Intermolecular and intramolecular coupling in charged monosubstituted hexapyrrolylbenzenes

Cyclic voltammetric and UV/vis and EPR spectroelectrochemical studies of new synthesized series of pyrrolylbenzenes indicate different oxidation products depending on the number of pyrrole units on the phenyl ring and on the pyrrole substitution. Both intra- and intermolecular coupling of charged monosubstituted hexapyrrolylbenzenes is evidenced from cyclovoltammetric and spectroelectrochemical studies. The optical and electrochemical properties as well as the extent of the intermolecular coupling strongly depend on the and β substitution of 1-N-pyrrolyl group.     

Metal Cations in Efficient Perovskite Solar Cells: Progress and Perspective

Metal halide perovskite solar cells (PVSCs) have revolutionized photovoltaics since the first prototype in 2009, and up to now the highest efficiency has soared to 24.2%, which is on par with commercial thin film cells and not far from monocrystalline silicon solar cells. Optimizing device performance and improving stability have always been the research highlight of PVSCs. Metal cations are introduced into perovskites to further optimize the quality, and this strategy is showing a vigorous development trend. Here, the progress of research into metal cations for PVSCs is discussed by focusing on the position of the cations in perovskites, the modulation of the film quality, and the influence on the photovoltaic performance. Metal cations are considered in the order of alkali cations, alkaline earth cations, then metal cations in the ds and d regions, and ultimately trivalent cations (p‐ and f‐block metal cations) according to the periodic table of elements. Finally, this work is summarized and some relevant issues are discussed.     

Lithium Isotope Separation by Displacement Chromatography Using Cryptand Resin

This paper summarizes results of sensitivity analysis of a generic geologic disposal system for HLW, using a GSRW code and an automated sensitivity analysis methodology based on the Differential Algebra. The results of sensitivity analyses indicate that parameters related to a homogeneous rock surrounding a disposal facility have higher sensitivities to the performance measure analyzed here than those of a fractured zone and engineered barriers.

This methodology permits sensitivity analyses of a single parameter with changing values of other parameters simultaneously, and thus gives quantitative information on the interrelation- ship between the parameters: the parameters for engineered barriers are generally insensitive to the output, while they are somewhat sensitive to the output only in a case of the low solubility condition. The methodology also provides technical Information which might be basis for the optimization of design of the disposal facility.     

Transfer of Monovalent and Divalent Cations in Salt Solutions by Electrodialysis

Abstract

The selectivity mechanism of transport of Na⁺, Ca²⁺ and Mg²⁺ through commercial monovalent‐cation permselective membranes is investigated in batch electrodialysis experiments with synthetic salt solutions containing monovalent and divalent cations. The role of hydration energy, steric effect, kinetic effect as well as effects of permselectivity of cation exchange membrane has been elucidated with electrodialysis of single solutions (NaCl, CaCl₂, MgCl₂). The mechanism of interferences is investigated in (Na⁺/Ca²⁺, Na⁺/Mg²⁺, Ca²⁺/Mg²⁺ and Na⁺/Ca²⁺/Mg²⁺) mixtures.     

The removal of toxic heavy metal cations by polysulfonebenzylthiourea reactive hollow fiber ultrafiltration membranes

The hollow fiber asymmetric matrix membranes were prepared with phase inversion by utilization of the chloromethyl polysulfone/polyethylene glycol/DMAC casting solution and chloromethyl polysulfone as membrane materials. The effects of composition of spinning casting solution and process parameters of dry–wet spinning on the structure of hollow fiber matrix membrane were investigated. Through the reaction between matrix membrane and thiourea, the highly qualified polysulfonebenzylthiourea reactive hollow fiber ultrafiltration membranes were able to afford. The adsorption isotherms of the polysulfonebenzylthiourea hollow fiber membrane for Cd²⁺ and Zn²⁺ were determined and the effects of mobile phase conditions and the operating parameters on removal performance of the polysulfonebenzylthiourea hollow fiber membrane for Cd²⁺ and Zn²⁺ were also investigated. The experimental results showed that adsorption isotherms of Cd²⁺ and Zn²⁺ could be described by the Langmuir isotherm, the polysulfonebenzylthiourea hollow fiber membrane could be operated at high feed flow rate, and a large‐scale removal of Cd²⁺ and Zn²⁺ could be realized. According to required recovery of Cd²⁺ and Zn²⁺ and the saturation degree of polysulfonebenzylthiourea hollow fiber membrane, the optimum loading amount of Cd²⁺ and Zn²⁺ should be selected in the actual removal of Cd²⁺ and Zn²⁺. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Improvement in the enantioselective hydrogenation of methyl pyruvate over platinum clusters by addition of rare earth cations

The modification of some rare earth metal cations to polymer-stabilized Pt colloidal clusters leads to significant increase in both the ee and the activity in the homogeneous enantioselective hydrogenation of methyl pyruvate to (R)-(+)-methyl lactate. Compared to ee (72.5%) in the absence of rare earth cations, the highest ee (88.0%) in ethanol solvent is obtained by adding a suitable amount of Yb³+ into the Pt colloidal cluster catalyst. The modification effect of rare earth cations is also effective in other alcohol and water solvents.     

High-Voltage Aqueous Na-Ion Battery Enabled by Inert-Cation-Assisted Water-in-Salt Electrolyte

Water-in-salt (WiS) electrolytes provide a new pathway to widen the electrochemical window of aqueous electrolytes. However, their formulation strongly depends on the solubility of the chosen salts, imposing a stringent restriction on the number of possible WiS systems. This issue becomes more severe for aqueous Na-ion batteries (ANIBs) owing to the relatively lower solubility of sodium salts compared to its alkaline cousins (Li, K, and Cs). A new class of the inert-cation-assisted WiS (IC-WiS) electrolytes containing the tetraethylammonium (TEA⁺) inert cation is reported. The Na IC-WiS electrolyte at a superhigh concentration of 31 mol kg^–1 exhibits a wide electrochemical window of 3.3 V, suppresses transition metal dissolution from the cathode, and ensures singular intercalation of Na into both cathode and anode electrodes during cycling, which is often problematic in mixed alkali cation systems such as K–Na and Li–Na. Owing to these unique advantages of the IC-WiS electrolyte, the NaTiOPO₄ anode and Prussian blue analog Na_1.88Mn[Fe(CN)₆]_0.97·1.35H₂O cathode can be coupled to construct a full ANIB, delivering an average voltage of 1.74 V and a high energy density of 71 Wh kg⁻¹ with a capacity retention of 90% after 200 cycles at 0.25C and of 76% over 800 cycles at 1C.     

Fe~(3+)/Ti~(4+)赋存状态对钛酸铝/莫来石复合材料结构的影响

借助XRD、SEM和能谱分析仪等手段,研究了1 600℃煅烧中低品位矾土制备的钛酸铝/莫来石(Al_2TiO_5ss/3Al_2O_3·2SiO_2ss)复合材料经1 200℃保温12h后结构的稳定性。结果表明:高温煅烧中低品位矾土后,其合成材料的结晶物相组成为3Al_2O_3·2SiO_2ss、Al_2TiO_5ss和少量残存的方石英;Fe~(3+)或Ti~(4+)离子以不同形态赋存于结晶相(3Al_2O_3·2SiO_2ss和Al_2TiO_5ss)和非晶相。含Fe~(3+)/Ti~(4+)离子的3Al_2O_3·2SiO_2ss将Al_2TiO_5ss结晶相分割,使其蜷缩其间,并抑制Al_2TiO_5ss的分解;高温下,二者因组成元素相近而致使晶界融合,进而共同构建了体系牢固的致密骨架结构。由3Al_2O_3·2SiO_2ss和Al_2TiO_5ss等高温物相构成的致密结构将非晶相挤压于空隙结构的3Al_2O_3·2SiO_2ss晶间,避免了低熔点相富集带来的不利影响,进而赋予该Al_2TiO_5ss/3Al_2O_3·2SiO_2ss复合材料良好的结构稳定性。     

镧系阳离子修饰SO42-/TiO2-MoO3固体酸催化合成邻苯二甲酸二辛酯

以镧系金属阳离子La3+、Ce3+和Sm3+修饰SO2-4/TiO2-MoO3为催化剂催化合成邻苯二甲酸二辛酯(DOP)。催化剂通过XRD、氮气吸附脱附、吸附吡啶的傅里叶变换红外光谱等方法进行表征,DOP通过红外光谱进行表征。固体酸合成DOP的产率大小顺序为:SO2-4/TiO2-MoO3-Ce3+>SO2-4/TiO2-MoO3-Sm3+>SO2-4/TiO2-MoO3-La3+>SO2-4/TiO2-MoO3。经过修饰后的固体酸与SO2-4/TiO2-MoO3相比较具有更好的催化效果。考察了醇酐比、催化剂用量对催化合成DOP的影响。结果表明,合成DOP的最佳条件为醇酐比2.2∶1、催化剂的质量分数为1.5%,其酯化率为92.4%。催化剂重复使用3次之后,仍然有很高的催化效果,达到77.4%。