SENSORS AND ACTUATORS B-CHEMICAL
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2016
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IF 4.758
Jian Zhu,Jing-Fei Wang,Jian-Jun Li,Jun-Wu Zhao
Gold-silver bimetallic fluorescence quenching nanoprobe has been synthesized based on the gold triangular nanoplate with silver coating. In order to guarantee the specificity of the probe, surface modifications of the triangular nanoplates including carboxyl replacement, carboxyl activation and antibody connection have been carried out. The fluorescence spectral study indicates that the fluorescence intensity of carcinoembryonic antigen (CEA) could be effectively quenched by the silver coated-gold triangular nanoprobe. And the fluorescence quenching ability could be improved by optimizing the interaction time and amount of binding anti-CEA to modified nanoprobe, and the interaction time of binding CEA to anti-CEA. By using this sensing method, the CEA could be detected with an ultra low detection limit of 10 pg/mL, and the linear range spans a scope from 20 to 200 pg/mL. Interference experiment results show that the influence from the interfering proteins could be neglected in the detection procedure. And the CEA could be specifically detected by using this bimetallic triangular nanoplate probe.
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2017
·Vol. 33
·期 6
·946-950
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IF 1.024
Ji Ye,Han Tianyi,Zhang Yong,Wang Ziying,Zhang Tong,Leng Jiyan
Ag nanocubes-reduced graphene oxide(AgNCs-rGO) nanocomposite was successfully prepared by an in situ synthesis method, in which AgNCs were loaded onto the surface of rGO during the formation of AgNCs in an ethylene glycol solution. Characterization by X-ray diffraction, UV-Vis spectroscopy, and scanning electron microscopy indicated the successful preparation of the AgNCs-rGO nanocomposite. Most importantly, the AgNCs-rGO nanocomposite exhibited excellent electrocatalytic activity for the reduction of H 2 O 2 , leading to a high-performance non-enzymatic H 2 O 2 sensor with a linear detection range and detection limit of approximately 0.1 mmol/L to 70 mmol/L( r =0.999) and 0.58 μmol/L, respectively. Our present work provides a new and highly efficient method for fabricating high-performance electrochemical sensors.
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APPLIED THERMAL ENGINEERING
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2017
·
IF 3.444
Haoran Li,Yurong He,Ziyu Liu,Yimin Huang,Baocheng Jiang
Research in collection and conversion of solar energy has attracted an increasing interest because of the fact that conventional energy resources are becoming increasingly exhausted. For this reason, Ag@TiO 2 core–shell nanoparticles (NPs) with great absorptivity in the visible region were synthesized in this work. Subsequently, an experimental study on photo-thermal performances including steam generation and solar energy capture in a thermal receiver containing the Ag@TiO 2 NPs-based nanofluids was conducted. The effects of the NP concentration as well as the optical concentration were taken into consideration. The results showed that the nanofluids can be used for direct steam generation with a short period of solar irradiation time, even at the illumination intensity of 1 sun (1 sun = 1 kW/m 2 ). An evaporation efficiency of 53.6% can be achieved when the NP concentration is only 200 ppm owing to local heating induced by the surface plasmon resonance of the NPs. In addition, it is found that the nanofluid with a lower NP concentration has a higher temperature rise during illumination. Our findings also showed that the absorbed solar energy is transferred preferentially into latent heat enthalpy and consumed for steam generation instead of heating the nanofluids.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2017
·
IF 6.216
Ying Liu,Jijie Kong,Julong Yuan,Wei Zhao,Xin Zhu,Cheng Sun,Jimin Xie
A novel ternary Ag/Ag 2 CO 3 /BiVO 4 plasmonic heterojunction photocatalyst was successfully fabricated by a precipitation method over BiVO 4 , followed by light reduction. The obtained composites were characterized by various measurements and the photocatalytic performances of the as-prepared composites were assessed by the degradation of tetracycline (TC) under visible-light illumination. The ternary plasmonic heterojunction photocatalyst exhibits higher and wider absorption in the visible and ultraviolet regions than the pure BiVO 4 and it displays superior performance in the degradation of tetracycline. The highest efficiency of Ag/Ag 2 CO 3 /BiVO 4 photocatalyst to degrade TC is up to 94.9% at 150 min. On the basis of the obtained experimental results, the probable photocatalytic mechanism of the enhanced activity is discussed. The degradation of tetracycline is not only influenced by OH, but also caused by valence-band holes (h + ). Therefore, the improved photocatalytic activity of Ag/Ag 2 CO 3 /BiVO 4 is due to the enhanced absorbance under the visible light, the facilitated charge transfer and the inhibited recombination of electron-hole pairs. The likely degradation pathway was proposed on the basis of the intermediate products detected by GC–MS. Moreover, the surface plasmon resonance and the electric field enhancement were simulated by the three dimensional finite difference time domain (FDTD) method.
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高影响因子
JOURNAL OF POWER SOURCES
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2017
·
IF 6.395
Tao Fu,Jianxing Huang,Shaobo Lai,Size Zhang,Jun Fang,Jinbao Zhao
The catalytic activity and stability of electrocatalyst is critical for the commercialization of fuel cells, and recent reports reveal the great potential of the hollow structures with Pt skin coat for developing high-powered electrocatalysts due to their highly efficient utilization of the Pt atoms. Here, we provide a novel strategy to prepare the Pt skin coated hollow Ag-Pt structure (Ag-Pt@Pt) of ∼8 nm size at room temperature . As loaded on the graphene, the Ag-Pt@Pt exhibits a remarkable mass activity of 0.864 A/mg Pt (at 0.9 V, vs. reversible hydrogen electrode (RHE)) towards oxygen reduction reaction (ORR), which is 5.30 times of the commercial Pt/C catalyst, and the Ag-Pt@Pt also shows a better stability during the ORR catalytic process. The mechanism of this significant enhancement can be attributed to the higher Pt utilization and the unique Pt on Ag-Pt surface structure, which is confirmed by the density functional theory (DFT) calculations and other characterization methods. In conclusion, this original work offers a low-cost and environment-friendly method to prepare a high active electrocatalyst with cheaper price, and this work also discloses the correlation between surface structures and ORR catalytic activity for the hollow structures with Pt skin coat, which can be instructive for designing novel advanced electrocatalysts for fuel cells.
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RSC Advances
·
2016
·Vol. 6
·期 42
·35216-35227
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IF 3.289
Minmin Liu,Li-an Hou,Qi Li,Xiaojun Hu,Shuili Yu
Magnetic catalysts (Ag/AgCl/(x)FeX) were fabricated via a facile hydrothermal method followed by a precipitation–photo-reduction method. The Ag/AgCl/(x)FeX catalysts were applied to activate persulfate (PS) for tetracycline (TC) degradation. The degradation efficiencies of the Ag/AgCl/(x)FeX–PS system for TC removal were high due to the enhanced adsorptive capacity of (x)FeX, extended absorbance in the visible-light region and improved space separation of photo-induced charge carriers. The Ag/AgCl/(0.05)FeX catalyst exhibited better performance for TC removal compared with the other samples and complete degradation of TC could be achieved in 120 min by using 1 g L−1 Ag/AgCl/(0.05)FeX and 5.0 mM PS at pH 3.5. The characterization of the catalysts and Electron Paramagnetic Resonance (EPR) studies indicated that TC was mainly degraded by surface-adsorbed radicals resulting from the reaction between PS and Fe(II) on the catalysts under visible light. The Ag/AgCl/(x)FeX–PS system provides new insights for contaminant removal from water.
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RSC Advances
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2016
·Vol. 6
·期 37
·30852-30861
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IF 3.289
Fu Yang,Saifu Long,Shijian Zhou,Xiaoming Li,Xianfeng Liu,Shuying Gao,Yan Kong
A dispersed and stable catalytic active phase and a protective reaction environment are acknowledged as ideal metal catalyst characteristics. In this paper, a cores@shell structure of microreactor with a well-dispersed active phase of multiple free-Ag-cores, hollow cavity and protective mesoporous shell was prepared by a simple and novel construction approach. The organic ligand of aminosilane (APTES) was directly incorporated on carbon nanospheres to anchor Ag ions as a metallotemplate, which avoids the tedious steps of conventional methods, and then the sacrificed metallotemplate was employed for directly fabricating the special hollow mesoporous silica microreactors. As a result, multiple free active Ag-cores were in situ produced and encapsulated in the cavity of hollow mesoporous silica during the thermal process. The important evidence of the configuration including a big hollow cavity containing active multiple-Ag nanoparticles and a mesoporous SiO2-shell can be demonstrated with efficient techniques including XRD, FT-IR, XPS, BET, SEM and TEM. Just as expected, the catalyst as a functional microreactor exhibited a high catalytic activity for the liquid-reduction of 4-nitrophenol, and the increasing dosage of used catalyst contributes to the enhancing of catalytic activity. The methodology demonstrated here provides a new insight for the fabrication of versatile functional nanomaterials with noble or transition metals inside a hollow shell.
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Nanoscale
·
2016
·Vol. 9
·期 2
·899-906
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IF 7.76
Linxu Xu,Fang Cui,Jiajia Zhang,Yanjun Hao,Yan Wang,Tieyu Cui
Herein, an autocatalytic route to fabricate dual metal ion-equipped organic/inorganic hybrid silica, an ideal precursor for multifunctional silica-based composites integrated with well-dispersed Ag and Co3O4 nanoparticles was demonstrated. Significantly, by rational selection of reactants, such dual metal ion-equipped organic/inorganic hybrid silica can be synthesized through successive spontaneous reactions under near neutral conditions without an additional catalyst. Both the Ag+ and Co2+ ions are introduced into silica by chemical bonds, which favor the formation of small-sized and well-dispersed Ag and Co3O4 nanoparticles without aggregation in the entire silica matrix. After calcination, multifunctional silica composites equipped with well-dispersed Ag and Co3O4 nanoparticles were obtained. The as-obtained silica composites, as indicated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), have a spherical morphology and smooth surface. TEM tests also reveal the well dispersed fashion of Ag and Co3O4 nanoparticles. In addition, the obtained Ag–Co3O4@SiO2 composites exhibit good catalytic performance in the reduction of methylene blue (MB) with NaBH4 as a reducing agent, and can be readily recycled by an external magnetic field due to their superparamagnetic properties.
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高影响因子
BIOSENSORS & BIOELECTRONICS
·
2016
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IF 7.476
Hang Ao,Zhaosheng Qian,Yuyu Zhu,Meizhi Zhao,Cong Tang,Yuanyuan Huang,Hui Feng,Aijun Wang
Due to the vital role of tyrosinase in melanin biosynthesis and its function as an important biomarker for melanoma cancer, highly sensitive detection of its activity using biocompatible materials is in urgent demand. Herein we report a convenient and highly sensitive fluorometric biosensor for tyrosinase activity detection based on biocompatible dopamine-functionalized Au/Ag nanoclusters (Dopa-Au/Ag NCs). Dopamine with redox property was covalently linked to Au/Ag NCs surface and formed a Dopa-Au/Ag NCs bioconjugate with strong blue fluorescence. Dopamine is readily oxidized by molecular oxygen under the catalysis of tyrosinase. After dopamine is transformed to o -dopaquinone, an intraparticle photoinduced election transfer (PET) process occurs between Au/Ag NCs and o -dopaquinone moiety, leading to the fluorescence quenching of the Dopa-Au/Ag NCs bioconjugate. Thus, this biosensor was utilized for sensitive and selective detection of tyrosinase in terms of the relationship between fluorescence quenching efficiency and tyrosinase activity. This study discovers that Au/Ag NCs and dopaquinone can serve as a good electron acceptor and donor pair which results in an efficient intraparticle photoinduced electron transfer process, and also provides another alternative way for tyrosinase activity monitoring.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 66
·61109-61118
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IF 3.289
Baowen Sun,Chunsheng Wang,Shuhua Han,Yongfeng Hu,Lijuan Zhang
A silver nanocube (Ag NC) nanoparticle-enhanced fluorescent nanocomposite was developed. The designed nanocomposite contained an Ag NC core of 50 nm in size as enhancer, the 10 nm silica interlayer, and outer shell-periodic mesoporous organosilicas (PMOs) which incorporated the bis(rhodamine Schiff-base derivative) siloxane groups. Little fluorescence emission of nanocomposites was observed due to the existence of spirolactam in the rhodamine derivative, however, upon the addition of Cu2+, the fluorescence emission intensity increased dramatically, which resulted from ring-opening of the spirolactam in the rhodamine moieties. We showed the effect of using an Ag NC core on the fluorescence emission intensity of the novel system. The emission intensity was approximately 3-fold higher for Ag-nanocube@SiO2@PMOs than the control sample prepared by etching the silver core away with iodide. Moreover, the metal-enhanced fluorescence (MEF) mechanism in this system was investigated through measuring the fluorescence lifetime. In addition, the designed core–shell Ag-nanocube@SiO2@PMOs nanocomposite could act as a sensitive and selective sensor to detect the Cu2+, and we have been expecting that the detection limit would be reduced by reaping benefits from the plasmon resonance of Ag NC core in this nanocomposite system.
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RSC Advances
·
2016
·Vol. 6
·期 53
·47966-47973
·
IF 3.289
Yao Shi,Xiaoliang Zhang,Yongmei Zhu,Hongliang Tan,Xiangshu Chen,Zhang-Hui Lu
Ag–CeO2 nanocomposites (Ag@CeO2 NCs) with a core–shell structure have been successfully synthesized through the combination of a redox reaction and the reverse micelle technique without any additional reductants or surfactants. Under a N2 atmosphere, the redox reaction automatically occurs between Ag+ and Ce3+ in an alkaline solution, resulting in the formation of Ag@CeO2 NCs by the self-assembly process. By using the XRD, FE-SEM, TEM, XPS, and ICP methods, the characterized results of Ag@CeO2 NCs show that Ag nanoparticles (NPs) with a diameter of 3–7 nm are surrounded by CeO2 NPs. Compared to CeO2 supported Ag NPs, free Ag NPs, and CeO2, the as-synthesized Ag@CeO2 NCs exhibit a superior catalytic activity and high sustainability for the hydrogenation of 4-nitrophenol (C6H5NO3, 4-NP) and 2-nitroaniline (C6H6N2O2, 2-NA) with sodium borohydride (NaBH4) in water solution at room temperature. The Ag@CeO2 NCs can achieve a complete reduction of 4-NP and 2-NA with turnover frequencies (TOF) of 138.7 and 109.8 h−1, respectively. The durability tests show that the Ag@CeO2 NCs are still highly active for the reduction of 4-NP and 2-NA, preserving 98% and 95% of their initial catalytic activity even after ten runs.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2017
·
IF 2.536
Ru Li,Cuihua Lei,Xian-En Zhao,Yue Gao,Han Gao,Shuyun Zhu,Hua Wang
In this work, a label-free and sensitive fluorimetric method has been developed for the detections of biothiols including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), based on the specific biothiol-induced inhibition of the oxidase-like activity of silver ions (Ag + ). It is well established that o -phenylenediamine (OPD) can be oxidized by Ag + ions to generate fluorescent 2,3-diaminophenazine (OPDox). The introduction of biothiols would inhibit the oxidation of OPD by Ag + due to the strong coordination between biothiols and Ag + . The changes of fluorescence intensities obtained in the Ag + -OPD system exhibited good linear correlations in the ranges of 0.50–30.0 μM for Cys, 1.0–45.0 μM for Hcy and 0.50–40.0 μM for GSH. The detection limits (S/N = 3) of Cys, Hcy and GSH were 110 nM, 200 nM and 150 nM, respectively. Subsequently, the developed fluorimetric method was successfully applied for the detection of biothiols in human serum.
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