Synergetic Coupling of Redox-Active Sites on Organic Electrode Material for Robust and High-Performance Sodium-Ion Storage

Organic electrode materials (OEMs), valued for their sustainability and structural tunability, have been attracting increasing attention for wide application in sodium-ion batteries (SIBs) and other rechargeable batteries. However, most OEMs are plagued with insufficient specific capacity or poor cycling stability. Therefore, it′s imperative to enhance their specific capacity and cycling stability through molecular design. Herein, we designed and synthesized a heteroaromatic molecule 2,3,8,9,14,15-hexanol hexaazatrinaphthalene (HATN-6OH) by the synergetic coupling of catechol (the precursor of ortho-quinone)/ortho-quinone functional groups and HATN conjugated core structures. The abundance of catechol/ortho-quinone and imine redox-active moieties delivers a high specific capacity of nine-electron transfer for SIBs. Most notably, the π–π interactions and intermolecular hydrogen bond forces among HATN-6OH molecules secure the stable long-term cycling performance of SIBs. Consequently, the as-prepared HATN-6OH electrode exhibited a high specific capacity (554 mAh g⁻¹ at 0.1 A g⁻¹), excellent rate capability (202 mAh g⁻¹ at 10 A g⁻¹), and stable long-term cycling performance (73 % after 3000 cycles at 10 A g⁻¹) in SIBs. Additionally, the nine-electron transfer mechanism is confirmed by systematic density functional theory (DFT) calculation, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and Raman analysis. The achievement of the synergetic coupling of the redox-active sites on OEMs could be an important key to the enhancement of SIBs and other metal-ion batteries.     

Mobility-Modulated Sequential Dissociation Analysis Enables Structural Lipidomics in Mass Spectrometry Imaging

Spatial lipidomics based on mass spectrometry imaging (MSI) is a powerful tool for fundamental biology studies and biomarker discovery. But the structure-resolving capability of MSI is limited because of the lack of multiplexed tandem mass spectrometry (MS/MS) method, primarily due to the small sample amount available from each pixel and the poor ion usage in MS/MS analysis. Here, we report a mobility-modulated sequential dissociation (MMSD) strategy for multiplex MS/MS imaging of distinct lipids from biological tissues. With ion mobility-enabled data-independent acquisition and automated spectrum deconvolution, MS/MS spectra of a large number of lipid species from each tissue pixel are acquired, at no expense of imaging speed. MMSD imaging is highlighted by MS/MS imaging of 24 structurally distinct lipids in the mouse brain and the revealing of the correlation of a structurally distinct phosphatidylethanolamine isomer (PE 18 : 1_18 : 1) from a human hepatocellular carcinoma (HCC) tissue. Mapping of structurally distinct lipid isomers is now enabled and spatial lipidomics becomes feasible for MSI.     

A modified QuEChERS-gas chromatography-mass spectrometry method for the determination of pesticide residues in Lonicera japonicae FlosEI北大核心CSCD

A modified QuEChERS-gas chromatography-mass spectrometry method using multi-walled carbon nanotubes （MWCNTs）as adsorbent was established for the determination of 72 pesticide residues in Lonicera japonicae Flos. The sample was extracted with Association of Official Agricultural Chemists （AOAC）extracting package,purified with MWCNTs-modified purification tube,analyzed with dynamic multiple reaction monitoring mode,and quantified with external standard method of matrix-matched standard curve. The 72 pesticides showed good linearities in the corresponding concentration ranges with correlation coefficients greater than 0.9936. The limits of detection were 0.001-0.178 μµg/kg,and the limits of quantitation were 0.002-0.593 μµg/kg. The average recoveries for four spiked levels ranged from 60.1% to 118.0%,with the relative standard deviations of 2.2%-17%. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

过渡金属原子X (X=Mn、Fe、Co)掺杂单层Janus WSSe的第一性原理研究

二维Janus WSSe作为一种新兴的过渡金属硫族化合物(TMDs)材料,由于其打破了面外镜像对称性,且具有内在垂直压电和强Rashba自旋轨道耦合效应等丰富的物理特性,在自旋电子器件中具有巨大的应用潜力。本文基于密度泛函理论的第一性原理平面波赝势方法计算了过渡金属原子X(X=Mn、Fe、Co)掺杂单层Janus WSSe的电子结构、磁性和光学性质。结果表明：在Chalcogen-rich(硫族元素为多数元素)条件下的掺杂比在W-rich(钨元素为多数元素)条件下的掺杂展现出更高的稳定性,且掺杂后所有体系均表现出磁性。值得一提的是,对该体系进行Mn掺杂后,自旋向上通道出现杂质能级,WSSe由原来的非磁性半导体转变成磁矩为1.043μ_B的铁磁性半金属。而Fe、Co的掺杂使得自旋向上通道和自旋向下通道均出现杂质能级,呈现出磁矩分别为1.584μ_B、2.739μ_B的金属性。此外,掺杂体系的静态介电常数都显著增加,极化程度增强,且介电函数虚部和光吸收峰都发生了红移,说明掺杂有利于对可见光的吸收。     

纳米CoSe修饰氮掺杂多孔碳的可控制备及其锂硫电池多硫化物的催化转化效应

锂硫电池中较差的循环稳定性和倍率性能是实现锂硫电池商业化的技术障碍,其主要原因之一是多硫化物在硫电极内的电化学转化速率较为缓慢。为此,我们以ZIF-9为前驱体,采用先碳化,再酸化刻蚀,最后硒化的方法合成了含少量催化剂的CoSe修饰氮掺杂多孔碳(CoSe/NC)电极材料,以期提高硫电极内多硫化物的电化学转化动力学性能,并通过流动液相三电极体系对该材料进行电化学动力学表征。结果显示,相较于对比材料,CoSe/NC能够加快多硫化物的氧化还原反应速率,在0.2mA·cm-2电流密度下,多硫化物氧化还原反应在CoSe/NC电极上有最小的反应过电位;同时,在0.1 V过电位下,各氧化还原反应也有最大的响应电流。因此,将CoSe/NC作为硫宿主材料组装电池展现了优异的电化学性能：在1C(1C=1 675 mA·g^-1)下初始放电比容量为1 068 mAh·g^-1,经过500次循环后,可逆容量仍保持在693 mAh·g^-1。另外,在3C的高电流密度下,放电比容量可高达819 mAh·g-1。     

捕捉环加成反应中的有机亚铜中间体构筑氮杂环化合物研究进展

铜(I)盐催化的环加成反应,如叠氮-炔[3+2]环加成(Cu AAC)、不饱和化合物与异氰基化合物的[3+2]环加成、硝酮-炔的环加成(Kinugasa反应)是构建多类氮杂环的高效合成方法,被广泛应用于有机合成的各个领域.近年来,针对几类环加成反应中产生的有机亚铜中间体的多样性转化吸引了国内外很多课题组的注意,基于对这些环加成反应中有机亚铜中间体的捕捉,多类串联及多组分反应得以发展,从而成功实现了一系列多取代杂环或稠环结构的高效构建.本综述总结了这一领域的研究进展,按照所经历的有机亚铜中间体的类型进行分类,包括:(1)Cu AAC反应中产生的三氮唑亚铜中间体;(2)炔烃与异氰化合物[3+2]环加成反应中产生的2H-吡咯基亚铜中间体;(3) Kinugasa反应中产生的烯醇亚铜中间体.期望此综述能够有助于研究者了解有机亚铜中间体捕捉策略的发展、应用现状及不足之处,进一步推动铜催化转化的发展.     

交互模式-电感耦合等离子体质谱(ICP-MS)法测定生态地球化学植物样品中7种金属元素

植物样品中各元素的含量,是评价土壤质量及健康的重要指标。为满足测定大批量生态地球化学植物样品中多金属元素分析要求,建立了交互模式-电感耦合等离子体质谱(ICP-MS)法测定植物样品中7种痕量金属元素的定量分析方法。讨论了ICP-MS的STD、KED(He)、交互模式3种方法测定植物样品中7种金属元素结果。结果表明,利用工作曲线法配制Hg标准溶液,更改⁸²Se在线校正方程系数为1.83,在ICP-MS的交互模式下测定植物样品中⁸²Se、⁶³Cu、⁶⁰Ni、⁶⁶Zn、¹¹¹Cd、⁷⁵As、²⁰²Hg可以得到准确可靠的结果,克服了植物样品中Se和Hg元素测定的难题。基于所建方法各元素校准曲线系数>0.999,方法检出限为0.000 4～0.08 mg/kg,加标回收率在96.2%～107%,测定GBW10010a(大米)、GBW10012(玉米)、GBW10021(豆角)3种标准物质,结果均在参考值范围内,相对标...     

酸溶-电感耦合等离子体发射光谱法测定白云石和菱镁石中主次元素

利用电感耦合等离子体原子发射光谱仪( ICP-AES)建立白云石和菱镁石中铝、钙、铁、镁、锰、磷、硅、锶的测定方法。研究了酸体系、温度及消解方式对试样消解的影响,结果表明,使用5 mL盐酸和硝酸混合酸(1：3)-0.75 mL氢氟酸-5 mL水以密闭消解的方式在150 ℃下消解白云石和菱镁石30min,并以2mL饱和硼酸络合多余的氢氟酸,可以得到澄清消解液。通过白云石和菱镁石中铝、钙、铁、镁、锰、磷、硅、锶的谱线干扰情况,选择Al 308.215 nm、Ca 318.127 nm、Fe 261.187 nm、Mg 277.983 nm、Mn 257.61 nm、P 213.618 nm、Si 251.611 nm、Sr 421.552 nm作为分析线,各元素的校准曲线在线性范围内线性关系良好,相关系数均不小于0.999。按照实验方法测定白云石和菱镁石标准物质,各元素结果的相对标准偏差 (RSD, n=6)为0.89~3.19%,测定值与认定值无显著性差异。本方法有效解决了白云石和菱镁石快速有效溶解及准确测定问题。     

Chemical modification of L-asparaginase with N, O-carboxymethyl chitosan and its effects on plasma half-life and other properties

E.coli L-asparaginase,an antitumor enzyme,was chemically modified with N,O-carboxymethyl chitosan to lower its artigenicity and increase its plasma half-life.The results showed that the modified L-asparaginase has almost the same apparent Km value as that of native enzyme.The modified L-asparaginase also showed a higher protease stability against trypsin and a-chymotrypsin.After being modified,the enzyme exhibited the complete loss of antigenicity towards antiasparaginase serum.In addition,the higher the molecular weight of modifying reagents,the better the effects on reduction of antigenicity.When tested in vivo,the plasma half-life of the modified enzyme (t1/2=40 h) was over 33 times longer than that of the native enzyme (t1/2=1.2 h).     

O／W微乳液中聚吡咯超微粒子的制备

选择合适的ＳＤＢＳ／吡咯／Ｈ２Ｏ三组分Ｏ／Ｗ微乳液与吡咯单体共存的两相体系，以单体相为单体源，在Ｏ／Ｗ三组分微乳液中进行了吡咯聚合，所得聚吡咯粒子大小仅为２～３ｎｍ，分布较均匀，且具有较好的导电性能．