Electrodeposition and Electrochemical Properties of Ternary Sn-Co-Zn Alloy Electrodes as Anodes for Lithium-Ion Batteries

Corresponding author. Email: [email protected]; Tel: +86-592-5343629.[中文文摘]运用电沉积技术制备出Sn-Co-Zn合金电极材料.采用X射线衍射(XRD)和扫描电子显微镜(SEM)分析了该合金材料的相结构和表面形貌.通过循环伏安和电位阶跃实验研究了Sn-Co-Zn合金的电沉积机理,实验表明,Sn-Co-Zn合金电沉积按扩散控制连续成核和三维生长方式进行.XRD结果表明,该合金由CoSn3、Co3Sn2和Zn组成.电化学性能测试表明:Sn-Co-Zn合金电极首次放电(脱锂)容量达751mAh·g-1,首次循环的库仑效率为88%;30周循环之后放电容量为510mAh·g-1.该Sn-Co-Zn合金电极良好的电化学储锂性能可能归因于材料的多相结构.[英文文摘]A ternary Sn-Co-Zn alloy film was successfully prepared by electrodepositi on copper foil. Electrochemical deposition of the Sn-Co-Zn alloy was studied by cyclic voltammetry (CV) and chronoamperometry (CA). The structure and electrochemical performance of the electroplated Sn-Co-Zn alloy electrodes were also investigated in detail. The CV and CA results revealed that the initial deposition kinetics of the Sn-Co-Zn alloy corresponds to a model that includes a three-dimensional progressive nucleation and diffusion controlled growth. XRD results showed that the electrodeposited Sn-Co-Zn alloy consists of CoSn3, Co3Sn2, and Zn phase. Electrochemical tests indicated that at the first cycle, the discharge capacity (desertion) and columbic efficiency are measured 751 mAh·g-1 and 88%, respectively, at the 30th cycle, the Sn-Co-Zn alloy electrodes still delivered a discharge capacity of 510 mAh·g-1. The good lithium storage performance of the Sn-Co-Zn electrode is ascribed to multi-phase structure of the electrode.国家自然科学基金(20773102);国家基础研究重大项目计划(973)(2009CB220102)资

高分辨率核磁共振纯化学位移谱新方法及其应用

核磁共振(Nuclear Magnetic Resonance,NMR)以无辐射、非入侵、高分辨率及信息丰富等特点被广泛应用在化学、生物、医药、材料等领域.纯化学位移技术,因其能大幅提高NMR重叠谱图分辨率的优良特性,近年来逐渐成为NMR领域的研究热点.本文结合作者所在团队在纯化学位移新技术及其应用研究的基础上,评述了纯化学位移技术的发展现状,及其机遇与挑战.国家自然科学基金大科学装置联合基金重点项目(U1632274

High-index-faceted platinum nanoparticles: insights into structural and thermal stabilities and shape evolution from atomistic simulations

National Natural Science Foundation of China [51271156, 11204252]; Natural Science Foundation of Fujian Province of China [2013J06002]; Specialized Research Fund for the Doctoral Program of Higher Education of China [20130121110012]High-index-faceted Pt nanoparticles exhibit exceptional electrocatalytic activity owing to the high density of low coordinated sites on their surface, and thus have attracted extensive studies over the past few years. In this study, we have employed atomistic simulations to systematically investigate the structural and thermal stabilities and shape evolution of Pt nanoparticles with different high-index facets, that is, tetrahexahedra enclosed by {hk0} facets, trapezohedra by {hkk} ones, and trisoctahedra by {hhk} ones. The results show that {221} faceted trisoctahedral nanoparticles display the best structural and thermal stabilities while {410} faceted tetrahexahedral ones display the worst. The shape stability of these nanoparticles generally decreases in the order from trapezohedron to tetrahexahedron to trisoctahedron. For the same type of polyhedron, the structural, thermal and shape stabilities of the nanoparticles all decrease according to the order of {2kl}, {3kl} and {4kl} facets. Further analyses have discovered that a large proportion of high-coordinated surface atoms are beneficial for enhancing both the thermal and shape stabilities. This work provides an in-depth understanding of surface structures and thermodynamic evolution of high-index-faceted metallic nanoparticles

Tetrahexahedral Pt-Pd alloy nanocatalysts with high-index facets: An atomistic perspective on thermodynamic and shape stabilities

Metallic nanoparticles with high-index facets exhibit exceptional electrocatalytic activity owing to the high density of low coordination sites at the surface, thus they have attracted intense interest over the past few years. Alloying could further improve their catalytic activity by the synergy effects of high-index facets and electronic structures of components. Using atomistic simulations, we have investigated thermodynamic and shape stabilities of tetrahexahedral Pt-Pd alloy nanoparticles respectively bound by {210} and {310} facets. Energy minimization through Monte Carlo simulations has indicated that the outermost layer is predominated by Pd atoms while Pt atoms preferentially occupy the sub-outermost layer of nanoparticles. Molecular dynamics simulations of the heating process have shown that the {210} faceted nanoparticles possess better thermodynamic and shape stabilities than the {310} faceted ones. The coordination numbers of surface atoms were used to explore the potential origin of the different stabilities. Furthermore, a high Pt ratio will help enhance their stabilities. For both faceted nanoparticles, the melting has homogeneously developed from the surface into the core, and the tetrahexahedra have finally evolved into sphere-like shape prior to the overall melting. These results are helpful for understanding the composition and thermodynamic properties of high-index faceted nanoparticles, and are also of practical importance to the development of alloy nanocatalysts. ? 2014 The Royal Society of Chemistry

Single-crystalline and multiple-twinned gold nanoparticles: an atomistic perspective on structural and thermal stabilities

National Natural Science Foundation of China [51271156, 11204252]; Natural Science Foundation of Fujian Province of China [2013J06002]; Fundamental Research Funds for the Central Universities of China [2012121010]Morphologies of gold nanoparticles play an important role in determining their chemical and physical (catalytic, electronic, optical, etc.) properties. Therefore, a fundamental understanding of the morphological stability is of crucial importance to their applications. In this article, we employed atomistic simulations to systematically investigate the structural and thermal stabilities of gold particles with eight representative nanoshapes, including single-crystalline and multiple-twinned structures. Our investigation has revealed that the truncated octahedron and the octahedron possessed the best structural stability, while the tetrahedron and the icosahedron did the worst. Further analyses have discovered different thermal stabilities and diverse melting behaviors in these particles. Especially, an inhomogeneous melting of the icosahedron was disclosed, and the relevant mechanism was elucidated. This study provides significant insight not only into the experimental preparation of gold nanoparticles but also into the design of gold nanostructures with both high catalytic activity and excellent stability

EFFects of diFFerent phosphorus sources on algal growth and biochemical composition

在实验室培养条件下，用kH2PO4及多种溶解有机磷化合物（dOP）对藻类进行一次性培养，考察藻类对dOP的利用和不同磷源对藻类生长及其生化组成的影响。结果表明：甘油磷酸钠（g·P）、6-磷酸葡萄糖（g·6·P）、蛋黄卵磷脂（lEC）和酵母核糖核酸（rnA）均可被藻类吸收利用，并且培养藻类都生长良好；碱性磷酸酶在大分子dOP（如lEC、rnA）利用过程中起重要作用。不同形态磷才培养藻类的蛋白质、氨基酸合量有一定影响。Under batch culture condition, the eFFects of diFFerent phosphorus sources (phosphate,glycerophosphate, glucose-6-phosphate, lecithins and yeast RNA) on algal growth and biochemical composition are carried out.Results showed that Four algae of this test could uptake DOP compounds used in this experiment and growth curve cultured in DOP compounds is almost conslstent with that in phosphate, alkaline phosphatase plays an important role in the utilization of large molecular DOP compound such as lecithins and RNA- Result also indicates that there is little diFFerence of protein and amino acid between culturing in phosphate and DOP compounds

SECRETION PROCESS OF EXTRACELLULAR POLYMERS IN ACHNANTHES JAVANICA VAR.MEISTER AND THE IMPACT BY HERBICIDE

采用微孔板培养法,研究了爪哇曲壳藻亚缢变种胞外多聚物的分泌过程及除草剂对该过程的影响。结果表明,爪哇曲壳藻亚缢变种胞外多聚物的分泌过程分为4期即单细胞形成及重新定位期、球状体形成期、领形成和柄延伸期及细胞分裂增殖期。除草剂对胞外多聚物分泌的影响与其浓度有关当除草剂浓度为10×10-6时,除草剂对爪哇曲壳藻亚缢变种单细胞的形成和运动没有影响,但胞外多聚物柄的生产受到抑制,柄的长度也明显缩短;随着除草剂浓度的进一步增加,群体细胞不能散开形成单细胞,胞外多聚物的分泌受到完全抑制。本研究结果表明,爪哇曲壳藻亚缢变种胞外多聚物的分泌与细胞运动有关,除草剂可能影响了细胞内有机物质的合成和某些细胞器(如囊泡)的功能,从而抑制了胞外多聚物的分泌。Achnanthes spp. is a prominent member of fouling communities in marine environments,which produces long extracellular polymeric substances(EPSs)-stalks and attaches to the surfaces of various substrates. This study investigated the secretion process by Achnanthes javanica var. Meister isolated from coastal waters of Xiamen,using micro-plate culture method,and the impacts of three herbicides on the secretion process were also investigated. The results showed that the secretion process could be divided into four phases. The first phase is single cell formation and cell reorientation phase,which started after 4—5h of inoculation of cells. Single cell separated from a filamentous colony and moved till a suitable position was found. The second phase is spherical pad formation;the cell motility stopped 2 to 3 h after the cell attached to the bottom. A small globular structure(pad)was produced in one side of the cell surface. The third phase is stalk elongation and collar-shaped structure formation,a highly structured stalk was formed and elongated 10 to 12h after the inoculation. Meanwhile,a collar structure also formed near the valve. The last phase is cell division and multiplication. Cells were multiplied successively and formed a filamentous colony or a stack of cells 12h after the inoculation. The impacts of herbicides on the secretion process depend on herbicide's concentrations. At 10×10 -6 ,the formation of single cell was not affected and majority of cells could move,but the secretion was constrained and the length of the stalk was shortened significantly. 60% of the cells produced extracellular polymers and about 12% of them were with long stalks. Cell division was constrained in some cells. At concentration of 30×10 -6 ,formation of single cell kept going but motility was inhibited in most cells,and the secretion of globular structure(pad)was inhibited in 60% of total cells. Stalks formation and cell division were completely stopped. At higher herbicide concentration of 80×10 -6 ,formation of single cell was ceased and some cells were dead. The results demonstrate that the secretion of EPSs is a fast and essential biological process in A. javanica var. Meister,which depends on cell motility. Some organelles such as vesicles in cytoplasm may involve in EPS biosynthesis. The herbicides inhibit single cell formation and cell motility,influence organelle synthesis and their functions,which results in inhibition of EPS secretion.国家自然科学基金资助项目,39900020号

Effect of Light and Temperature on the Cell Division in Coscinodiscus jonesianus

在不同的光温条件下，研究琼氏圆筛藻细胞分裂的昼夜变化。实验表明，该藻培养种群每昼夜形成三次分裂相，其细胞分裂呈现在光期快在暗期慢的特点，而分裂相的大小和定时则随光温条件的变化而变化。在温度27℃，光强度8000lX和光暗周期16：8H的条件下，该藻呈最大日增殖率（μ值为3.02次/d），显示琼氏圆筛藻为暖水性的生态特征。The effects of light and temperature on diel periodicity of cell division of Coscinodiscus jonesianus were carried out in laboratory condition.Results showed that there are three division phases each day.cell division quickly in light cycle and slowly in dark cycle.Results also indicated that the phase and the timing of cell division changed with the variation of light and temperature.The highest growth rate of C.jonesianus is 3.02/day when cultured in 27℃,8000L, and light/dark cycle of 16:8,which suggested that C jonesianus belongs to a warm temperature species

Effect of dissolved phosphorus on alkaline phosphatase activity in marine microalgae

在实验室批量培养条件下，测定了海洋微藻培养体系中碱性磷酸酶活力（APA）和各形态溶解磷的动态变化，分析了二者之间的关系.结果表明，在批量培养过程中，APA的动态变化呈“S“形曲线，各形态溶解磷在其变化过程中所起的调控作用不同，介质中溶解无机磷和小分子溶解有机磷的浓度是激发APA发生变化的主要调控因子，大分子溶解有机磷的浓度对APA的作用不明显，但APA的增大可加速微藻利用大分子溶解有机磷的速率.微藻的种类和丰度不影响APA的动态变化形式及其调控机理.It was thought that phosphorus licited the primary productivity in lake while nitrogen in ocean, but recent studies showed that phosphorus limited the phytoplankton growth in the specific coastal waters, results also indicated that Phytoplankton could utilize dissolved organic phosphorus (DOP) and alkaline phosphatase (AP) played an important role in the utilization of DOP.However, the variation and controlling mechanism of AP are still poorly understood.The present study focused on the effects of different species of dissolved phosphorus on the variation of AP in algal batch culture.The results showed that vacation of airline phosphatase activity (APA) was closed to "S" curve, different spotes of dissolved phosphorus had different effects on APA.The concentrations of dissolved inorganic phosphorus and small moleculal dissolved organic phosphorus had a sighficant effect on APA, while the concentration of large molecular dissolved organic phosphorus (LDOP) has little effect on APA, but the increasing of APA could accelerate the decomposing of LDOP in the medium.Results also showed that algae species and abundance had little effect on APA.国家自然科学基金!4920606

Research Progress on Extracellular Polymeric Substances of Marine Diatoms

近20年来,随着海洋科学研究的不断深入及一些海洋大项目(LOICZ,JGOFS)的实施,海洋生态学家在重新构建海洋食物网时发现,海洋藻类分泌的胞外多聚物(Extracellular Polymeric Substances,EPSs)是海洋碳的一个重要来源,它们可能直接参与海洋生态系统的碳循环、微食物环的组成、藻-菌及藻-藻的相互作用等过程,因而藻类胞外多聚物的研究引起了海洋学家的高度重视,成为当前海洋科学研究的一个热点。硅藻是海洋藻类中最重要的一大类群,也是海洋近岸水体中最主要的初级生产者,具有种类多、数量大、繁殖快等特点,在海洋生态系统的物质循环与能量流动中占有极其重要的地位。研究表明,许多硅藻(包括浮游硅藻和附着硅藻)在其生长过程中均能生产分泌胞外多聚物(EPSs),它是硅藻生命过程中不可或缺的一部分,在海洋生国家自然科学基金(39900020)资助;; 教育部青年骨干教师资