COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Yinchun Hu,Hui Yang,Renhu Wang,Menglan Duan
MOF-5 was prepared by hydrothermal method and Ag@MOF-5 nanoplates were obtained to improve the antibacterial activity and dispersion of Ag nanoparticles . MOF-5 and Ag@MOF-5 were characterized by scanning electron microscope (SEM), high-resolution transmission electron microscope and energy spectrum (HR-TEM&EDS), X-ray diffraction (XRD), infrared spectrum (FTIR) and thermal gravimetric analysis (TGA). MOF-5 was flaky crystals accumulated and complexed to form cube-like crystalline particles with the size of 20–50 micrometers, and it was destroyed in the process of loading nano-silver particles. Ag@MOF-5 nanoplates were nanoscale sheets, and 3–5 nm Ag nanoparticles were uniformly dispersed and loaded on nanoplates of MOF-5. The content of silver nanoparticles reached 13 wt% of Ag@MOF-5 total weight. The results of antibacterial experiment indicated that antibacterial ability of MOF-5 was limited, while Ag@MOF-5 showed good antibacterial ability to Escherichia coli and Staphylococcus aureus.
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Crystals
·
2021
·Vol. 11
·期 7
·769
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IF 2.589
Yazhou Qin,Binjie Wang,Yuanzhao Wu,Jiye Wang,Xingsen Zong,Weixuan Yao
Bimetallic nanoparticles have received extensive attention due to their unique physical and chemical properties, including enhanced optical properties, chemical stability, and better catalytic activity. In this article, we have successfully achieved the controllable preparation of Ag@Au nanoparticles via a seed-mediated growth method. By regulating the amount of seeds—silver nanospheres—we realized that Ag@Au nanoparticles gradually changed from spherical to a sea-urchin-like structure. The structure and composition of the prepared nanoparticles were characterized via scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and high-angle circular dark field scanning transmission electron microscopy (HAADF-STEM). In addition, we use the prepared Ag@Au nanoparticles as a substrate material for highly sensitive surface-enhanced Raman spectroscopy (SERS). Using 4-aminothiophenol (4-ATP) as the test molecule, we explored the SERS enhancement effects of Ag@Au nanoparticles with different structures. Furthermore, we used Ag@Au nanoparticles for SERS to detect the drug fentanyl, and realized the label-free detection of fentanyl, with the lowest detection concentration reaching 10−7M. This research not only provides a method for preparing bimetallic Ag@Au nanoparticles with different structures, but also provides a reference for the application of Ag@Au nanoparticles in the field of detection technology.Keywords:Ag@Au nanoparticle;core–shell structure;sea-urchin-like structure;SERS;fentanyl
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2021
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IF 4.098
Siqi Tang,Hongmei Liu,Yiran Tian,Dong Chen,Chenjie Gu,Guodong Wei,Tao Jiang,Jun Zhou
Recently, it is urgent to ameliorate the accumulation and quantification performances of surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-based LFIA) to promote its reliable clinical application. Herein, a smart hydrophilic-hydrophobic SERS-based LFIA strip was demonstrated by decorating Ag nanoplates with hydrophilic surface onto the specific regions of hydrophobic polymethylmethacrylate (PMMA) film with Raman internal standard (IS), which can unexpectedly inhibit the “coffee-ring phenomenon”. The target analytes were consequently enriched in the SERS-active Ag regions by the hydrophobic PMMA, considerably endowing the strip with amended quantitative monitoring ability. Aided by immunoprobes of flower-shaped Ag nanoplates, a limit of detection as 10 pg/mL and an outstanding correlation coefficient value (R 2 ) of 0.992 for carcinoembryonic antigen (CEA) were obtained by utilizing this SERS-based LFIA strip, which can be conducive to clinical monitoring and will broaden the field of vision for the point-of-care diagnostic technique.
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PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
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2021
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IF 5.645
Zongyuan Zhu,Yanbing Liu,Wenjie Cong,Xubo Zhao,Jidon Janaun,Tao Wei,Zhen Fang
A heterogeneous CaO/Ag nano catalyst was developed and applied for biodiesel production from transesterification of soybean oil. The silver performed synergistic effects with CaO on promoting biodiesel production. The CaO/Ag nano catalysts exhibited abundant strong basic sites with larger BET surface area (7.02 vs 2.05 m 2 /g), pore diameter (58.84 vs 37.08 nm) and pore volume (0.070 vs 0.016 cm 3 /g), which significantly reduced mass transfer resistance of triglycerides during transesterification and improved the mass transfer constants. Response surface methodology was applied to investigate the influence reaction parameters and optimize biodiesel yield. A maximized biodiesel yield of 90.95 ± 2.56 % was achieved using methanol:oil molar ratio of 13, CaO/Ag loading of 5%, reaction time of 90 min and reaction temperature of 72℃. The optimized biodiesel yield for CaO catalyzed transesterification was 88.40 ± 3.34 %, using similar reaction conditions but with 180 min of reaction time. Both nano catalysts were consecutively reused for five times. Kinetic and thermodynamic studies of CaO and CaO/Ag catalyzed transesterification were performed and compared. Economic evaluation of biodiesel production using CaO and CaO/Ag was performed and compared to provide insights for heterogeneous catalyst application for biodiesel production on industrial scale.
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高影响因子
CARBOHYDRATE POLYMERS
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2021
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IF 9.381
Sufeng Zhang,Chen Hua,Bin He,Pengbing Chang,Min Du,Ye Liu
Flexible electronics products have attracted wide attention because of their excellent flexibility, conductivity and stability. In this study, the liquid phase reduction method was used to in situ reduce fractal-structured silver particles (FSSPs) on cellulose surface to prepare conductive paper with excellent conductivity, and good stability and flexibility. The experimental results show that when the mass ratio of silver to cellulose was 1.5:1, the sheet resistance of conductive paper is as low as 0.02 Ω·sq −1 , and the conductivity reaches 1041.33 S cm −1 , which shows excellent conductivity. In order to expand the application of conductive paper in the field of flexible wearable electronic products, the mechanical stability and oxidation resistance of conductive paper were tested. The results show that the conductive paper has good stability and is expected to replace the flexible electronics products made of plastic.
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PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Yazhou Qin,Yuanzhao Wu,Binjie Wang,Jiye Wang,Weixun Yao
Compared with silver nanoparticles, gold nanoparticles have excellent chemical resistance and biocompatibility, while silver nanoparticles have more excellent local surface plasmon resonance characteristics than gold. In this article, we developed a simple method for growing island-shaped gold nanoparticles on the surface of silver nanowires (NWs), so that the prepared Ag@Au NWs have both the advantages of Au and Ag without their disadvantages. Furthermore, by changing the reaction parameters, we achieved the regulation of the density of island-shaped gold nanoparticles on the Ag NWs surface, thereby optimizing its LSPR performance. We use the prepared Ag@Au NWs as the base material for highly sensitive Surface enhanced Raman scattering (SERS) detection. By using 4-aminothiophenol (4-ATP) as the test molecule to explore the uniformity of the prepared SERS substrate, the detection limit of 4-ATP reached 10 -9 M. And 10 points were randomly selected for testing and the RSD was 7.4%, indicating the Ag@Au NWs SERS substrates had excellent uniformity. Furthermore, we have achieved highly sensitive SERS detection of 5 tropane alkaloids including L -Hyoscyamine, Anisodamine, Scopolamine Hydrobromide, scopolamine methyl bromide and scopolamine butyrate bromide. The limit of detection is 10 -9 M, 10 -10 M, 10 -9 M, 10 -9 M and 10 -10 M. Furthermore, by analyzing the obtained SERS spectra, we realized the differentiation of 5 kinds of tropane alkaloids by their characteristic peaks.
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Catalysts
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2020
·Vol. 10
·期 10
·1102
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IF 3.52
Fengyang Ju,Jinjin Zhang,Weiwei Lu
The electrochemical reduction of CO2is a promising way to recycle it to produce value-added chemicals and fuels. However, the requirement of high overpotential and the low solubility of CO2in water severely limit their efficient conversion. To overcome these problems, in this work, a new type of electrolyte solution constituted by ionic liquids and propylene carbonate was used as the cathodic solution, to study the conversion of CO2on an Ag electrode. The linear sweep voltammetry (LSV), Tafel characterization and electrochemical impedance spectroscopy (EIS) were used to study the catalytic effect and the mechanism of ionic liquids in electrochemical reduction of CO2. The LSV and Tafel characterization indicated that the chain length of 1-alkyl-3-methyl imidazolium cation had strong influences on the catalytic performance for CO2conversion. The EIS analysis showed that the imidazolium cation that absorbed on the Ag electrode surface could stabilize the anion radical (CO2•−), leading to the enhanced efficiency of CO2conversion. At last, the catalytic performance was also evaluated, and the results showed that Faradaic efficiency for CO as high as 98.5% and current density of 8.2 mA/cm2could be achieved at −1.9 V (vs. Fc/Fc+).Keywords:electrochemical reduction of CO2;ionic liquids;propylene carbonate;imidazolium cation
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Tong Wu,Hui Zheng,Yichuan Kou,Shilei Jin,Yuhong Jiang,Ming Gao,Lei Chen,Naveen Reddy Kadasala,Yang Liu
In this study, 3D Fe 3 O 4 micro-flowers were synthesized by the self-assembly approach, then rhombic dodecahedral Cu 2 O was successfully loaded onto their surface by wet chemical method . Ag nanocrystals were reduced in situ on the surface of Fe 3 O 4 /Cu 2 O composites to prepare novel Fe 3 O 4 /Cu 2 O/Ag composites. The composites were characterized by SEM, TEM, XRD , XPS, VSM and UV–Vis diffuse reflectance spectroscopy. The effect of Ag nanocrystals on the photocatalytic performance of the Fe 3 O 4 /Cu 2 O composites was investigated by the degradation of methyl orange under visible light irradiation, and the Fe 3 O 4 /Cu 2 O/Ag composites showed higher photocatalytic efficiency than the Fe 3 O 4 /Cu 2 O composites. Photoelectrochemical and PL measurements were carried out to investigate the synergistic effect between the semiconductors and Ag nanocrystals and it was confirmed that the Fe 3 O 4 /Cu 2 O/Ag composites effectively inhibited the recombination of electron-hole pairs, thus improving the photocatalytic activity. The fact that the Fe 3 O 4 /Cu 2 O/Ag composites could be magnetically recycled and that they retained more than 90% of their original activity after six repeated experiments indicates, that they show great potential for wastewater treatment applications.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Amir Mahmoud Makin Adam,Madeha Ishag Adam,Chunmiao Zhang,Baffa Haruna,Mingzhu Chi,Xiong Li,Jia Kang Wan,Mujtaba Aminu,Girum Girma Bizuneh,Min Deng,Aimei Zhu,Qiugen Zhang,Qinglin Liu
Developing highly active Pd-based nanocatalysts with a well-organized structure is desired for direct alcohol fuel cell commercialization. In this study, room temperature seed mediated growth strategy has been successfully developed to prepare ternary Pd@Cd x -Ag y core-shell as advanced novel non-Pt anode nanocatalysts for ethanol oxidation reaction EOR in alkaline electrolyte . The introduction of oxophilic Cd and Ag metals into Pd nanocatalysts can reduce the adsorption energy of OH ads on the Pd@Cd x -Ag y nanocatalysts and inhibit the CO ads on the Pd surface. Morphological characterization demonstrates that the as-synthesized Pd@Cd x -Ag y nanocatalysts are well-organized core-shell nanostructure with Pd NPs as the core and Cd-Ag alloy as the shell. Moreover, electrochemical results indicate that the Pd@Cd 1 -Ag 1 core-shell catalyst exhibit a remarkable electrochemical activity ( 2995.76 mA mg Pd − 1 ), excellent CO tolerance and long-term durability compared to those of Pd@Cd ( 1285.9 mA mg Pd − 1 ), Pd@Ag ( 2423.52 mA mg Pd − 1 ) and commercial Pd/C (JM) ( 477.4 mA mg Pd − 1 ) nanocatalysts. The excellent catalytic activity and stability of Pd@Cd 1 -Ag 1 nanocatalyst can be associated to their huge electrochemical active surface area, positive influence of Cd-Ag NPs on Pd NPs and the unique well-organized core-shell nanostructure. These results suggested that the as-synthesized Pd@ C d x -Ag y core-shell could serve as advanced catalysts towards alkaline DEFCs.
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高影响因子
MATERIALS & DESIGN
·
2020
·
IF 6.289
Lizhu Guan,Ling Weng,Qiong Li,Xiaorui Zhang,Zijian Wu,Yingyi Ma
With a strong ability in tailoring molecular structure, nanoscale morphology, and nanodomains, the ferromagnetic metal-organic framework (MOF, M = transition metal) has been considered an advantageous candidate material for dielectric nanocomposites. Herein, a pristine content-controlled Ag nanoparticle driving Ni metal-organic framework (Ag-NiMOF) ultra-thin 2D ferroelectric nanoplatelets have been synthesized by a two-step method, and applied to the PVDF-based energy storage materials. Comprehensive tests and multi-physics simulations have been conducted on the electrical properties of materials. The electric displacement-electric field (D-E) hysteresis loops of the composites show that the discharge density of 6.987 J/cm 3 ~ 2300 kV/cm has been achieved with a 10 wt% filler addition, namely 10Ag-NiMOF/PVDF, which indicates a 5.36 times increase in the discharge density. Finite element simulation further verifies the improvement of the displacement and electrical breakdown strength of the composites. This high performance indicates that both of the centrosymmetric lattice nanodomains of NiMOF and the electrons introduced by Ag nanoparticle would help induce greater polarization in the nanocomposite. Furthermore, the Coulomb blockade effect exerted by the Ag nanoparticle with an appropriate particle size and a fractional concentration can significantly improve the electrical breakdown strength. This 2D hybrid particle provides a novel idea for modifying dielectric composites for high storage device applications.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2020
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IF 4.551
Peng Xu,Zhenguo Wu,Wei Dai,Yang Wang,Mengke Zheng,Xiaodan Su,Zhaogang Teng
Multiple Ag nanoparticles loaded hollow mesoporous carbon spheres (Ag@HMCSs) are successfully synthesized through a “soft-to-hard templating” approach. In this method, polyacrylic acid (PAA) colloids are used as stabilizers for Ag nanoparticles and serve as soft templates for a sol-gel process with tetraethyl orthosilicate and polymerization process of resorcinol-formaldehyde resin (RF resin) in one pot. Ag@HMCSs are obtained after carbonization of the RF resin layer and selectively etching the SiO 2 component. Ag@HMCSs exhibit a spherical morphology with a mean size of approximately 140 nm and a high surface area of 239.67 m 2 g −1 , and the average size of encapsulated silver nanoparticles are about 10 nm without aggregation. The prepared Ag@HMCSs show excellent catalytic activity and stability for reduction of 4-nitrophenol, Congo red, and Rhodamine B. Therefore, this “soft-to-hard templating” approach represents a promising strategy for the preparation of high-performance carbon nanoparticle-supported catalysts.
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高影响因子
Surfaces and Interfaces
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2021
·
IF 4.837
Xueyan Bian,Jiangtao Xu,Jing Yang,Ka-lam Chiu,Shouxiang Jiang
In this study, silver (Ag) is deposited onto polyester fabric through a magnetron sputtering system. The argon flow rate and sputtering time are both controlled to produce Ag nanoparticles of different sizes on the polyester substrate with different gap distances. The scanning electron microscope images, X-ray diffraction spectra, and Raman intensity are used to evaluate the produced substrates. With an average grain size of ~ 46 nm, Ag particles deposited at an argon flow rate of 200 sccm on polyester fabric (AP-200) provides the best SERS performance of 33,625.34 counts towards a 10 −3 M MB solution. The results show that the AP-200 SERS substrate is highly sensitive, reproducible and stable, and it also demonstrates good reusability. Image of “hotspots” that forms between two Ag nanoparticles based on electric field distribution is simulated by the finite-difference time-domain (FDTD) method which is used to explain the phenomenon of signal enhancement. In addition, AP-200 is used to directly collect R6G from an irregular surface, and shows high sensitivity with a limit of detection of 1 ppm.
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危险品化学品经营许可证（带存储）