Metal Immiscibility Route to Synthesis of Ultrathin Carbides,Borides, and Nitrides

Ultrathin ceramic coatings are of high interest as protective coatings from aviation to biomedical applications. Here, a generic approach of making scalable ultrathin transition metal‐carbide/boride/nitride using immiscibility of two metals is demonstrated. Ultrathin tantalum carbide, nitride, and boride are grown using chemical vapor deposition by heating a tantalum‐copper bilayer with corresponding precursor (C₂H₂, B powder, and NH₃). The ultrathin crystals are found on the copper surface (opposite of the metal–metal junction). A detailed microscopy analysis followed by density functional theory based calculation demonstrates the migration mechanism, where Ta atoms prefer to stay in clusters in the Cu matrix. These ultrathin materials have good interface attachment with Cu, improving the scratch resistance and oxidation resistance of Cu. This metal–metal immiscibility system can be extended to other metals to synthesize metal carbide, boride, and nitride coatings.     

Development of Polymeric Nanoprobes with Improved Lifetime Dynamic Range and Stability for Intracellular Oxygen Sensing

A class of core‐shell nanoparticles possessing a layer of biocompatible shell and hydrophobic core with embedded oxygen‐sensitive platinum‐porphyrin (PtTFPP) dyes is developed via a radical‐initiated microemulsion co‐polymerization strategy. The influences of host matrices and the PtTFPP incorporation manner on the photophysical properties and the oxygen‐sensing performance of the nanoparticles are investigated. Self‐loading capability with cells and intracellular‐oxygen‐sensing ability of the as‐prepared nanoparticle probes in the range 0%–20% oxygen concentration are confirmed. Polymeric nanoparticles with optimized formats are characterized by their relatively small diameter (<50 nm), core‐shell structures with biocompatible shells, covalent‐attachment‐imparted leak‐free construction, improved lifetime dynamic range (up to 44 μs), excellent storage stability and photostability, and facile cell uptake. The nanoparticles’ small sensor diameter and core‐shell structure with biocompatible shell make them suitable for intracellular detection applications. For intracellular detection applications, the leak‐free feature of the as‐prepared nanoparticle sensor effectively minimizes potential chemical interferences and cytotoxicity. As a salient feature, improved lifetime dynamic range of the sensor is expected to enable precise oxygen detection and control in specific practical applications in stem‐cell biology and medical research. Such a feature‐packed nanoparticle oxygen sensor may find applications in precise oxygen‐level mapping of living cells and tissue.     

核壳结构二氧化硅/磁性纳米粒子的制备及应用

核壳结构二氧化硅/磁性纳米粒子作为一种新型功能复合材料在生物医学方面有重要应用前景.综述了核壳结构二氧化硅/磁性纳米粒子的各种制备方法以及国内外在核壳结构二氧化硅/磁性纳米粒子制备方面的研究新进展,并对其在生物医学上的应用作了介绍.     

Selective Patterning of Gold Surfaces by Core/Shell,Semisoft Hybrid Nanoparticles

The generation of patterned surfaces with well‐defined nano‐ and microdomains is demonstrated by attaching core/shell, semisoft nanoparticles with narrow size distribution to microdomains of a gold‐coated silicon wafer. Near monodisperse nanoparticles are prepared using reversible addition‐fragmentation chain transfer (RAFT) polymerization, initiated from a silica surface, to prepare a polystyrene shell around a silica core. The particles are then used as‐prepared, or after aminolysis of the terminal thiocarbonyl group of the polystyrene shell, to give thiol‐terminated nanoparticles. When gold‐coated silicon wafers are immersed into very dilute suspensions of these particles (as low as 0.004 wt%), both types of particles are shown to adhere to the gold domains. The thiolated particles adhere selectively to the gold microdomains, allowing for microdomain patterning, while particles that contain the trithiocarbonate functionality lead to a much more even coverage of the gold surface with fewer particle aggregations.     

Preparation and characterization of ZnO/ZnS core/shell nanocomposites through a simple chemical method

In this paper, we reported the preparation of ZnO/ZnS core/shell nanocomposites by sulfidation of ZnO nanostructures via a simple hydrothermal method. The precursors of bare ZnO nanoparticles and ZnO nanorods were synthesized by a surfactant-assisted hydrothermal growth. The structural, morphological, and element compositional analysis of bare ZnO nanostructures and ZnO/ZnS core/shell nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy techniques. The XRD results indicated that the phase of bare ZnO nanoparticles and ZnO nanorods was wurtzite structure, and the phase of coated ZnS nanoparticles on the surface of bare ZnO nanostructures was sphalerite structure with the size of about 8 nm. Photoluminescence measurement was carried out, and the PL spectra of ZnO/ZnS core/shell nanocomposites revealed an enhanced UV emission and a passivated orange emission compared to that of bare ZnO nanostructures. In addition, the growth mechanism of ZnO/ZnS core/shell nanostructures through hydrothermal method was preliminarily discussed.     

Synthesis of high magnetic moment CoFe nanoparticles via interfacial diffusion in core/shell structured Co/Fe nanoparticles

We report the synthesis of high magnetic moment CoFe nanoparticles via the diffusion of Co and Fe in core/shell structured Co/Fe nanoparticles. In an organic solution, Co nanoparticles were coated with a layer of Fe to form a Co/Fe core/shell structure. Further raising the solution temperature led to inter-diffusion of Co and Fe and formation of CoFe alloy nanoparticles. These nanoparticles have high saturation magnetization of up to 192 emu/g CoFe and can be further stabilized by thermal annealing at 600 °C. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users. These two authors made an equal contribution to the work.     

Scalable Synthesis of Triple‐Core–Shell Nanostructures of TiO2@MnO2@C for High Performance Supercapacitors Using Structure‐Guided Combustion Waves

Core–shell nanostructures of metal oxides and carbon‐based materials have emerged as outstanding electrode materials for supercapacitors and batteries. However, their synthesis requires complex procedures that incur high costs and long processing times. Herein, a new route is proposed for synthesizing triple‐core–shell nanoparticles of TiO₂@MnO₂@C using structure‐guided combustion waves (SGCWs), which originate from incomplete combustion inside chemical‐fuel‐wrapped nanostructures, and their application in supercapacitor electrodes. SGCWs transform TiO₂ to TiO₂@C and TiO₂@MnO₂ to TiO₂@MnO₂@C via the incompletely combusted carbonaceous fuels under an open‐air atmosphere, in seconds. The synthesized carbon layers act as templates for MnO₂ shells in TiO₂@C and organic shells of TiO₂@MnO₂@C. The TiO₂@MnO₂@C‐based electrodes exhibit a greater specific capacitance (488 F g^?1 at 5 mV s^?1) and capacitance retention (97.4% after 10 000 cycles at 1.0 V s^?1), while the absence of MnO₂ and carbon shells reveals a severe degradation in the specific capacitance and capacitance retention. Because the core‐TiO₂ nanoparticles and carbon shell prevent the deformation of the inner and outer sides of the MnO₂ shell, the nanostructures of the TiO₂@MnO₂@C are preserved despite the long‐term cycling, giving the superior performance. This SGCW‐driven fabrication enables the scalable synthesis of multiple‐core–shell structures applicable to diverse electrochemical applications.     

PSA@Fe3O4 doped CdS的制备及流变性能研究

用简单的湿化学方法首次制备了PSA@Fe3O4 doped CdS核壳结构复合微球.采用X射线衍射(XRD)、透射电子显微镜(TEM)、物性测试系统(PPMS)和荧光光谱(PL)对制备的样品进行表征、观察和性质测定.结果显示所制备粒子晶型稳定,尺寸均匀,分散性好.另外,所制备的样品在室温下表现出超顺磁性和荧光性质,充分显示磁性和半导体性质的良好结合.用PSA@Fe3O4 doped CdS颗粒作为磁性粒子制备磁性液体,对其在磁场下的运动和流变性能进行了研究.