MATERIALS AND MANUFACTURING PROCESSES
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2014
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IF 1.486
Quan Zhang,Fei Li,Xinyuan Chang,Deliang He
Photocatalytic activities of three composites, namely nickel foam/Ag-TiO2, nickel foam/Ag-ZnO, and nickel foam/Ag-WO3, were evaluated for toluene degradation in a home-made cuboid photoreactor. Scanning electron microscopy and energy dispersive spectrometry were employed to characterize these photocatalysts. The photodegradation effects of the three photocatalysts peaked under 60% relative humidity, with nickel foam/Ag-TiO2 exhibiting the highest rate of photocatalytic toluene degradation. Controlling humidity could enhance the photocatalytic toluene degradation activities of the three composites, which are significantly affected by a wider band gap. In this study, a dynamic model was proposed and analyzed according to the time-dependent photodegradation of toluene.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
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2014
·Vol. 16
·期 28
·14706-14712
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IF 4.198
Xuan He,Hui Wang,Zhongbo Li,Dong Chen,Qi Zhang
An efficient and green approach was used to fabricate novel and low-cost surface-enhanced Raman scattering (SERS) spectroscopy sensors based on 4-aminothiophenol (4-ATP) functionalized ZnO–Ag hybrid nanoflowers for the detection of explosives. Such SERS sensors exhibited high sensitivity to rhodamine 6G (R6G) at a low concentration of 10−12 M and an enhancement factor of over 4.12 × 106 was achieved. Moreover, the Raman-inactive trinitrotoluene (TNT) initiated the high Raman scattering of non-resonated 4-ATP through the formation of a π-donor–π-acceptor interaction between the π-acceptor, TNT, and the π-donor, the 4-ATP–Ag–ZnO complex, on the flower-like hybrids. Because this π-donor–π-acceptor interaction could effectively induce the “hot spots” for SERS, TNT concentrations as low as 5 × 10−9 M could be detected. Furthermore, other derivatives of TNT were also explored, and this sensor exhibited better selectivity for TNT than other similarly structured explosives. The low-cost hybrid SERS substrates presented good sensitivity and reproducibility for the analytes employed, demonstrating promising application in forensic science and homeland security.
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PubMed
高影响因子
RSC Advances
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2015
·Vol. 5
·期 15
·11349-11357
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IF 3.84
Yong Yang,Guozhong Wang,Gang Gu,Qian Li,Shenghong Kang,Yunxia Zhang,Dickon H. L. Ng,Huijun Zhao
A facile and economical one-pot microwave-assisted approach for the synthesis of Ag decorated yolk@shell structured TiO2 microspheres (Ag-TS) is reported. The rapid and uniform microwave heating could reduce the reaction time to 30 min, an order of magnitude shorter than that of conventional methods. The characterization data confirmed that the resultant mesoporous structured Ag-TS were highly uniform in size with an average diameter of ∼0.5 μm, which was constructed by small anatase TiO2 nanoparticles, along with Ag nanoparticles ranging from 10 to 50 nm homogeneously dispersed on the microspheres. Nitrogen adsorption–desorption measurement revealed that all the Ag-TS samples had high specific surface areas (>100 m2 g−1) and abundant mesoporous structures. The growth model of Ag-TS was proposed based on a series of contrast experiments, the unique selective heating of reaction solvent (deionized water and ethanol) by the microwave method was found to be critical. At the initial stage, amorphous solid microspheres were formed by heating of ethanol molecules through absorbing microwave energy due to the better microwave absorbing performance. Then water molecules were heated by the microwave irradiation, the crystallization of anatase TiO2 on the surface of the solid microspheres started, followed by the Ti species diffusing spontaneously towards the outer surface of the solid microspheres and leading to the formation of the outer shell due to the Ostwald ripening process. Finally, water continuously diffused through the outer shell and guided the subsequent crystallization of anatase TiO2, resulting in the formation of the core. Besides, the application of Ag-TS for the removal of water contaminants including toxic heavy metal hexavalent chromium (Cr(VI)) ions and organic dye methylene blue (MB) were also evaluated.
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RSC Advances
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2014
·Vol. 4
·期 105
·60460-60466
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IF 3.708
Shuxian Huang,Zuoyi Xiao,Shangru Zhai,Bin Zhai,Feng Zhang,Qingda An
To enhance the stability of a catalyst that uses alginate as a carrier, Ag nanoparticle-loaded glutaraldehyde-crosslinked calcium alginate (Ag/CA@GTA) hydrogel beads were prepared. The Ag/CA@GTA hydrogel beads were characterized by UV-visible spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy analyses. Given that the mechanical strength of the support was remarkably enhanced by crosslinking alginate with GTA, the resulting Ag/CA@GTA beads exhibited high stability and durable activity, with more than 97% conversion within 10 successive cycles, for the catalytic reduction of 4-nitrophenol to 4-aminophenol by NaBH4 in aqueous solution. These Ag/CA@GTA hydrogel beads were expected to have potential as a highly efficient, cost-effective and eco-friendly heterogeneous catalyst for industrial applications.
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RSC Advances
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2015
·Vol. 5
·期 110
·90457-90465
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IF 3.84
Shicai Xu,Jihua Wang,Yan Zou,Hanping Liu,Guiying Wang,Xiumei Zhang,Shouzhen Jiang,Zhen Li,Dongyan Cao,Rongxia Tang
An efficient surface enhanced Raman scattering (SERS) substrate of graphene-isolated Ag nanoparticle (G/AgNP) has been developed by using excimer laser to ablate the ordered pyrolytic graphite in high vacuum onto Ag nanoparticles. By combining the electromagnetic activity of AgNPs and unique physical/chemical properties of graphene, the G/AgNP substrates shows high performance in terms of sensitivity, signal-to-noise ratio and reproducibility. The average enhancement factor obtained from the G/AgNP substrates for rhodamine 6G probe molecules is over 108. The maximum deviations of SERS intensities from 20 positions of a same SERS substrate are in the range of 4.20% to 6.75% and from 20 different substrates in various batches are in the range of 4.43% to 7.71%, depending on different vibration modes. As a practical application of this SERS system, we detect the adenosine concentration in human serum. The detection results show a good linear correlation between SERS intensity and adenosine concentration within the range of 2 to 200 nM. This work may open up new opportunities in developing the applications of SERS in biomedical diagnostics, biological sensing and other biotechnology.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2015
·Vol. 132
·期 37
·
IF 1.768
Shan Li,Jianxin Xiong,Jingsong Shen,Yong Qin,Juan Li,Fuqiang Chu,Yong Kong,Linhong Deng
A novel electrochemical sensor based on Ag nanoparticles (AgNPs) decorated polyaniline/graphene composites (PANI/G) is developed, which can be used for sensitive determination of H 2 O 2 . For the construction of the H 2 O 2 sensor, polyaniline (PANI) is first electrodeposited on the surface of graphene (G) to form PANI/G, and then horseradish peroxidase (HRP) loaded on AgNPs (HRP/AgNPs) is immobilized on to the PANI/G. H 2 O 2 can be catalyzed by HRP to generate current response which can be significantly enhanced by AgNPs, and thus the PANI/G based sensor can be utilized for the detection of H 2 O 2 . Under the optimized conditions, the proposed H 2 O 2 sensor exhibits wide linear response to H 2 O 2 concentration ranging from 0.25 to 2.25 m M with a detection limit of 0.03 m M (signal-to-noise ratio of 3), and it also shows high selectivity and reproducibility. The method is simple and cost-effective, and can be a promising candidate as the sensitive sensing platform for H 2 O 2 . © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42409.
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ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Dong-Fang Li,Jin-Chuan Mao,De-Li Chen,Fang Chen,Hong Ze-Wen,Xiao-Yi Zhou,Ya-Hao Wang,Xiao-Shun Zhou,Zhen-Jiang Niu,Emmanuel Maisonhaute
The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-to-contact STM-break junction. All single-molecule junctions present three sets of conductance values revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes. Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes, respectively. The present study therefore shows that nitrile and amino groups can also be used as effective anchors for other metals than gold.
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-4
·
IF 5.578
Yin Yongqi,Sun Ye,Yu Miao,Liu Xiao,Jiang Tingting,Yang Bin,Liu Danqing,Liu Shaoqin,Cao Wenwu
ZnO nanorods (NRs) are known for ultra-sensitive biomolecule detection through fluorescence enhancement. In this work, we demonstrate that ZnO NR arrays grown on Ag layers can significantly improve the enhancement up to 86 times compared to that grown on bare Si and the enhancement can be modified in a controlled manner by varying Ag thickness. The much improved waveguide properties are attributed to the high reflectance of the Ag layers and their tuning effect on the diameters of ZnO NRs. Our results provide a deep insight into the mechanism of NRs-based fluorescence enhancement platform.
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MATERIALS CHEMISTRY AND PHYSICS
·
2015
·
IF 2.259
Yang Li,Taotao Wu,Mujie Yang
Nanocomposites of quaternized and crosslinked poly(4-vinylpyridine) (QC-P4VP) and silver nanoparticles were prepared by a two-step procedure, and characterized by Fourier-transform infrared spectroscopy, Ultraviolet–visible spectroscopy and scanning electron microscopy. Bilayer-structured humidity sensors based on the nanocomposites were fabricated, and the effects of the concentration of silver salt precursor and poly(4-vinylpyridine), the method for the reduction of silver salt, the deposition order of the sensitive layers and environmental temperature on the humidity sensing characteristics of the composite sensor have been examined at room temperature. The composite sensor exhibited low impedance under dry atmosphere due to the introduction of Ag nanoparticles, and could detect very low relative humidity (RH) (down to 1% RH) with good sensitivity (impedance change of 2000% from 1% to 30% RH). In addition, the composite sensor demonstrated very wide measuring range (1–98% RH), and revealed faster response and smaller hysteresis than the sensor based on QC-P4VP alone. The complex impedance spectra of the composite sensor in the environments with different RH levels were investigated to explore its humidity sensing mechanism.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Zhengyi Zhang,Jiajie Yu,Jingying Yang,Xiang Lv,Tianhe Wang
Porous Ag/TiO 2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO 2 films. The highest SERS sensitivity that allowed as low as 10 −10 M aqueous CV to be detected, was achieved with the PEG/(C 4 H 9 O) 4 Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10 −10 to 10 −5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO 2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Yao Yao,Mingli Yin,Junqing Yan,Dong Yang,Shengzhong (Frank) Liu
Ag-WO 3 core-shell nanospheres (CSNSs) are fabricated for gas sensor applications. It is found that the sensor based on Ag-WO 3 CSNSs dramatically improve the sensor performance towards alcohol vapor, with significantly lower optimum working temperature (260 °C) and superior detection limit (0.20 ppm) comparing to pure WO 3 hollow nanospheres (HNSs). The Ag-WO 3 sensor displays an ultrahigh sensitivity under visible light illumination. When illuminated under a 150 W xenon arc light source, the response is increased from 62 to 160, the optimum working temperature is reduced from 260 to 190 °C, and the detection limit is improved from 0.20 to 0.032 ppm. This work may offer an attractive strategy to improve sensitivity of light-enhanced plasmonic metal-oxide based gas sensors.
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CHEMICAL PAPERS
·
2024
·
IF 2.1
Wei Zijie,Jiang Cuifeng,Chen Xinyan,Li Hui,Song Juan
In this study, Os/Ag nanoparticles (Os/Ag NPs) with smaller K m and almost five times V max compared to Os NPs were prepared. This not only reduced the cost of nanozyme, but also improved the catalytic ability. Addition of L-Cysteine or glutathione (GSH) resulted in inhibitory effect on the peroxidase-like activity of Os/Ag nanozyme. Therefore, the L-Cysteine and GSH could be detected by absorption spectra method with limit of detection (LOD) of 0.22 μM and 0.2 μM, respectively. Moreover, a colorimetric sensing system for L-Cysteine and GSH based on portable paper strip and smartphone was fabricated with LOD of 1.72 μM and 1.4 μM, respectively. Furthermore, this method can be used in fetal bovine serum with recovery rates ranging from 89.42% to 109.0%. The sensing system exhibited good selectivity. This proposed colorimetric sensing assay holds great potential application in the detection of biothiols when no sophisticated equipment are available. Graphical abstract
Scheme illustration for the colorimetric detection of L-Cysteine and GSH by use of smartphone
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