聚硫堇和磁性核/壳纳米粒子CoFe_2O_4/SiO_2修饰电极对多巴胺的测定

制备了聚硫堇(PTh)-磁性核/壳纳米粒子CoFe2O4/SiO2修饰电极。研究了神经递质多巴胺(DA)在该修饰电极上的电化学行为。实验表明,PTh-CoFe2O4/SiO2复合膜修饰电极对DA的电催化作用优于PTh修饰电极。在pH7.5的PBS中,DA在该修饰电极上的CV曲线于-0.16V和-0.22V处出现一对灵敏的氧化还原峰,峰电流显著增加。差分脉冲伏安法(DPV)氧化峰电流ipa与DA浓度在1.2×10-7～3.6×10-5mol/L范围内呈良好的线性关系,线性回归方程ipa(μA)=5.307c(μmol/L)+0.7891,r=0.9923,检出限为6.0×10-8mol/L(S/N=3)。常见物质对DA的检测无干扰,DA注射液样品检测结果与中国药典2010版(二部)规定方法一致。

Au@SnO_2核/壳纳米粒子制备及其氧气气敏性能的研究

在预先制备的Au纳米粒子溶液中还原SnCl2合成AuSn纳米粒子,然后采用阶段性升温氧化获得Au@SnO2核/壳纳米粒子。采用XRD和TEM对合成的纳米粒子进行表征。在200℃和300℃分别测量Au@SnO2纳米粒子薄膜电阻随氧压变化的特性,结果表明,300℃条件下,当氧压为1.013×105Pa时Au@SnO2薄膜电阻是初始状态的13.75倍;200℃条件下,当氧压为1.013×105Pa时Au@SnO2薄膜电阻是初始状态的3.67倍。

贵金属核壳纳米粒子最新研究进展

贵金属核壳纳米粒子具有独特的光、电和催化性质,使其在材料科学、生物物理、分子电子学以及基于表面增强效应的荧光工程学领域具有极其广泛的应用前景。本文综述了贵金属核壳纳米粒子的制备方法及应用,并对贵金属核壳材料的发展进行了展望。

Fe3O4@Au核/壳结构纳米粒子合成研究进展

Fe3O4@Au核/壳纳米粒子具有独特的磁性和光学性质,已广泛应于生物医学领域.概述了近年来Fe3O4@Au核/壳纳米粒子的合成方法.详细介绍了Fe3O4@Au核/壳纳米粒子双层结构和多层复合结构的合成方法.

Ni@Pd core-shell nanoparticles supported on a metal-organic framework as highly efficient catalysts for nitroarenes reduction

Ni@Pd core-shell nanoparticles with a mean particle size of 8–9 nm were prepared by solvothermal reduction of bivalent nickel and palladium in oleylamine and trioctylphosphine.Subsequently,the first-ever deposition of Ni@Pd core-shell nanoparticles having different compositions on a metal-organic framework（MIL-101）was accomplished by wet impregnation in n-hexane.The Ni@Pd/MIL-101 materials were characterized by powder X-ray diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,and energy-dispersive X-ray spectroscopy and also investigated as catalysts for the hydrogenation of nitrobenzene under mild reaction conditions.At 30 °C and 0.1 MPa of H2 pressure,the Ni@Pd/MIL-101 gives a TOF as high as 375 h–1 for the hydrogenation of nitrobenzene and is applicable to a wide range of substituted nitroarenes.The exceptional performance of this catalyst is believed to result from the significant Ni-Pd interaction in the core-shell structure,together with promotion of the conversions of aromatics by uncoordinated Lewis acidic Cr sites on the MIL-101 support.

Ordered mesoporous carbon supported bifunctional PtM(M=Ru,Fe,Mo)electrocatalysts for a fuel cell anode

The deposition onto an ordered mesoporous carbon（OMC）support of well dispersed PtM（M = Ru,Fe,Mo）alloy nanoparticles（NPs）were synthesized by a direct replication method using SBA-15 as the hard template,furfuryl alcohol and trimethylbeneze as the primary carbon sources,and metal acetylacetonate as the alloying metal precursor and secondary carbon source.The physicochemical properties of the PtM-OMC catalysts were characterized by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray absorption near edge structure,and extended X-ray absorption fine structure.The alloy PtM NPs have an average size of 2-3 nm and were well dispersed in the pore channels of the OMC support.The second metal（M）in the PtM NPs was mostly in the reduced state,and formed a typical core（Pt）-shell（M）structure.Cyclic voltammetry measurements showed that these PtM-OMC electrodes had excellent electrocatalytic activities and tolerance to CO poisoning during the methanol oxidation reaction,which surpassed those of typical activated carbon-supported PtRu catalysts.In particular,the PtFe-OMC catalyst,which exhibited the best performance,can be a practical anodic electrocatalyst in direct methanol fuel cells due to its superior stability,excellent CO tolerance,and low production cost.

Regulating surface In–O in In@InO_(x) core‐shell nanoparticles for boosting electrocatalytic CO_(2) reduction to formate

To solve the excessive emission of CO_(2) caused by the excessive use of fossil fuels and the corre‐sponding environmental problems,such as the greenhouse effect and climate warming,electrocat‐alytic CO_(2) reduction to liquid fuel with high selectivity is of huge significance for energy conversion and storge.Indium has been considered as a promising and attractive metal for the reduction of CO_(2) to formate.However,the current issues,such as low selectivity and current activity,largely limit the industrial application for electrocatalytic CO_(2) reduction,the design optimization of the catalyst structure and composition is extremely important.Herein,we develop a facile strategy to regulate surface In–O of In@InO_(x) core‐shell nanoparticles and explore the structure‐performance relation‐ship for efficient CO_(2)‐to‐formate conversion though air calcination and subsequent in situ electro‐chemical reconstruction,discovering that the surface In–O is beneficial to stabilize the CO_(2) interme‐diate and generate formate.The optimized AC‐In@InO_(x)‐CNT catalyst exhibits a C1 selectivity up to 98%and a formate selectivity of 94%as well as a high partial formate current density of 32.6 mA cm^(-2).Furthermore,the catalyst presents an excellent stability for over 25 h with a limited activity decay,outperforming the previously reported In‐based catalysts.These insights may open up op‐portunities for exploiting new efficient catalysts by manipulating their surface.

Nanoscale architecture of ceria-based model catalysts: Pt-Co nanostructures on well-ordered CeO_(2)(111) thin films

We have prepared and characterized atomically well-defined model systems for ceria-supported Pt-Co core-shell catalysts. Pt@Co and Co@Pt core-shell nanostructures were grown on well-ordered CeO2(111) films on Cu(111) by physical vapour deposition of Pt and Co metals in ultrahigh vacuum and investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy. The deposition of Co onto CeO2(111) yields CoCeO2(111) solid solution at low Co coverage(0.5 ML), followed by the growth of metallic Co nanoparticles at higher Co coverages. Both Pt@Co and Co@Pt model structures are stable against sintering in the temperature range between 300 and 500 K. After annealing at 500 K, the Pt@Co nanostructure contains nearly pure Co-shell while the Pt-shell in the Co@Pt is partially covered by metallic Co. Above 550 K, the re-ordering in the near surface regions yields a subsurface Pt-Co alloy and Pt-rich shells in both Pt@Co and Co@Pt nanostructures. In the case of Co@Pt nanoparticles, the chemical ordering in the near surface region depends on the initial thickness of the deposited Pt-shell. Annealing of the Co@Pt nanostructures in the presence of O2 triggers the decomposition of Pt-Co alloy along with the oxidation of Co, regardless of the thickness of the initial Pt-shell. Progressive oxidation of Co coupled with adsorbate-induced Co segregation leads to the formation of thick CoO layers on the surfaces of the supported Co@Pt nanostructures. This process is accompanied by the disintegration of the CeO2(111) film and encapsulation of oxidized Co@Pt nanostructures by CeO2 upon annealing in O2 above 550 K. Notably, during oxidation and reduction cycles with O2 and H2 at different temperatures, the changes in the structure and chemical composition of supported Co@Pt nanostructures were driven mainly by oxidation while reduction treatments had little effect regardless of the initial thickness of the Pt-shell.

One-Step Synthesis of Magnetically Recyclable Au/Co/Fe Triple- Layered Core-Shell Nanoparticles as Highly Efficient Catalysts for the Hydrolytic Dehydrogenation of Ammonia Borane

Magnetically recyclable Au/Co/Fe core-shell nanoparticles （NPs） have been successfully synthesized via a one-step in situ procedure. Transmission electron microscope （TEM）, energy dispersive X-ray spectroscopic （EDS）, and electron energy-loss spectroscopic （EELS） measurements revealed that the trimetallic Au/Co/Fe NPs have a triple-layered core-shell structure composed of a Au core, a Co-rich inter-layer, and a Fe-rich shell. The Au/Co/Fe core-shell NPs exhibit much higher catalytic activities for hydrolytic dehydrogenation of ammonia borane （NHBBH3, AB） than the monometallic （Au, Co, Fe） or bimetallic （AuCo, AuFe, CoFe） counterparts.

Oligonucleotide delivery by chitosan-functionalized porous silicon nanoparticles

Porous silicon nanoparficles （pSiNPs） are a promising nanocarrier system for drug delivery owing to their biocompatibility, biodegradability, and non-inflammatory nature. Here, we investigate the fabrication and characterization of thermally hydrocarbonized pSiNPs （THCpSiNPs） and chitosan-coated THCpSiNPs for therapeutic oligonucleotide delivery. Chitosan coating after oligonucleotide loading significantly improves sustained oligonucleotide release and suppresses burst release effects. Moreover, cellular uptake, endocytosis, and cytotoxicity of oligonucleotide-loaded THCpSiNPs have been evaluated in vitro. Standard cell viability assays demonstrate that cells incubated with the NPs at a concentration of 0.1 mg/mL are 95% viable. In addition, chitosan coating significantly enhances the uptake of oligonucleotide-loaded THCpSiNPs across the cell membrane. Moreover, histopathological analysis of liver, kidney, spleen, and skin tissue collected from mice receiving NPs further demonstrates the biocompatible and non-inflammatory properties of the NPs as a gene delivery vehicle for intravenous and subcutaneous administration in vivo. Taken together, these results suggest that THCpSiNPs provide a versatile platform that could be used as efficient vehicles for the intracellular delivery of oligonucleotides for gene therapy.

Synthesis of Ag@Cu_2O core-shell metal-semiconductor nanoparticles and conversion to Ag@Cu core-shell bimetallic nanoparticles

Ag@Cu2O core-shell metal-semiconductor nanoparticles(NPs) were prepared by using solution phase strategy. It was found that Ag@Cu2O core-shell NPs were easily converted to Ag@Cu bimetallic core-shell NPs with the help of surfactant PVP and excessive reducer ascorbic acid in air at room temperature, which is a unique phenomenon. Varying volumes of Ag colloidal solutions were added into the reaction mixtures containing fixed initial concentrations of Cu2+ and PVP, Ag@Cu2O and Ag@Cu core-shell NPs with fixed core size but varying outer shell thicknesses could be obtained. The composites, structures, morphologies and extinction properties of Ag@Cu2O and Ag@Cu core-shell NPs were systematically characterized by XRD, TEM and extinction spectra. Both of these NPs show wide tunable optical properties. The extinction peaks could be shifted from 421 nm to 700 nm. FTIR results reveal that Cu+ ions on the surface of Cu2 O nanocrystalline coordinate with N and O atoms in PVP and further are reduced to metallic Cu by excessive ascorbic acid and then form a nucleation site on the surface of Cu2 O nanocrystalline. PVP binds onto a different site to proceed with the reduction until all the Cu sources in Cu2 O NPs are completely assumed. And the shell of Cu2 O is converted to Cu shell. The synthesis approach in this paper is simple and also a promising reference for synthesizing other core-shell NPs. Ag@Cu2O NPs can be easily converted to Ag@Cu NPs in air at room temperature, which is promising to be used in electronic devices.