SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2018
·
IF 2.88
Jian Zhu,Xiao-Hong Chen,Jian-Jun Li,Jun-Wu Zhao
In this work, the novel tetrapod gold nanostars with four specific numbers of sharp tips were synthesized with good uniformity, high yield and chemical stability. The size of tetrapod gold nanostars has been increased effectively by increasing the amount of HAuCl 4 or DEA added to the reaction solution, and the corresponding in-plane localized surface plasmon resonance (LSPR) band can shift from 700 to 1100 nm. In order to combine the advantages of different metals, the Ag-coated tetrapod gold nanostars were prepared with different Ag coating thicknesses by increasing the volume of AgNO 3 . With the increase of Ag coating thickness, the morphology of the nanoparticles has changed from gold nanostars with four sharp tips to bimetallic cuboids with four sharp tips and finally to crore-shell cuboids completely. The surface-enhanced Raman scattering (SERS) activity of Ag-coated tetrapod gold nanostars has also been improved with the different Ag coating thicknesses. Combined the tip effect and the enhancement effect of Ag, the SERS activity has the strongest enhancement when the four sharp tips of tetrapod gold nanostars are not completely coated by the Ag layer but still exposed to the outsides. For tetrapod gold nanostars with larger size to grow Ag-coated tetrapod gold nanostars, the bimetallic cuboids with four sharp tips nanostructure have the biggest SERS enhancement factor (EF) of 1.73 × 10 6 for Rhodamine 6G (R6G), making it an ideal candidate in SERS-based sensing application.
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高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Mingpeng Chen,Dongming Zhang,Jicu Hu,Huapeng Wang,Yumin Zhang,Kejin Li,Qian Rong,Shiqiang Zhou,Jin Zhang,Zhongqi Zhu,Qingju Liu
Highly sensitive and selective detection against toluene gas remains a tremendous challenge in gas sensor applications . In this work, a series of molecular imprinted Ag-LaFeO 3 nanoparticles (IAL NPs) were synthesized in a microwave-assisted colloidal route. Especially, the one prepared with optimal amount of imprint molecules (IAL-2 NPs) have a response of 24.0 to 5 ppm toluene at the optimum working temperature of 215 °C with negligible responses to the other test gases, exhibiting enhanced gas sensing properties for toluene gas at a relatively low working temperature. The improved performance can be attributed to the favorable effect of microwave radiation, the molecular imprinting structure and the sensitization of Ag, which illuminates that IAL-2 NPs is a potential candidate for toluene detection.
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ANALYST
·
2018
·Vol. 144
·期 2
·521-529
·
IF 3.864
Yuhua Dong,Chengqian Duan,Qinglin Sheng,Jianbin Zheng
In this work, a novel non-enzymatic hydrogen peroxide sensor, Ag@zeolitic imidazolate framework-67 (Ag@ZIF-67)/glassy carbon electrode (GCE), was fabricated by a simple method at room temperature. The morphology and structure of Ag@ZIF-67 were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, atomic absorption spectrophotometry, and N2 absorption isotherms, which indicated that core–shell Ag@ZIF-67 was successfully synthesized with a porous rhombic dodecahedron structure. Electrochemical investigations demonstrated that the Ag@ZIF-67/GCE had strong electrocatalytic activity towards hydrogen peroxide reduction with a low detection limit of 1.5 μM (S/N = 3), a fast response time of 3 s, and three different linear relationships in the ranges of 5.0 μM–275 μM, 775 μM–2775 μM, and 4775 μM–16 775 μM with sensitivities of 27 μA mM−1 cm−2, 13 μA mM−1 cm−2, and 5.3 μA mM−1 cm−2, respectively. Moreover, the fabricated sensor exhibited an excellent recovery rate in real sample analysis of medical hydrogen peroxide disinfectant. These results proved that Ag@ZIF-67/GCE is an effective electrochemical sensor for detecting hydrogen peroxide.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Jing Zou,Dongpeng Mao,Andrew Thye Shen Wee,Jizhou Jiang
Ultrathin (UT) g-C 3 N 4 with a thickness of ∼2 nm was prepared via a facile thermal exfoliation method using bulk g-C 3 N 4 as precursor. The UT-g-C 3 N 4 sample obtained exhibited a large specific surface area of 192.9 m 2 ·g −1 . The UT-g-C 3 N 4 /Ag hybrids were fabricated by a photo-assisted reduction technique. The morphology, microstructure and composition of the UT-g-C 3 N 4 /Ag hybrids were systematically characterized by transmission electron microscopy (TEM), aberration-corrected scanning transmission electron microscopy (STEM), STEM-energy dispersive X-ray (EDX) spectrometry, atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). Based on electrochemical impedance spectroscopy (EIS) results, the optimal UT-g-C 3 N 4 /Ag hybrids displayed a faster electron transfer rate in comparison of UT-g-C 3 N 4 and bulk g-C 3 N 4 . Moreover, in the presence of a phosphate buffer solution (pH = 6.0), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results showed that the UT-g-C 3 N 4 /Ag hybrids coated on glassy carbon electrode (denoted as UT-g-C 3 N 4 /Ag/GCE) exhibited excellent electrochemical properties for l -tyrosine detection. It is observed that the electrochemical response of was linear in the concentration range of 1.00 × 10 −6 to 1.50 × 10 −4 mol L −1 with a limit of detection (S/N = 3) of 1.40 × 10 −7 mol L −1 , superior to the other reported sensors. The developed UT-g-C 3 N 4 /Ag/GCE sensor was employed for l -tyrosine detection in commercial l -tyrosine tablet samples, and the recovery of 97.2–99.3% was observed. This proposed g-C 3 N 4 -based electrochemical sensor provides a rapid and sensitive sensing method for l -tyrosine detection in real samples.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Qiwen Zhang,Yongli Shen,Yufan Hou,Liting Yang,Baili Chen,Zhen Lei,Weiqing Zhang
The composition-activity relationship is highly desirable for electrocatalytic nitrogen reduction reaction (NRR) because it could guide the rational design of efficient NRR catalysts. In this work, the composition effect of Ag-based alloy nanotubes on electrocatalytic NRR activity is systematically investigated. It is found that, among AgAu nanotubes with atomic ratio from 8:1 to 1:2, Ag 2 Au 1 alloy nanotubes achieve the largest enhancement for NRR catalytic activity. Specifically, the NH 3 production rate and faradaic efficiency of Ag 2 Au 1 nanotubes are 21.7 μg h −1 mg cat −1 and 3.8% at −0.30 V vs. RHE, respectively, which were 3.0 and 3.6 times higher than those of Ag nanowires . Compared with Ag 2 Pd 1 and Ag 2 Pt 1 nanotubes, Ag 2 Au 1 hollow nanotubes also exhibit a better NRR catalytic activity. Theoretical calculation results indicate that the negative ion characteristic of Au atoms in the Ag 2 Au 1 alloy is favorable for the adsorption and activation of N 2 . Moreover, Ag 2 Au 1 nanotubes showed stable NH 3 yield rate and faradaic efficiency up to 18 h, revealing its great potential for promising NRR electrocatalysis .
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Materials
·
2019
·Vol. 12
·期 16
·2630
·
IF 2.972
Yuyao Zhang,Jun Li,Wenyao Li,Danning Kang
TiO2is regarded as a prospective electrode material owing to its excellent electrochemical properties such as the excellent cycling stability and the high safety. However, its low capacity and low electronic conductivity greatly restrict the further improvement in electrochemical performance. A new strategy was put forward to solve the above defects involved in TiO2in which the low capacity was enhanced by nanomerization and porosity of TiO2, and the low electronic conductivity was improved by introducing Ag with a high conductivity. One-dimensional mesoporous Ag nanoparticles-embedded TiO2nanofibers (Ag@TiO2nanofibers) were successfully synthesized via a one-step electrospinning process combined with subsequent annealing treatment in this study. The microstructure and morphology of mesoporous TiO2@Ag nanofibers were confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption. TiO2nanofibers mainly consisted of a large amount of anatase TiO2, accompanied with traces of rutile TiO2. Ag nanoparticles were uniformly distributed throughout TiO2nanofibers and promoted the transformation of TiO2from the anatase to the rutile. The corresponding electrochemical performances are measured by galvanostatic charge-discharge, cycle stability, rate performance, cycle voltammetry, and electrochemical impedance spectroscopy measurements in this research, with pristine TiO2nanofibers as the reference. The results indicated that the introduction of Ag nanoparticles into TiO2nanofibers significantly improved the diffusion coefficient of Li ions (5.42 × 10−9cm2⋅s−1for pristine TiO2, 1.96 × 10−8cm2⋅s−1for Ag@TiO2), and the electronic conductivity of TiO2(1.69 × 10−5S⋅cm−1for pristine TiO2, and 1.99 × 10−5S⋅cm−1for Ag@TiO2), based on which the comprehensive electrochemical performance were greatly enhanced. The coulombic efficiency of the Ag@TiO2nanofibers electrode at the first three cycles was about 56%, 93%, and 96%, which was higher than that without Ag (48%, 66%, and 79%). The Ag@TiO2nanofibers electrode exhibited a higher specific discharge capacity of about 128.23 mAh⋅g−1when compared with that without Ag (72.76 mAh·g−1) after 100 cycles at 100 mA·g−1. With the current density sharply increased from 40 mA·g−1to 1000 mA·g−1, the higher average discharge capacity of 56.35 mAh·g−1was remained in the electrode with Ag, when compared with the electrode without Ag (average discharge capacity of about 12.14 mAh·g−1). When the current density was returned to 40 mA·g−1, 80.36% of the initial value was returned (about 162.25 mAh·g−1) in the electrode with Ag, which was evidently superior to that without Ag (about 86.50 mAh·g−1, only 55.42% of the initial value). One-dimensional mesoporous Ag@TiO2nanofibers can be regarded as a potential and promising candidate as anode materials for lithium ion batteries.Keywords:electrospinning;titanium oxide;sliver;mesoporous nanofibers;lithium ion battery
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高影响因子
Journal of Environmental Chemical Engineering
·
2018
·
IF 0
Qingyong Li,Jiacheng Yao,Muhammad Arif,Ting Huang,Xiaoheng Liu,Guorong Duan,Xujie Yang
In this work, we first successfully designed and fabricated the ternary plasmonic Ag/β-Ag 2 WO 4 /WO 3 photocatalysts with different contents of Ag/β-Ag 2 WO 4 particles in situ decorated on the surface of WO 3 nanoplates by a simple precipitation method at room temperature condition. The photocatalytic activity of as-prepared samples was investigated by degradation of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under visible-light irradiation. It was found that the prepared 40 wt% Ag/β-Ag 2 WO 4 /WO 3 photocatalyst showed the highest photocatalytic RhB efficiency with 83.21 and 86.83 times higher than those of pure WO 3 and Ag/β-Ag 2 WO 4 samples, respectively. The highly enhanced photocatalytic performance was attributed to the Z-scheme mechanism in this ternary composites, in which Ag particles play a crucial role by the surface plasmon resonance (SPR) effect; meanwhile, Ag particles also can work as the charge transmission-bridge, giving rise to effectively restraining recombination of the photogenerated charge carriers. This novel ternary Ag/β-Ag 2 WO 4 /WO 3 nanostructures may provide an appropriate insight in the consideration as an ideal candidate in environmental remediation.
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JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Dongliang Qian,Dongyun Chen,Najun Li,Qingfeng Xu,Hua Li,Jinghui He,Jianmei Lu
Water pollution has led to increased attention on wastewater treatment and renewable industries. Various materials have been developed for removing pollutants from water. However, materials capable of emulsion separation and soluble-contaminant degradation in a single step are rare. We report a TiO 2 /sulfonated graphene oxide/Ag nanoparticle (TSA) membrane, which possesses useful wettability and photocatalytic properties. A photocatalytic TiO 2 nanorod array-based mesh with favorable wettability properties is integrated with a sulfonated graphene oxide/Ag layer, to form a bifunctional TSA membrane. The membrane exhibits excellent oil/water separation performance, and efficient photodegradation of solubilized methylene blue under ultraviolet irradiation. The membrane also exhibits excellent stability and durability, with a water contact angle of > 150°, and a high separation efficiency after 10 consecutive cycles. The membrane therefore has potential in sewage and wastewater treatment.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Yan Yang,Zhijie Zhang,Yali He,Zhihua Wang,Yanbao Zhao,Lei Sun
In order to develop a novel method for bacteria detection, Ag@TiO 2 electrospinning Nanofibrous felts have been fabricated by in situ decoration of size tunable Ag nanoparticles on anatase TiO 2 nanofibers. The morphologies and structures of the as-prepared Ag@TiO 2 electrospinning nanofibrous felts were characterized by techniques of scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The result show that Ag NPs were uniformly deposited on the surfaces of TiO 2 nanofibers, especially when the deposition time in Tollens’ reagent was 10 min. The free-standing composite nanofibrous felts processes superb performance of surface enhanced Raman scattering, which was demonstrated by small probe mecules of 4-mercaptobenzoic acid and 4-mercaptophenol, and the lowest detection limit was near to10 −9 mol/L. More importantly, the as-fabricated Ag@TiO 2 nanofibrous felts as SERS substrate can detect biomacromolecules such as bacteria of Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) directly without previous bacteria-aptamer conjugation as the traditonal process. In addition, the composite nanofibrous felts also show outstanding antimicrobial activities against both Gram-negative of E. coli and Gram-positive of S. aureus , evaluated by method of absorption and microscopic observation. The results show that the bacteriostasis rate is reached to 99%, especially significant for E. coli . The free-standing, high porous, and flexible substrate of Ag@TiO 2 electrospun nanofibrous membranes have potential application in versatile fields such as microorganism sensors and water purifier.
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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2018
·
IF 4.514
Linlin Ren,Qiang Li,Jibao Lu,Xiaoliang Zeng,Rong Sun,Jianbo Wu,Jian-Bin Xu,Ching-Ping Wong
Polymer composites with high thermal conductivity have a great potential application in modern electronics, due to their light-weight, easy process, low cost and stable physical and chemical properties. Nevertheless, most polymer composites commonly possess unsatisfactory thermal conductivity, primarily because of the high interfacial thermal resistance between inorganic fillers. Herein, we report a novel method through silver-deposition on the surface of the fillers to create a silver nanoparticle “bridge”, to decrease the interfacial thermal resistance between fillers. The results demonstrate that the out-of-plane thermal conductivity of the epoxy resin/sphere alumina composites is increased to 1.304 W m −1 K −1 , representing an improvement of 624% compared with pure epoxy resin. This strategy provides an insight for the design of thermally conductive polymer composites with potential to be used in next-generation electronic packaging.
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Journal of Energy Storage
·
2018
·
IF 0
Yuan Wu,Guorong Chen,Zhuyi Wang,Yin Zhao,Liyi Shi,Jiefang Zhu,Meihong Zhang,Rongrong Jia,Shuai Yuan
Poor intrinsic electrical conductivity as well as considerable volume change during lithium alloying/dealloying process has been a critical defect for high theoretical capacity silicon-based anodes. In our work, we demonstrate the synthesis design of multiscale recombined dendritic Si/Ag/C anode for high energy density LIBs via compositing bulky silicon with uniformly distributed Ag NPs, followed by a carbon source PDA (polydopamine) coating step. Here Ag NPs are generated by an in situ redox reaction between Ag + and PDA, no need for additional reducing agents. According to the characterization analysis, the robust porous Si/Ag/C structure can provide channels for fast Li + diffusion and electron conduction, promoting the formation of a thinner and more stable SEI film. As a result, the Si/Ag/C composite anode still yields a relatively high residual capacity of 1422.1 mAh g −1 after 100 cycles at 0.2 A g −1 . In addition, it remains 633.1 mAh g −1 after 500 cycles at a high current density of 8 A g −1 .
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2018
·Vol. 2018
·期 24
·2835-2840
·
IF 2.507
Qijun Dai,Lu Li,Chungang Wang,Changli Lv,Zhongmin Su,Fang Chai
Graphical Thin films of Ag microflowers (MFs) were fabricated on substrates. SEM studies revealed that the Ag MFs are assembled from thin nanosheets composed of Ag nanoparticles. The potential of the film as a catalyst in the reduction of nitrophenols and as a substrate for surface-enhanced Raman scattering was investigated. Three-dimensional flowerlike Ag microstructures were assembled in situ on a substrate to fabricate Ag microflower (Ag MF) films. The morphology and size of the Ag MFs can be easily controlled by varying the reaction time. The mechanism of growth of Ag MFs was investigated by SEM. The shape evolution revealed that the Ag MFs are assembled from thin nanosheets composed of Ag nanoparticles (NPs), and the elemental composition of the NPs was evidenced by energy-dispersive X-ray spectroscopic analysis. The potential of the film as a catalyst in the reduction of nitrophenols was investigated. The reusability of the catalyst was estimated by recycling catalysis of 4-nitrophenol. Moreover, the Ag MF film could be used as a versatile substrate for surface-enhanced Raman scattering (SERS) for detection of Rhodamine 6G with a detection limit as low as 1 × 10 –7 m . The results demonstrated that the Ag MF film exhibits excellent SERS enhancement ability and catalytic activity.
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