ZnO纳米棒阵列到纳米管结构的自转化机制及其在相变封装材料中的应用

In the emerging field of nanoscience, tubular structures have been attracting remarkable interest due to their well-defined geometry, high specific area, and exceptional physical and chemical properties. Among them, oriented ZnO tubular arrays are regarded as promising candidates for various applications such as optoelectronics, solar cells, sensors, field emission, piezoelectrics, and catalysis. Although template-directed and selective dissolution synthesizing strategies are commonly used to prepare ZnO nanotubes, repeatability and large scale preparation are still challenging. In this study, ZnO nanotube arrays were controllably prepared by tuning the hydrothermal parameters, without the use of any additives. The mechanism underlying the self-conversion of ZnO nanorods to nanotubes was comprehensively studied based on the surface energy theory. It has been proved that the metastable top surface of the ZnO nanorods dissolves preferentially to reach a stable state during the hydrothermal growth. The specific surface energy of different crystal faces of ZnO nanorods was calculated using molecular dynamics simulation. The top surface of the ZnO nanorod, the Zn-terminated [0001] face, demonstrated much higher surface free energy than did the lateral faces, which indicated that the self-dissolution of top face (002) is energetically favorable. The self-conversion behavior of ZnO nanorod arrays with different diameters was specifically investigated by adjusting the initial precursor concentration, density of the crystal seed layers, and growth time. The dissolution-crystallization equilibrium concentration, determined by crystal surface energy, was found to be a key factor for the formation of the tubular structure. Notably, the critical equilibrium conditions for the self-conversion of ZnO nanorods to nanotubes, including zinc ion concentration and pH, have been identified by studying parameters corresponding to the dissolution-crystallization equilibrium for the metastable top surface of the ZnO nanorods. The preparation of the ZnO nanotube arrays was successfully accelerated and simplified via two-step procedure: (1) preparation of ZnO nanorod arrays and (2) self-conversion of ZnO nanorods to nanotubes. The preparation method based on the self-conversion mechanism from rods to tubes for polar oxides is simpler and more easily controllable as compared to the reported methods involving variety of additives. Because of the advantages of adaptability to a wide range of substrates, excellent conducting properties, and filling ability, the prepared ZnO nanotube array films were used in encapsulating phase-change materials. The encapsulated phase-change material exhibited excellent heat storage/release properties and heat conductivities. This indicates the potential application of precision devices for temperature control.     

两个包含联苯类三羧酸配体的钴(Ⅱ)和镍(Ⅱ)配位聚合物的合成、晶体结构及磁性质

采用水热方法,用2种联苯类三羧酸配体:联苯-2,4,4′-三羧酸(H3btc)、5-(3,4-二羧基苯基)吡啶甲酸(H_3dppa)和4,4′-联吡啶(4,4′-bipy)分别与CoCl_2·6H_2O和NiCl_2·6H_2O反应,合成了具有一维双螺旋链结构的配合物[Co(μ_2-H_2btc)2(4,4′-bipy)_2]_n(1)以及二维层状配位聚合物{[Ni_3(μ4-dppa)_2(H_2O)_6]·2H_2O}n(2),并对其结构和磁性质进行了研究。结构分析结果表明2个配合物都属于三斜晶系,P1空间群。配合物1具有一维双螺旋链结构,而且这些链通过O-H…O/N氢键作用进一步形成了三维超分子框架。而配合物2具有基于一维链单元的二维层状结构。4,4′-联吡啶在配合物1和2中分别起配位作用和模板作用。研究表明,配合物1中相邻钴离子间存在铁磁相互作用。     

两个基于刚性线型三羧酸配体的镍(Ⅱ)配合物的合成

采用水热方法,选用刚性线型三羧酸配体(H3L)和2,2′-联吡啶(2,2′-bipy)与NiCl2·6H2O分别在120和160℃温度下反应,得到了一个具有零维双核镍结构的配合物[Ni2(μ-HL)2(2,2′-bipy)2(H2O)4]·6H2O (1)和一个一维链状配位聚合物{[Ni(μ-HL)(2,2′-bipy)(H2O)2]·H2O}n(2),并对其结构和磁性质进行了研究。结构分析结果表明2个配合物均属于三斜晶系,P1空间群。配合物1具有零维双核镍结构,而且这些双核镍单元通过O-H…O/N氢键作用进一步形成了三维超分子框架,而配合物2具有一维链结构。2个配合物的结构差异可能是由于水热反应温度不同造成的。研究表明,配合物2中相邻镍离子间存在反铁磁相互作用。     

相变微胶囊型吸热剂MPCM-2的制备及其控热效果

以十二水合磷酸氢二钠为芯材,乙基纤维素为壁材,采用原位聚合工艺制备了相变微胶囊型吸热剂MPCM-2,其结构和性能经IR、 DSC、TG和粒度分析表征。结果表明：MPCM-2的相变温度为43.34和58.77 ℃,总相变焓值为144.82 J·g^-1,包裹率为67.5%; MPCM颗粒中径为57.26 μm,同时,MPCM-2应用于深水固井水泥浆体系可实现对水化热及水化温升的有效控制。     

3位间接连接有叔胺(仲胺)氮原子的3-季碳氧化吲哚化合物的合成

以3-卤氧化吲哚为起始原料,1,8-二氮杂二环十一碳-7-烯为催化剂,在二氯甲烷中与1-甲基吲哚经取代反应,或在甲苯溶液中于120 ℃条件下与吲哚（吲哚苯环上可连接有取代基）直接发生取代反应,合成了7个3位间接连接有叔胺（仲胺）氮原子的3-季碳氧化吲哚化合物,收率分别为80%~89%和 53%~70%,其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征。     

Effective Removal of Tetracycline by Using Biochar Supported Fe3O4 as a UV-Fenton Catalyst

Novel Fe3O4-decorate hierarchical porous carbon skeleton derived from maize straw(Fe3O4@MSC)was synthesized by a facile co-precipitation process and a calcination process,which was developed as a UV assisted heterogeneous Fenton-like catalyst.The as-synthesized catalysts were characterized via X-ray powder diffraction(XRD), scanning electron microscope(SEM),transmission electron microscope(TEM),Brunauer-Emmet-Teller(BET)and vibrating sample magnetometer(VSM)at room temperature.The morphology and structure analysis revealed that the as-prepared Fe3O4@MSC retained the original pore morphology of the maize straw material.The non-uniform poly- hedral Fe3O4 grew on the whole surface of the MSC,which reduced the aggragation of Fe3O4 and provided more active sites to strengthen the UV-assisted Fenton-like reaction.As a result,the tetracycline(TC)degradation efficiency after 40 min reaction and total organic carbon(TOC)removal efficiency after 2 h reaction of Fe3O4@MSC catalyzing UV-Fenton system reached 99.2%and 72.1%,respectively,which were more substantial than those of Fe3O4@MSC/H2O2(31.5%and 2%),UV/H2O2 system(68%and 23.4%)and UV/Fe3O4/H2O2(80% and 37.5%).The electron spin resonance(ESR)results showed that the ·OH played an important role in the catalytic reaction.A possible degradation pathway of TC was proposed on the basis of the identified intermediates.Overall,the UV assisted heterogeneous Fenton-like process in Fe3O4@MSC improved the cycle of Fe^3+/Fe^2+ and activated the interfacial catalytic site,which eventually realized the enhancement of degradation and mineralization to tetracycline.     

Enhanced Peroxymonosulfate Activation by NixCo1-xOOH for Efficient Catalytic Oxidation of Organic Pollutants

Peroxymonosulfate(PMS) has received increasing attention as viable technology for recalcitrant organics removal from polluted waters. Although promising, alternative heterogeneous catalysts with stable structure, strong hydrophilicity, environmental friendliness and excellent catalytic performance are highly desirable to facilitate the wide industrialization of PMS. In this work, Ni doped CoOOH catalyst was employed as PMS activator. Ni dopant had a significant influence on the morphology, structure and catalytic performance of CoOOH. NiojCoo.gOOH exhibited the best catalytic performance. Reaction rate ofNio.2Coo.8OOH was 2, 4, and 4.4 times that of CoOOH, CoFe2O4 and CO3O4, respectively. Moreover, Ni。2C00.8OOH/PMS system had potential application to organic pollutants and displayed a great catalytic activity over a broader pH value(e.g., 4-10). More importantly, Ni doping accelerated the transfonnation of Co(Ⅲ) and Co(Ⅱ) and formed active species CoOH^+ and NiOH^+ which were responsible to the enhancement of PMS activation.OH, SO4^-:O2^- and 1^O2 were detected, indicating both non-radical and radical processes in the Nio.2Coo.8OOH/PMS system. These findings provide a promising alternative to mixed-metal oxyhydroxides catalysts for PMS activation, demonstrating a great potential in environmental remediation and wastewater treatment.     

Reductive Amination of Carbonyl Compounds with Ammonia and Hydrogenation of Nitriles to Primary Amines with Heterogeneous Cobalt Catalysts

Reductive amination of aldehydes/ketones with aqueous NH3 and hydrogenation of nitriles to primary amines with Co catalysts were reported. Co@NC-700 exhibited remarkable activity and high selectivity for the reductive amination of aldehydes/ketones with aqueous NH3 and the hydrogenation of nitriles to primary amines. Several primary amines can be obtained with good to excellent yields via the reductive amination of aldehydes/ketones and the hydrogenation of nitriles. The nitrogen-doped carbon(C)-supported Co@NC-700 metal catalyst was prepared via the pyrolysis of bioMOF Co/adenine in activated C. Co@NC-700 can be reused five times without evident loss of activity.     

Self-cleaning Anti-fouling TiO2/Poly(aryl ether sulfone) Composite Ultrafiltration Membranes

A series of novel TiO2/poly(aryl ether sulfone) ultrafiltration membranes with anti-fouling and self-cleaning properties was designed and prepared. First, anti-photocatalytic degraded fluorine contained polv(aryl ether sulfone) matrix(PAES-F) was synthesized. Then the composite membranes were prepared via TiO2 nanopartides and PAES-F polymer matrix by solution blending and non-solvent induced phase inversion methods. Further, separation efficiency, fouling behavior and self-cleaning property of the composite ultrafiltration(UF) membranes were investigated by dead-end filtration experiments using a polyacn lamide solution. The composite UF membranes exhibited outstanding self-cleaning efficiency and anti-photocatalytic degraded property after exposure to simulated sunliglit irradiation.The water flux recovery ratios(FRR)of the optimal composite UF membranes could reach 74.24%, which was attributable to photocatalytic degradation of the organic contaminant by TiO2. And the retention rates of the composite UF membranes could maintain over 97%, which indicated the excellent photocatalytic degradation resistance of the fluorine contained PAES-F matrix. The novel high perfomiance composite UF membranes have a broad application prospect in water treatment.     

多维度信息记录与再现技术的进展

随着信息技术的高速发展和大数据时代的到来,有效存储和管理海量数据的要求对数据存储技术提出了严峻挑战。光存储技术在能耗、容量、成本、寿命、安全等方面的优势,使其正逐渐成为未来数据存储的主流技术。本文围绕光存储技术的维度展开论述,纵向介绍了几种常用的光存储技术。目前以光盘为代表的二维面存储技术,存储容量已接近其理论存储极限（23.5 GB/disc）;以双光子吸收技术、全息存储技术为代表的三维体存储技术,其存储容量相较二维存储技术提升了2~4个数量级;五维存储技术进一步扩展了数据存储的维度。可以预见,未来光存储技术会在大存储容量、超高存取速度、高性能存储材料、多维度存储技术等方面取得突破和进展。