含柔性侧链季鏻阳离子结构的聚芳醚腈阴离子交换膜（英文）

为有效改善聚合物阴离子交换膜材料(AEMs)的性能,本研究在综合考虑聚合物结构、离子官能团种类及其链接方式对AEMs影响的基础上,设计制备了一系列含有柔性侧链型季鏻阳离子结构的新型聚芳醚腈(PAEN-TPP-x)阴离子交换膜.分别对所制聚芳醚腈阴离子交换膜的合成方法、结构和离子交换容量、吸水率、溶胀率、氢氧化物电导率及碱稳定性进行了系统研究,并与一些其他已报道的AEMs进行了比较研究,以进一步探索其结构与性能之间的关系.研究发现所制备的含有柔性侧链型季鏻阳离子结构的聚芳醚腈阴离子交换膜具有良好的综合性能.在60℃下,它们的吸水率、溶胀率和离子传导率分别为11.6%–22.7%,4.4%–7.8%和28.6–45.8 mS cm^-1.与此同时,该类AEMs还表现出良好的碱性稳定性,其中代表性样品PAEN-TPP-0.35在2 mol L^-1NaOH溶液中、60和90℃下浸泡480 h后的OH-传导率分别保持在其初始值的82.1%和80.6%.本研究可为高性能聚合物阴离子交换膜材料的设计制备和改性提供新的思路和方法.     

Highly Efficient and Stable Solar Cells Based on Crystalline Oriented 2D/3D Hybrid Perovskite

Highly efficient and stable 2D/3D hybrid perovskite solar cells using 2‐thiophenemethylammonium (ThMA) as the spacer cation are successfully demonstrated. It is found that the incorporation of ThMA spacer cation into 3D perovskite, which forms a 2D/3D hybrid structure, can effectively induce the crystalline growth and orientation, passivate the trap states, and hinder the ion motion, resulting in improved carrier lifetime and reduced recombination losses. The optimized device exhibits a power conversion efficiency (PCE) of 21.49%, combined with a high V_OC of 1.16 V and a notable fill factor (FF) of 81%. More importantly, an encapsulated 2D/3D hybrid perovskite device sustains ≈99% of its initial PCE after 1680 h in the ambient atmosphere, whereas the control 3D perovskite device drops to ≈80% of the original performance. Importantly, the device stability under continuous light soaking (100 mW cm^?2) is enhanced significantly for 2D/3D perovskite device in comparison with that of the control device. These results reveal excellent photovoltaic properties and intrinsic stabilities of the 2D/3D hybrid perovskites using ThMA as the spacer cation.     

Na‐Cation‐Assisted Exfoliation of MX2 (M = Mo,W; X = S,Se) Nanosheets in an Aqueous Medium with the Aid of a Polymeric Surfactant for Flexible Polymer‐Nanocomposite Memory Applications

2D nanosheets of transition metal dichalcogenides (TMDCs) have been attracting attention due to their sizable band gap. Facile and effective Na‐cation‐assisted exfoliation of TMDC (MX₂, M = Mo, W; X = S, Se) nanosheets in an aqueous medium and their application as a composite filler in a polyvinyl alcohol (PVA) matrix are explored in this work. The presence of Na cations is highly beneficial for exfoliating defect‐free and few‐layer MX₂ nanosheets in water in the presence of small‐sized micelles of polymeric surfactant, and significantly elevates the exfoliation yield by more than one order of magnitude compared to a conventional surfactant‐assisted exfoliation. The strategy suggested in this work is very advantageous compared to both Li cation intercalation in organic solvents and conventional low‐yield surfactant‐assisted exfoliations. As an application of the exfoliated nanosheets, the fabrication of memory devices with the configuration of Ga‐doped ZnO/MX₂–PVA/Ag is demonstrated, and they exhibit bistable and write‐once‐read‐many‐times resistive switching behavior with a high ON/OFF current ratio of 3 × 10³ at ?1.0 V (for WS₂) and 2.0 V (for MoS₂). Furthermore, MX₂–PVA nanocomposite fibrous films and mats are successfully fabricated using an electrospinning technique, which can expand the use of TMDC nanofillers in applications involving highly flexible polymer‐based MX₂ composites.     

Effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋） on the electrochemical synthesis of polyaniline in nitric acid electrolyte

The effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋）on the electrochemical synthesis of polyaniline were carfled out under cyclovoltammetric conditions using nitrates of Li^＋, Na^＋, K^＋, and Cs^＋ as the supporting electrolytes. The results show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreases from the fast scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration of alkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also depends on the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the effect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is further lower than that of W. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electrosynthesis. Therefore, this is exactly what SEM images show： a relatively rough fibrous structure in the case of Pani-H^＋ suggesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M^＋.     

Ions in space

We review the detection history, observation, distribution, and reactivity of molecular ions in extraterrestrial space, with particular (though not exclusive) reference to interstellar monocations. The diversity of interstellar ion chemistry is highlighted with reaction examples, drawn from the authors' own laboratories and elsewhere, and attempt to provide an overview of this broad and increasingly divergent field. Emphasis is given to the role of ions in the synthesis of molecules, including their ability to catalyze the transformation of neutral molecules.     

Metal Halide Perovskite Surfaces with Mixed A-Site Cations: Atomic Structure and Device Stability

Mixing cations in the perovskite structure has been shown to improve optoelectronic device performance and stability. In particular, Cs_xMA_1-xPbBr₃ (MA = CH₃NH₃) has been used to build high-efficiency light-emitting diodes. Despite those advantages, little is known about the exact location of the cations in the mixed perovskite film, and how cation distribution affects device properties and stability. By using scanning tunneling microscopy , the exact atomic structure of the mixed cation Cs_xMA_1-xPbBr₃ perovskite interface is revealed. In addition, X-ray photoelectron spectroscopy, ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy are used to study the stability and electronic properties of the Cs_xMA_1-xPbBr₃ perovskite film. Partial substitution of MA⁺ by Cs⁺ induces a modification of the perovskite surface structure, leading to improved device stability is shown. These results provide a better understanding of the key parameters involved in the stability of mixed cation perovskite solar cells.     

使用Mg^2＋取代Ca^2＋对大豆球蛋白及伊伴球蛋白进行分级与表征

使用一种简单的两步沉淀方法研究了Mg^2＋和Ca^2＋对大豆球蛋白及β-伴球蛋白级分分级的影响,并对所得产品的某些理化性质进行了表征．结果表明,加入5mM Mg^2＋是优化的条件;使用5mM Mg^2＋得到的大豆球蛋白和β-伴球蛋白级分的植酸含量分别是0．4％和1．3％;加入5mM Ca^2＋却使球蛋白级分植酸含量较高,为1．3％;植酸-镁复合物要比植酸-钙复合物的溶解性要高许多;使用Mg^2＋所获得的β-伴球蛋白级分的热稳定性获得了提高,使用Mg^2＋得到的富含球蛋白的级分的可溶性在pH〈4．5下显著高于使用Ca^2＋得到的相应级分．排阻色谱（SEC-HPLC）实验结果表明高植酸含量会引起球蛋白的聚合．     

FTIR analyses of water in MX-80 bentonite compacted from high salinary salt solution systems

The effect of the exchangeable cations on the infrared (IR) spectra of water in MX-80 bentonite compacted from high salinary salt solution systems was studied using self-supporting film and attenuated total reflection (ATR) techniques. Na-bentonite MX-80 was saturated with homo-cationic (NaCl, KCl, CaCl₂ or MgCl₂) or hetero-cationic (mixtures of Na–, K–, Ca– and Mg–chlorides) solutions. The specimens for IR spectroscopy were prepared as self-supporting films (ssf) or compacted pastes. Differences in the wavenumbers and intensities of the structural OH group vibrations in relation to the type of the interlayer cation were found in the spectra of heated ssf. The most pronounced changes were observed for Mg-ssf, while only negligible changes occurred for K-ssf. The absorptions of water in heated Na- and K-ssf showed displacement of the stretching and bending bands to higher and lower wavenumbers, respectively, which indicates decreasing strength of H-bonding between water molecules. In contrast, for Mg-ssf the position of the stretching band of water substantially decreased on heating up to 90 °C followed by an increase upon further heating above 100 °C. The origin of these differences was discussed in terms of variations in the polarising ability of the interlayer cations influencing their hydration number. The ATR spectra of homo-cationic clay-pastes showed that the interlayer cations modify both the position and the intensity of the complex water band near 3400 cm⁻¹. The position decrease and the intensity increase followed the same order: K⁺, Na⁺, Ca²⁺, Mg²⁺. Good correlation between water band position and polarising power of the cations confirmed their influence on the strength of hydrogen bonds between water molecules. Similarly, a systematic shift of the H₂O-stretching band to lower frequencies with the increasing Mg²⁺ content in the samples was observed in the spectra of clay-pastes saturated with hetero-cationic chloride solutions. The intensity of the stretching band of water of both homo- and hetero-cationic pastes correlated very well with the water content obtained gravimetrically.     

The interaction of butenes with Cu ions in CuMCM-41 studied by IR spectroscopy

As CuMCM-41 was found to be active in skeletal isomerisation of n-butenes, we followed by IR spectroscopy the interaction of but-1-ene, cis-but-2-ene, and trans-but-2-ene with Cu⁺ sites in CuMCM-41. It has been revealed that Cu⁺ activated strongly CC bond, what resulted in a frequency shift of CC stretching band by about 100 cm⁻¹. Moreover, the vibration of CH bonds in CH₂ and CH groups neighbouring to the double bonds was also perturbed. We suppose that the activation of CC bond is a result of π-back donation of d electrons of Cu⁺ to π^* antibonding orbitals of butenes. IR results evidenced also the heterogeneity of Cu⁺ sites in CuMCM-41 and the presence of Cu⁺ sites of various electron donor properties. But-1-ene molecules bonded to Cu⁺ ions are less prone to accept protons from Brønsted acid sites than molecules bonded by hydrogen bonding to non-acidic SiOH groups, even though they are more negative than free or physisorbed molecules. The IR studies of coadsorption of CO and but-1-ene suggest that the interaction of CO with Cu⁺ is much weaker if but-1-ene is present, than without butene.     

Electroless immobilization and electrochemical characteristics of nickel hexacyanoruthenate film at an aluminum substrate

The surface of an aluminum (Al) electrode was modified with a thin film of nickel hexacyanoruthenate (NiHCR) as a novel electrode material. The modification procedure of Al surface, includes two consecutive procedures: (i) the electroless deposition of metallic nickel on the Al electrode surface from NiCl₂ solution, and (ii) the chemical transformation of deposited nickel to nickel hexacyanoruthenate films in solution of 20 mM K₃[Ru(CN)₆] + 0.5 M KNO₃. Cyclic voltammogram of the modified Al electrode showed a well-defined redox reaction due to [Ni^IIRu^III/II(CN)₆]^1−/2− system. The effects of different supporting electrolytes and solution pH were studied on the electrochemical characteristics of the modified electrode. The diffusion coefficients of K⁺ and Na⁺ cations in the film (D), the transfer coefficient (α), and the charge transfer rate constant at the modifying film/electrode interface (k_s), were calculated in the presence of both K⁺ and Na⁺ cations. The stability of the modified electrode was investigated under various experimental conditions.