様々な形態を有するシアン架橋型配位高分子結晶の創製

早大学位記番号:新8181早稲田大

Two-dimensional cyano-bridged coordination polymer of Mn(H2O)(2)[Ni(CN)(4)]: structural analysis and proton conductivity measurements upon dehydration and rehydration

Two-dimensional (2D) materials are widely investigated as electronic or catalytic materials as well as being conventionally used as adsorbents for accommodating guest molecules in the interlayer spaces. 2D coordination polymers have flexible structures, which are transformed even by a weak external stimulus such as a humidity change. Here we report a structural analysis and proton conductivity measurements of a 2D cyano-bridged coordination polymer of the Mn[Ni(CN)(4)] system upon dehydration and rehydration. The structure of the sample at high humidity was determined by single-crystal diffraction, while the structure at low humidity was solved by Rietveld analysis of synchrotron powder diffraction data. At high humidity, the material contains coordinated and non-coordinated water molecules as [Mn(H2O)(2)Ni(CN)(4)]3H(2)O. These water molecules were further analyzed by TG-DTA and classified into three types: (i) two coordinated molecules, (ii) two weakly adsorbed non-coordinated molecules and (iii) a strongly adsorbed non-coordinated molecule. These water molecules play a key role in crystal structure transformation upon dehydration/hydration, where the two-dimensional coordination network is retained but the curvature changes by tilting of MnO6 octahedra owing to the change in hydrogen bonds between the water molecules. Because the water molecules form hydrogen bonding networks, proton conductivity was expected. Thus, we investigated the proton conductivity using the single-crystal AC impedance method and found that the crystals were insulating. This in turn suggests that the water molecules in the interlayer spaces do not dissociate into protons mostly, and the spaces are non-ionic

Confined synthesis of coordination frameworks inside double-network hydrogel for fabricating hydrogel-based water pipes with high adsorption capacity for cesium ions

Hydrogel-based water pipes which can capture ionic contaminants are a promising solution for achieving efficient water treatment. However, the fabrication of such unique water pipes as an ion-harvester remains a challenge. In this work, we have fabricated this kind of water pipe through the confined synthesis of coordination frameworks inside a double-network PAAm/PAMPS hydrogel. The hydrogel could trigger the partial decomposition and reduction of K-3[Fe(CN)(6)] upon heating. The released Fe3+/Fe2+ ions could react with the [Fe(CN)(6)](4)(-)/[Fe(CN)(6)](3)(-), finally producing Prussian Blue coordination frameworks inside the hydrogel. The resulting composite exhibited a high capacity for Cs+ ions (397 mg g(-1) in 10 minutes) by taking the coupling effect between the cation-selective hydrogel and the coordination frameworks. By shaping this composite into water pipes, Cs+ ions present in the contaminated water could be captured by the pipe wall. The proposed strategy will be useful, providing a potential method for fast treatment of aqueous nuclear waste

Progress in Solid Polymer Electrolytes for Lithium-Ion Batteries and Beyond

Solid-state polymer electrolytes (SPEs) for high electrochemical performance lithium-ion batteries have received considerable attention due to their unique characteristics; they are not prone to leakage, and they exhibit low flammability, excellent processability, good flexibility, high safety levels, and superior thermal stability. However, current SPEs are far from commercialization, mainly due to the low ionic conductivity, low Li+ transference number (tLi+), poor electrode/electrolyte interface contact, narrow electrochemical oxidation window, and poor long-term stability of Li metal. Recent work on improving electrochemical performance and these aspects of SPEs are summarized systematically here with a particular focus on the underlying mechanisms, and the improvement strategies are also proposed. This review could lead to a deeper consideration of the issues and solutions affecting the application of SPEs and pave a new pathway to safe, high-performance lithium-ion batteries.</p

0D–1D hybrid nanoarchitectonics: tailored design of FeCo@N–C yolk–shell nanoreactors with dual sites for excellent Fenton-like catalysis

Novel 0D–1D hybrid nanoarchitectonics consisting of FeCo@N–C yolk–shell nanoreactors are developed for Fenton-like reaction. With the multilevel advantages of this design, FeCo@N–C nano-necklaces exhibit excellent performance for BPA removal.</jats:p

Ultra-durable, multi-template molecularly imprinted polymers for ultrasensitive monitoring and multicomponent quantification of trace sulfa antibiotics

Molecularly-imprinted polymers have been used for the selective and ultrasensitive monitoring of trace sulfa antibiotics avoiding sample matrix interference effects and leading to improved reusability of the relevant materials.</p

Dual-textured Prussian Blue nanocubes as sodium ion storage materials

Sodium ion batteries are being highlighted as a promising energy storage system to resolve the critical issues associated with lithium ion battery usage due to a limited quantity of lithium resources on the earth. Although recent advances in sodium ion battery technology have been remarkable, the reversible capacities and cyclic performance of sodium ion batteries should be further advanced prior to their successful implementation. Herein, we demonstrate dual-textured Prussian blue nanocubes prepared via simple acid etching as a reliable sodium storage material. Taking advantage of their hybrid microstructure composed of porous and non-porous domains, dual-textured Prussian blue nanocubes exhibit high reversible capacities, good rate capabilities, and stable cyclic performance. Moreover, the nanocubes exhibit excellent dimensional stability even after 100 cycles, offering new opportunities for the development of robust and high-performance sodium rechargeable batteries. (C) 2017 Published by Elsevier Ltd

Electrochemical preparation of nano/micron structure transition metal-based catalysts for the oxygen evolution reaction

This is a comprehensive review of the electrochemical synthesis of nano/microstructure transition metal-based materials for oxygen evolution reaction from the aspects of ‘Fundamentals, Structural design and Classification’.</jats:p