EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2014
·Vol. 2014
·期 36
·6156-6164
·
IF 2.965
Liru Cui,Huiming Lin,Chunyu Yang,Xiao Han,Ting Zhang,Fengyu Qu
Graphical A pH-responsive and magnetic-targeted drug-delivery system was prepared with a Fe 3 O 4 @mesoporous silica core–shell nanostructure as host. Au nanoparticles were used as the capping agent. These were connected to the surface of the mesopore through the hydrazone linkage to restrict the drug release. The system has potential applications in low-pH tissue-targeted therapy. A multifunctional nanocomposite has been successfully prepared for pH-responsive and magnetic-targeting drug delivery. First, Fe 3 O 4 @mesoporous silic (mSiO 2 ) core–shell nanoparticles were synthesized as the nanocapsules. Doxorubicin hydrochloride was adopted as the model drug; after drug loading, gold nanoparticles (5 nm) were connected to block the mesopore through the hydrazone linkage. The hydrazone bond, a typical acid-sensitive bond, could undergo hydrolysis in an acidic environment to induce the release of the capping agent, so that the multifunctional nanocomposite revealed acid-enhanced release performance. What's more, before reaching acid conditions, little premature release was found to take place. Cell experiments were also carried out to reveal the good biocompatibility, fast uptake, and improved toxicity toward HeLa cells. Thus, in association with the magnetic target, the multifunctional nanocomposite shows the potential application for some low-pH tissue-targeted therapy, such as for inflammation and tumors.
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RSC Advances
·
2015
·Vol. 5
·期 97
·79456-79462
·
IF 3.84
Zhuo Ma,Yunfeng Qiu,Yanmin Huang,Feng Gao,PingAn Hu
We report the eco-friendly chitosan assisted synthesis of 3D graphene@chitosan@Au nanosheet (3DG@CS@AuNSs) composites without using any toxic reductants or capping agents. The 3D graphene network consists of few-layer graphene sheets. One the one hand, the interfacial energy between graphene and Au nanostructures is significantly weakened due to the existence of chitosan polymers, serving as “glue” for anchoring Au nanosheets on the surface of 3D graphene. On the other hand, chitosan contains abundant hydroxyl and amine groups acting as reducing and stabilizing agents for the formation and even distribution of Au nanosheets. Mild redox reaction between hydrochloroauric ions and hydroxyl and amine groups occurred under thermal conditions due to the matching electrochemical potentials of the oxidants and reductants. The as-prepared 3DG@AuNSs exhibited much higher activities than that of 3DG@Au nanoaggregates towards the reduction of 4-nitrophenol, as well as more convenient recyclability than other supported Au NPs in terms of a robust free-standing foam structure. Furthermore, high performance liquid chromatography was also applied to monitor the emergence of 4-aminophenol during reaction. The present studies not only build a new route for the design of a robust and free-standing foam catalyst based on the integration of graphene and Au nanostructures by the assistance of a natural polymer, but also shed deep insight on the understanding of the synergistic catalytic activity towards nitrophenols.
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ChemSusChem
·
2013
·Vol. 6
·期 10
·1945-1951
·
IF 7.475
Wenjin Wang,Jie Zhang,Shengchun Yang,Bingjun Ding,Xiaoping Song
Graphical Not just another brick in the wall: Brick-like Au@Pd core–shell nanobricks (CNBs) with a concave surface were synthesized through a one-pot procedure, and show an enhanced performance towards ethanol electrooxidation. The improved performance of the CNBs is a result of the exposed stepped surfaces, high-index facets, and the synergistic effects of the core and shell metals. Au@Pd core–shell nanobricks (CNBs) with concave surfaces and Pd shells with a thickness of approximately 5 nm were synthesized by co-reduction of HAuCl 4 and H 2 PdCl 4 in the presence of Au seeds and Ag ions. These as-synthesized concave CNBs exhibit significantly enhanced catalytic activity for the electrooxidation of ethanol in alkaline media compared to the commercially-used Pd black. The improved performance of the Au@Pd CNBs can be attributed to the exposed stepped surfaces, high-index facets, and the synergistic effects of the core and shell metals.
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NANOTECHNOLOGY
·
2013
·Vol. 24
·期 24
·245601
·
IF 3.842
Miao Liang,Libing Wang,Xia Liu,Wei Qi,Rongxin Su,Renliang Huang,Yanjun Yu,Zhimin He
Bio-nanomaterials fabricated using a bioinspired templating technique represent a novel class of composite materials with diverse applications in biomedical, electronic devices, drug delivery, and catalysis. In this study, Au nanoparticles (NPs) are synthesized within the solvent channels of cross-linked lysozyme crystals (CLLCs) in situ without the introduction of extra chemical reagents or physical treatments. The as-prepared AuNPs-in-protein crystal hybrid materials are characterized by light microscopy, transmission electron microscopy, x-ray diffraction, and Fourier-transform infrared spectroscopy analyses. Small AuNPs with narrow size distribution reveal the restriction effects of the porous structure in the lysozyme crystals. These composite materials are proven to be active heterogeneous catalysts for the reduction of 4-nitrophenol to 4-aminophenol. These catalysts can be easily recovered and reused at least 20 times because of the physical stability and macro-dimension of CLLCs. This work is the first to use CLLCs as a solid biotemplate for the preparation of recyclable high-performance catalysts.
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Reaction Kinetics Mechanisms and Catalysis
·
2013
·Vol. 109
·期 2
·551-562
·
IF 1.104
Cui Wenjing,Zhu Huaiyong,Jia Meilin,Ao Wulan,Zhang Yulin,Zhaorigetu Bao
Imines were synthesized from benzyl alcohol and amines by using catalysts of gold nanoparticles supported on ZrO 2 (Au/ZrO 2 ). The effects of reaction time, temperature, gold loadings and base were investigated. High yields were achieved under moderate conditions (60 °C) in the presence of KOCH 3 . For instance, the yield of N -benzylidenebenzylamine produced from benzyl alcohol and benzylamine on 3 wt% Au/ZrO 2 is 87 %. The synthesis of imine involves two reaction steps: selective oxidation of benzyl alcohol to benzaldehyde and the coupling reaction of amines with benzaldehyde. In the first step, the base promotes the selective oxidation. The reactions of benzyl alcohol with three different amines, aniline, n -butylamine and benzylamine, were conducted to produce corresponding imines. The results show that the amine with stronger nucleophilicity has better ability to react with benzaldehyde in the second step, resulting in higher yield of the corresponding imine. We proposed a tentative mechanism for the synthesis process.
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RSC Advances
·
2015
·Vol. 5
·期 117
·96483-96487
·
IF 3.84
Ruike Li,Meicheng Li,Yingfeng Li,Pengfei Fu,Younan Luo,Rui Huang,Dandan Song,Joseph Michel Mbengue
Metal-assisted chemical etching is a very popular method of fabricating silicon nanostructures. For the dissolution and recrystallization of Ag and the inertia of Au, we present a co-catalytic mechanism of silicon etching using non-overlapping Au and Ag nanofilms. Meanwhile, two kinds of novel nanostructures are obtained by changing the relative positions of the two nanofilms. The results show that regardless of whether the Ag or Au nanofilm is the upper layer, the Ag nanofilm will first react to etch the silicon substrate into silicon nanowires (Si NWs). Afterwards, the Au nanofilm will re-etch the Si NWs into thick pillars (Ag upper) or ultrathin porous Si NWs (Au upper). It should be noted that the vertical etching rates of the two layers are not observably different, in contrast to when the Au and Ag nanofilms are used separately, in which the vertical etching rate of the Ag nanofilm is much higher than that of the Au nanofilm. This occurs because the subsequent re-etching process by the Au nanofilm is conducted at multiple surfaces because Au can generate excessive holes during the decomposition of hydrogen peroxide. Furthermore, this study presents a feasible method for the fabrication of individual, thick (∼200 nm) silicon pillars and ultrathin (∼25 nm) porous Si NWs. These insights are significant for the syntheses of many nanostructures.
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Journal of Physical Chemistry C
·
2015
·
IF 4.772
Rui Wang,Xiaohui Ji,Zhenzhen Huang,Yurui Xue,Dayang Wang,Wensheng Yang
In this work, SiO2@Au core–shell particles under ambient conditions were prepared by using 120 nm SiO2 spheres with ca. 4 nm Au nanoparticles decorated on the surfaces as seeds, the aqueous solutions of sodium citrate/HAuCl4 mixtures as growth solutions, and hydroxylamine as reducing agent. The morphology of the Au shells obtained on the SiO2 spheres was readily regulated only by the citrate-to-HAuCl4 molar ratio; no deliberate adjustment of the temperature and pH of the reaction media was needed. When the citrate-to-HAuCl4 molar ratio in the growth solution was below 4:1, the surfaces of the SiO2 spheres were covered with sparsely packed Au nanoparticles with sizes in the range of 20–40 nm, depending on the citrate-to-HAuCl4 molar ratio. When the citrate-to-HAuCl4 molar ratio in the growth solution was above 8:1, the surfaces of the SiO2 spheres were coated by complete, uniform Au nanoshells. Concomitant with this citrate-regulated morphology, the localized surface plasmon resonance peaks of the resulting SiO2@Au particles shifted from 611 nm for the sparse Au nanoparticle coating to 784 nm for the complete Au nanoshell coating. Furthermore, the sparsely packed Au nanoparticle coating showed stronger surface enhancement Raman spectroscopic signals than the uniform Au nanoshell coating, while the latter exhibit higher photothermal efficiency than the former.
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Chemistry-An Asian Journal
·
2016
·Vol. 11
·期 12
·1821-1827
·
IF 4.592
Yongfang Yang,Xiaolu Zhang,Hefang Wang,Honghao Tang,Lidong Xu,Hua Li,Lei Zhang
Graphical Scrolled structures : The heterogeneous graphene oxide-polydopamine-Au (GO–PDA–Au) nanoscrolls were prepared by rolling up GO–PDA–Au sheets through a simple lyophilization method. Polydopamine (PDA) attached at the surface of GO sheets served as binding reagents to anchor and disperse Au nanoparticles (NPs) uniformly (see scheme). Compared to GO–PDA–Au sheets, GO–PDA–Au nanoscrolls showed better electrocatalytic activity and electrochemical stability owing to their scrolled structure. Graphene oxide–polydopamine–Au (GO–PDA–Au) nanoscrolls were prepared by rolling up GO–PDA–Au sheets through a simple lyophilization method. The structure of GO–PDA–Au nanoscrolls and GO–PDA–Au sheets were compared by powder X-ray diffraction, Raman spectra, transmission electron microscopy, and scanning electron microscopy. The results demonstrated that the heterogeneous GO–PDA–Au nanoscrolls were synthesized successfully. Polydopamine (PDA) attached at the surface of GO sheets served as binding reagents to anchor and disperse Au nanoparticles (NPs). The electrocatalytic activity of methanol with GO–PDA–Au nanoscrolls and GO–PDA–Au sheets as electrodes were conducted. Compared to GO–PDA–Au sheets, GO–PDA–Au nanoscrolls showed better electrocatalytic activity and electrochemical stability owing to their scrolled structure. This article provides a simple and effective method to prepare GO nanoscrolls containing metal NPs that broadens the applications of the graphene-based materials in optical, magnetic, and catalytic fields.
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Inorganic Chemistry Frontiers
·
2016
·Vol. 3
·期 7
·934-943
·
IF 4.532
Xiankun Shao,Benxia Li,Baoshan Zhang,Liangzhi Shao,Yongmeng Wu
Constructing a core–shell nanostructured photocatalyst by integration of plasmonic metal nanocrystals and a semiconductor can offer large active metal/semiconductor interfacial areas and avoid aggregation of the metal nanocrystals. Herein, well-defined Au@ZnO core–shell nanostructures were prepared by coating ZnO on cetyltrimethylammonium bromide (CTAB) stabilized Au nanospheres in aqueous solution. The resultant core–shell nanostructures have Au-nanosphere cores with a diameter of ∼55 nm and ZnO shells with a thickness of ∼50 nm. After calcination at 350 °C in air, the mesoporous ZnO shell with higher crystallinity and a larger surface area was obtained without any significant change in the morphology or plasmon band of Au@ZnO. The specific surface plasmon resonance of the Au-nanosphere cores endows the Au@ZnO nanostructures with strong visible light absorption around 550 nm. The photocatalytic degradation of an organic pollutant was performed under simulated sunlight and monochromatic LED light with three different wavelengths (365 nm, 520 nm, 660 nm), demonstrating the enhanced photocatalysis of the Au@ZnO nanostructures. Furthermore, the Au@ZnO as a photoelectrode material presents a higher photocurrent density than that of pure ZnO nanoparticles under simulated sunlight. The electrochemical impedance spectra (EIS) Nyquist plots also confirm the higher charge transfer efficiency of the Au@ZnO nanostructures. Such plasmonic metal–semiconductor core–shell nanostructures would provide a desirable platform for studying plasmon-induced/enhanced processes and have great potential in light-harvesting applications.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2016
·
IF 2.76
Guohui Li,Kaiyue Sun,Dawei Li,Pengfei Lv,Qingqing Wang,Fenglin Huang,Qufu Wei
Bacterial cellulose-gold nanoparticles (BC-AuNPs) hybrid nanofibers were synthesized by in-situ chemical reduction. The obtained BC-AuNPs nanofibers were characterized by a series of analytical techniques. The results revealed that gold nanoparticles (AuNPs) were successfully deposited on the surfaces of bacterial cellulose nanofibers. Then, the as-prepared BC-AuNPs hybrid nanofibers were attached onto the electrode surface followed by adding a certain amount of laccase (Lac) and Nafion to construct novel a biosensing platform. The prepared electrochemical biosensor was employed to detect hydroquinone. The sensor showed excellent electrocatalysis towards dopamine with low detection limit (5.71 nM), and wide linear range (30–100 nM). Moreover, the biosensor also showed good repeatability, reproducibility, selectivity and stability and was successfully used in the detection of hydroquinone in lake water samples, thus providing a promising method for hydroquinone detection in water environments.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Shiyu Xu,Ying Wang,Ying Sun,Guiye Shan,Yanwei Chen,Yichun Liu
The cysteine (CYS)-stimulated aggregation of Au nanorods (NRs) is used as an auxiliary reporting system for the optical detection of copper ions. CYS-Au NRs show end-to-end and side-by-side assembly at strong acidic and basic condition, and corresponding LSPR peaks shift to red or blue. However, Cu 2+ can readily induce the end-to-end assembly of CYS-Au NRs based on the coordination between Cu 2+ and CYS at weak acidic condition (pH 5). The assembly of Cu 2+ -CYS-Au make the decrease of LSPR peak at 800 nm and appear a new peak at 1050 nm, which reduce their photothermal conversion efficiency under 808 nm laser irradiation. The different photothermal conversion efficiency has relation with the temperature change of Au NRs solution. So, a new nanosensor for detecting Cu 2+ is developed based on the varied photothermal effect. Different from colorimetric detection for Cu 2+ , the sensor of photothermal effect is more sensitive to low concentration of Cu 2+ . It shows high sensitivity and selectivity. Here, the detection limit for Cu 2+ is 5 nM.
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BIOSENSORS & BIOELECTRONICS
·
2016
·
IF 7.476
Hua Yang,Li Li,Yaping Ding,Daixin Ye,Yingzi Wang,Shiqiang Cui,Lanfeng Liao
A novel imprinted sensor for ultra-trace cholesterol (CHO) detection based on electropolymerized aminothiophenol (ATP) molecularly imprinted polymer (MIP) on a glassy carbon electrode (GCE) modified with dopamine@graphene (DGr) and bioinspired Au microflowers has been developed in this work. As the specific recognition element, the bioinspired Au microflowers were formed by Au nanoparticles (AuNPs) and wrapped by bionic polydopamine film (PDA) through electropolymerization method. These excellent biocompatible materials could capture the target CHO effectively. The morphology of the MIP modified electrode was characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The hydrogen-bonding interaction between templates and monomers was characterized by ultraviolet spectroscopy . Under the optimal experimental conditions, the sensor's linear response range was between 10 −18 and 10 −13 M, with a detection limit of 3.3×10 −19 M, which was much more sensitive than most available CHO detection methods in previously reports. Moreover, the MIP sensor exhibited high sensitivity for CHO, low interference, and good stability. The human serum samples analysis confirmed the applicability of this MIP sensor to quantitative analysis of ultra-trace CHO.
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