Search for potential K ion battery cathodes by first principles

An important challenge facing K-ion batteries lies in exploring earth-abundant and safe cathode materials that can provide high capacity with high migration rate of K ions.Here,we propose a simple and efficient method for searching potential K cathode materials with first principles calculations.Our screening is based on combinations of weight capacity,K ion occupation ratio,volume change per K,and valence limit.With this screening method we predicted a series of potential K ions cathodes with favorable electrochemical performance,such as K₂VPO₄CO₃-like structures with 1 D diffusion channels,3 D channel structures K₂CoSiO₄,layered materials KCoO₂,KCrO₂,KVF₄ and K₅V₃F₁₄,and others.These potential cathodes have small volume changes,suitable voltage,and high capacity,with small diffusion barriers.They may be useful in K-ion batteries with high energy density and rate performance.     

Evolution of Artificial Base Pairs with Hydrogen Bond Complementarity

Artificial base pairs,from the perspective of synthetic biology,are designed to contain the features of modularity,orthogonality,and manipulability.And the development of artificial base pairs has beat endowed with responsibility to understand the biological process,improve the recognition capacity and stability of aptamers,and develop the nucleoside drugs,diagnosis,and drag delivery.In this review,we first gave a concise introduction of artificial base pairs based on their interaction modes including alternative hydrogen bonding,hydrophobic interaction,and metal coordination.Then we displayed the detailed information of artificial base pairs with hydrogen bonding interaction,and analyzed how the changes of their structures affect their functions.Subsequently,we highlighted the applications of functional artificial base pairs in aptamer discovery,diagnosis,and drug delivery.Finally,an insight into the remaining challenges and future perspective of the artificial bases was provided.     

Highly stable aqueous rechargeable Zn-ion battery: The synergistic effect between NaV_6O_(15) and V_2O_5 in skin-core heterostructured nanowires cathode

The aqueous rechargeable Zn-ion batteries based on the safe,low cost and environmental benignity aqueous electrolytes are one of the most compelling candidates for large scale energy storage applications.However,pursuing suitable insertion materials may be a great challenge due to the strong electrostatic interaction between Zn^{^(2+})and cathode materials.Hence,a novel NaV₆O₁₅/V₂O₅ skin-core heterostructure nanowire is reported via a one-step hydrothermal method and subsequent calcination for high-stable aqueous Zn-ion batteries(ZIBs).The NaV₆O₁₅/V₂O₅ cathode delivers high specific capacity of 390 m Ah/g at 0.3 A/g and outstanding cycling stability of 267 m Ah/g at 5 A/g with high capacity retention over 92.3%after 3000 cycles.The superior electrochemical performances are attributed to the synergistic effect of skin-core heterostructured NaV₆O₁₅/V₂O₅,in which the sheath of NaV₆O₁₅ possesses high stability and conductivity,and the V₂O₅ endows high specific capacity.Besides,the heterojunction structure not only accelerates intercalation kinetics of Zn²⁺transport but also further consolidates the stability of the layers of V₂O₅ during the cyclic process.This work provides a new perspective in developing feasible insertion materials for rechargeable aqueous ZIBs.     

Enhanced hydrogen evolution reaction in Sr doped BiFeO_3 by achieving the coexistence of ferroelectricity and ferromagnetism at room temperature

The perovskite transition metal oxide(TMO) has been considered in electrocatalysis for the modern clean energy technologies as its high electrochemical activity and low cost. The atomic scale engineering to the local stoichiometry of single crystal TMO provides a clue of the relation between electronic structure and catalytic performance. Here we report a hydrogen evolution reaction(HER) activity enhancement ~ 1761% of Bi_0.85Sr_0.15FeO_3 compared to the pure BiFeO_3. By the systemic investigation of the Sr doping level of Bi_1-xSr_xFeO_3(BSFO), it is found that the HER enhancement originates from the improvement of ferromagnetism of BSFO without obvious scarification of the ferroelectricity at the room temperature. The multiple ferroic orderings in BSFO are beneficial for HER activity, which offers the strengthen of hybridization of Fe 3d and O2 p orbitals from the view of ferromagnetism, and the assistance of electron drift by spontaneous electric polarization. Our study not only affords the strategy of developing multiple ferroic orderings in TMO, but also facilitates the atomic scale understanding of the improved HER activity.     

High-capacity Li-rich Mn-based Cathodes for Lithium-ion Batteries

Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process,voltage decay during cycling,inefficient cyclability and rate capability.Many attempts have been performed to solve such issues,including the mechanism study and strategies to improve the electrochemical performance.This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.     

电解质对两性药物分子盐酸氯丙嗪的胶团生长的影响

The effect of electrolytes on the micellar behavior of an amphiphilic drug,chlorpromazine(CPZ)hydroehloride,was studied using cloud point(CP)and dye solubilization techniques.In the presence of KBr,increase because of deprotonation of drug molecules at high pH. The visible absorbance increased(due to dye solubilization)with the increase in pH from 6.5 to 6.9,which indicated micellar growth.At fixed pH(6.7),addition of inorganic salts(KF,KC1,effecfiveness being in the order:F-Na >K ,which Was explained by considering cognizance of their hydrated radii.Compared with anions,their effect was small.Increase in[CPZ]caused micellar growth and hence the CP as well as the visible absorbance increased.The overall behavior Was discussed in terms of electrostatic interactions and micellar growth.     

对金属钠保存在煤油中机理的研究

长期以来人们一直认为金属钠保存在煤油中是因为金属钠的密度比煤油的密度大且金属钠和煤油不发生化学反应的缘故,因此在教学中形成一个教师都默认学生也认可的事实,这个事实就是金属钠能保存在煤油中有2点原因:     

有机铅卤化物钙钛矿:冉冉升起的高效太阳能电池(英文)

正1.Introduction We have recently witnessed a breakthrough in highly effi-cient solar cells, where the organolead halide perovskite, CH3NH3PbI3, was used as an absorber of sunlight. The perov-skite was used to sensitize mesoporous TiO2 films in a solid-state mesoscopic solar cell to deliver a power conversion     

江苏盱眙出土夹纻胎漆器的测试分析

采用激光拉曼光谱、X射线荧光光谱、红外吸收光谱等方法对盱眙出土的夹纻胎漆器进行了分析研究.研究发现漆膜中的红色颜料和暗黑色颜料分别是HgS和CuS;漆灰的填料以粘土类物质为主,存在着加入骨灰的工艺;生漆被使用在漆灰制作、色漆调制等方面,起到了成膜剂的作用;麻胎之间采用漆灰作为胶合剂.     

Large-area periodic lead halide perovskite nanostructures for lenticular printing laser displays

Lenticular printing technique provides a promising way to realize stereoscopic displays,especially,when microscopic optical structures are integrated into light-emitting materials/devices.Here,we fabricated large-area periodic structures with a spatial resolution at a wavelength scale from hybrid perovskite materials via a space-confined solution growth method.It takes advantages of both high refractive index contrast and high luminescence brightness,which allows the optical modulation on not only the reflection of illumination,but also the light emission from hybrid perovskites.The distributed feedback within these periodic structures significantly improves the degree of polarization and directionality of laser actions while their threshold is also reduced.These findings enable us to present a prototype of lenticular printing laser displays that vary emission colors at different view angles,which may find applications in creating high-resolution and high-contrast holographical images.     

Ordered nickel oxide nanowire arrays and their optical absorption properties

Ordered NiO nanowire arrays embedded in anodic alumina membranes have been prepared by using an electrochemical deposition method. After annealing at 300 °C, the NiO nanowire arrays were characterized using SEM, TEM, SAED, and XRD. SEM and TEM observations reveal that these nanowires are dense, continuous and arranged roughly parallel to one another. XRD and SAED analysis together indicate that these NiO nanowires crystallize with a polycrystalline structure. The optical absorption band gap of NiO nanowire arrays is 3.74 eV, and no obvious blue shift or red shift with respect of that of the bulk NiO can be observed.     

非水体系中电解镍中间产物制备纳米NiO

采用纯镍为阳极，乙酰丙酮和乙醇的混合溶液中加入少量有机胺导电盐为电解液，施加一定电流使镍溶解，然后将电解液直接水解，控制一定的水解条件，制备得到纳米NiO粉体. 采用拉曼光谱、红外光谱、元素分析、XRD 和TEM 分别对电解得到的纳米NiO前驱体和纳米NiO进行了分析与表征, 并探讨了电化学溶解镍金属法制备纳米NiO反应的影响因素.电化学溶解镍金属得到的前驱体为Ni(OEt)2(acac)2,这种不溶性镍醇盐配合物升温至40～50℃即可溶解于乙醇溶液中,可直接应用于溶胶 凝胶(Sol gel)过程.水解后的纳米NiO呈无定形结构, 350 ℃煅烧后形成立方晶型NaCl结构, 纳米NiO经600 ℃煅烧后粒径分布在5～10 nm. 该方法理论上为二价不溶性金属醇盐经溶胶 凝胶工艺制备纳米氧化物材料提供了一条新的途径.     

大豆蛋白改性TiO_2的制备及其可见光催化性能

采用溶胶-凝胶法制备了系列大豆蛋白改性TiO_2复合催化剂.通过元素分析、粒度分析、X射线衍射(XRD)、场发射扫描电镜(FESEM)、紫外-可见漫反射光谱(UV-Vis)、电化学等方法对所制备的样品进行了表征,以亚甲基蓝为目标降解物,研究了大豆蛋白改性TiO_2的可见光催化性能.结果表明,大豆蛋白改性可以一步实现C、N、H多种非金属元素共掺杂;相比纯TiO_2,改性后复合催化剂的比表面积增大;所有样品均为锐钛矿相;煅烧温度为400℃时,复合催化剂的可见光吸收发生明显红移,其禁带宽度较纯TiO_2窄化了0.32 e V;大豆蛋白改性后,复合材料的光电流密度增大;在可见光照射下,光催化反应2 h时,大豆蛋白改性TiO_2的亚甲基蓝降解效率最高可达79.4%.     

Au nanoparticle monolayers covered with sol-gel oxide thin films: optical and morphological study

In this work, we provide a detailed study of the influence of thermal annealing on submonolayer Au nanoparticle deposited on functionalized surfaces as standalone films and those that are coated with sol-gel NiO and TiO(2) thin films. The systems are characterized through the use of UV-vis absorption, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and spectroscopic ellipsometry. The surface plasmon resonance peak of the Au nanoparticles was found to red-shift and increase in intensity with increasing surface coverage, an observation that is directly correlated to the complex refractive index properties of Au nanoparticle layers. The standalone Au nanoparticles sinter at 200 °C, and a relationship between the optical properties and the annealing temperature is presented. When overcoated with sol-gel metal oxide films (NiO, TiO(2)), the optical properties of the Au nanoparticles are strongly affected by the metal oxide, resulting in an intense red shift and broadening of the plasmon band; moreover, the temperature-driven sintering is strongly limited by the metal oxide layer. Optical sensing tests for ethanol vapor are presented as one possible application, showing reversible sensing dynamics and confirming the effect of Au nanoparticles in increasing the sensitivity and in providing a wavelength dependent response, thus confirming the potential use of such materials as optical probes.     

焙烧温度对Ni-Mg基蜂窝状催化剂生物燃气重整调变性能的影响

采用浸渍法制备了Ni、Mg双金属负载在堇青石表面形成的蜂窝状催化剂,研究了焙烧温度对催化剂结构和生物质粗燃气重整反应性能的影响.结果表明,在不同焙烧温度下主要有NiO和NiMgO₂固溶体物相生成.相比于其他焙烧温度,催化剂在650 ℃焙烧温度下更有利于镍活性金属位的分散和活性位数量的增加.在干重整反应条件下,CH₄、CO₂的转化率以及H₂、CO产率随焙烧温度的升高呈现先增加后降低的变化趋势,在650 ℃焙烧温度下达到最高.在水蒸气重整反应条件下主要发生烃类产物与H₂O和CO₂的重整反应以及水煤气变换反应,焙烧温度的升高有利于水煤气反应的进行.此外,焙烧温度对于干重整反应条件下的H₂/CO体积比调节影响较小,而对于水蒸气重整反应条件下的H₂/CO体积比可进行选择性调节.     

Thermal decomposition of ammonium perchlorate activated via addition of NiO nanocrystals

This work reported on the thermal decomposition of ammonium perchlorate activated by addition of NiO nanocrystals with different surface areas. NiO samples were characterized by X-ray diffraction (XRD), transition electron microscope (TEM), Brunauer-Emmett-Teller (BET) technique, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. With increasing annealing temperature, the surface areas of NiO samples reduced from 108.6 to 0.9 m² g⁻¹. The catalytic activities of NiO nanocrystals on the thermal decomposition of ammonium perchlorate were investigated by thermogravimetric analysis (TG) coupled with differential thermal analysis (DTA). With addition of NiO nanocrystals, thermal decomposition temperature of AP decreased greatly. Larger surface areas of NiO nanocrystals promoted the thermal decomposition of AP.     

侧链胆甾液晶聚合物及弹性体的液晶性能研究

把胆甾液晶单体 4 烯丙氧基苯甲酸胆甾醇酯 (Mch)分别和向列液晶单体 4 烯丙氧基苯甲酰氧基 4′ 甲氧基苯 (Mn) ,向列液晶交联剂 2 叔丁基对苯二酚双 [4 (6 丙烯酰氧基己氧基 )苯甲酸酯 ](Mnc)接枝到聚硅氧烷链上 ,得到系列侧链液晶聚合物Pn 系列和液晶弹性体Pe 系列 .通过热分析、偏光显微分析和X 射线分析等手段分别研究了向列液晶单体和向列液晶交联剂对含同一胆甾液晶基元聚合物的影响 .结果表明 ,向列液晶单体的摩尔百分比在 80 %以下 ,液晶聚合物Pn 系列为胆甾型液晶 ,在研究的范围内 ,液晶弹性体Pe 系列也为胆甾型液晶 ,Pn 系列和Pe 系列都具有较宽的液晶相范围 ,热分解温度均在 2 80℃以上 .     

甲烷催化燃烧中制备参数对NiO/CuO-ZrO2催化剂高温反应性能的影响

采用溶胶凝胶－超临界干燥的方法制备了NiO/CuO-ZrO2催化剂，分别考察了焙烧温度、活性组分含量对催化剂甲烷燃烧性能的影响，并利用XRD、物理吸附等手段考察了两个参数对催化剂性能影响的本质原因，发现NiO/CuO-ZrO2催化剂具有较高的催化活性，较好的高温（1 000 ℃）反应稳定性，焙烧温度对催化剂的影响很大，500 ℃是合适的焙烧温度，通过试验发现活性组分NiO为5 mol％时催化剂适于在相对较低的温度下使用，而NiO为15 mol％时，催化剂具有较好的高温稳定性。     

Synthesis of Benzo[α] phenoxazin—5—one Derivatives and Their Interactions with DNA

The spectroscopic properties of benzo[a] phenoxazin-5-one derivatives(3a-3m)including newly synthesized 3k-3m from 4-nitrosoaniline hydrochlorides and ethyl 1,3-dihydroxy-2-naphthoate were studied.Compound 31 was converted into a covalent product with DNA,which had a blue shift of the fluorescence maximum,Compounds 3a-3k were fornd to undergo interation with DNA and their complexes with DNA had a red shift of the fluorescence maximum and showed increasing melting temperature of DNA,compound 3m-DNA had a blue shift of the fluorescence maximum to 3m and showed decreasing melting temperature of DNA.     

超音速气流粉碎下NiO纳米棒的低温固相制备

采用超音速气流粉碎技术低温固相合成NiO纳米颗粒前驱体,并通过在650～900 ℃下, NaCl熔盐介质中对前驱体进行焙烧,制备得到NiO纳米棒。采用XRD、SEM、TEM测试技术对NiO前驱体、NiO纳米棒的结构和形貌进行了表征。结果表明,前驱体为直径约25 nm球形颗粒,随着焙烧温度升高,逐渐生成直径为300 nm,长度约十几微米的纳米棒。反应过程中熔盐介质是纳米颗粒前驱体生长的关键因素。