalcite-like Compounds

The intrinsic surface reaction constants, pKa1^int, pKa2^int, p^＊KC^int and p^＊KA^int , were evaluated by a modifieddouble extrapolation （MDE） for TiO2 without structural charge and Mg-Fe hydrotalcite-like compounds （HTlc） with structural charge, respectively. The results of intrinsic surface reaction constants for TiO2 were compared with those obtained by class double extrapolation （CDE） in literature. Furthermore, the values of intrinsic surface reaction constants obtained by MDE were used to simulate the charging behaviors of the materials. The following conclusions were obtained. For TiO2 without structural charge, the pKa1^int and pKa2^int evaluated by MDE are equal to those by CDE, however the p^＊KC^int and p^＊KA^int evaluated by MDE are much different from those by CDE. In principle, the results of the p^＊KC^int and p^＊KA^int evaluated by MDE are more accurate than those by CDE. The values of intrinsic surface reaction constants obtained by MDE can excellently simulate the charging curves for TiO2 with the triple layer model （TLM）. For HTlc with positive structural charge, the results of ^＊KC^int=0 and ^＊KA^int →∞ were obtained by MDE, which means the inert electrolyte chemical binding does not exist; the point of zero net charge （PZNC） of c-independence also exist as the same as solid without structural charge, and the PHPZNC obtained by the acid-base titration can excellently be simulated and the surface charging tendency can be simulated to a great extent using the pKa1^int and pKa2^int evaluated by MDE and the diffuse layer model （DLM）.

Gold carbene chemistry from diazo compounds

Diazo compounds are generally used as carbene precursors. Traditionally, dirhodium, copper and iron catalysts were used to decompose diazo compounds to form the key metal carbene intermediates. Recently, the gold catalysts have been developed as a unique type of metal catalyst to decompose diazo compounds. The derived gold carbene showed much different characters comparing with other transition metal carbenes. They could go through a series of cycloaddition, insertion and coupling reactions. Here, the recent progress of the gold carbene chemistry from diazo compounds was reviewed, including the scope of reactions,mechanism and synthetic applications.

Synthesis of 4H-chromenes by silver(Ⅰ)-catalyzed cycloaddition of ortho-quinone methides with N-allenamides

Chromenes represent an important class of six-membered heterocycles and have drawn tremendous attention in recent years. In this article, we report a convenient and practical synthesis of this heterocycle by a silver(I)-catalyzed cycloaddition reaction between in situ generated ortho-quinone methides and N-allenamides. Diverse 4H-chromenes were synthesized in good to excellent yields under very mild conditions.