查找使用阿拉丁产品的科研文献

Fabrication and Sintering Behavior of Nano Cu–Ag Composite Paste for High-Power Device

Weishan Lv,Jiaxin Liu,Yun Mou,Yongjie Ding,Mingxiang Chen,Fulong Zhu

Silica Coated Upconversion Nanoplatform for Ag-Based Chemo-/Photodynamic Therapy against Drug-Resistant Bacteria

Yuxian Su,Yingyan Mao,Shen Wu,Li Liu,Shipeng Wen

Near-infrared (NIR) driven photodynamic therapy based on upconversion luminescent nanoparticles (UCNPs) is promising for fighting drug-resistant bacteria infections in deep tissues due to its good noninvasive, nonspecific, and non-drug-resistant properties, but is greatly limited by its low efficacy. Herein, honeycomb-silica-coated upconversion nanoparticles (UCNP@mSiO2) with a size of less than 100 nm were successfully prepared by a typical silica sol–gel reaction assisted with an expanding agent (p-xylene). The honeycomb silica shell has large pores with an average diameter of about 10 nm and large pore volume of 0.82 cm3/g and exhibits a MC540 loading as high as 9% in weight. The UCNP nanoparticle core can effectively capture NIR photons and activate the merocyanine 540 photosensitizer (MC540), generating reactive oxygen species to kill the drug-resistant bacteria of deep tissues. To avoid the drug prerelease, Ag nanoparticles in diameter close to that of the silica hole were covalently grafted onto the aminated UCNP@MC540@mSiO2 (UMS-NH2) nanoparticle. The Ag-decorated UMS-NH2 nanoparticles (UMSAg) showed synergistic antibacterial effects of Ag chemotherapy and photodynamic therapy and are more stable than undecorated UMS nanoparticles in an aqueous medium. The UMSAg with unreacted amino groups enhanced the binding of Ag to the bacterial membrane, effectively exerting the antibacterial effect of Ag+ and ROS. In in vitro antibacterial experiments, the killing rates of the UMSAg composite (150 μg/mL) against drug-resistant Staphylococcus aureus and drug-resistant Pseudomonas aeruginosa under NIR irradiation were 100% and 99.6%, respectively. In addition, the antibacterial activity of the UMSAg group was significantly higher than that of the sole Ag nanoparticles without irradiation. This work provides good insight for the design of efficient antibacterial agents and has a potential application for the bacterial infection of deep tissues.

Coordination-Driven One-Step Rapid Self-Assembly Synthesis of Dual-Functional Ag@Pt Nanozyme

Zaihui Du,Longjiao Zhu,Pengfei Wang,Xinyue Lan,Shenghao Lin,Wentao Xu

Realizing high-precise and adjustable regulation of engineering nanozyme is important in nanotechnology. Here, Ag@Pt nanozymes with excellent peroxidase-like and antibacterial effects are designed and synthesized by nucleic acid and metal ions coordination-driven one-step rapid self-assembly. The adjustable NA-Ag@Pt nanozyme is synthesized within 4 min using single-stranded nucleic acid as templates, and peroxidase-like enhancing FNA-Ag@Pt nanozyme is received by regulating functional nucleic acids (FNA) based on NA-Ag@Pt nanozyme. Both Ag@Pt nanozymes that are developed not only has simple and general synthesis approaches, but also can produce artificial precise adjustment and possess dual-functional. Moreover, when lead ion-specific aptamers as FNA are introduced to NA-Ag@Pt nanozyme, the Pb 2+ aptasensor is successfully constructed by increasing electron conversion efficiency and improving the specificity of nanozyme. In addition, both nanozyme has good antibacterial properties, with ~100% and ~85% antibacterial efficiency against Escherichia coli and Staphylococcus aureus , respectively. This work provides a synthesis method of novelty dual-functional Ag@Pt nanozymes and successful application in metal ions detection and antibacterial agents.

Increasing hotspots density for high-sensitivity SERS detection by assembling array of Ag nanocubes

Jiaqi Liu,Zhongshun Wang,Ya'nan Meng,Chunning Chen,Qiye Chen,Yalei Wang,Shuzhen Dou,Xiaoyang Liu,Nan Lu

Trace analysis has great promise in the fields of disease diagnosis and environment protection. Surface-enhanced Raman scattering (SERS) has wide range of utilization due to its reliable fingerprint detection. However, the sensitivity of SERS still needs to be enhanced. Raman scattering of target molecules around hotspots, the area with extremely strong electromagnetic field , can be highly amplified. Therefore, to increase the density of hotspots is one of the major approaches for enhancing the detection sensitivity of target molecules. In this paper, an ordered array of Ag nanocubes was assembled on a thiol modified silicon substrate as a SERS substrate, which provided high-density hotspots. The detection sensitivity is demonstrated by the limit of detection, which is down to 10 −6  nM with Rhodamine 6G as probe molecule. The wide linear range (10 −7 –10 −13  M) and low relative standard deviation (<6.48%) indicate the good reproducibility of the substrate. Furthermore, the substrate can be used for the detection of dye molecules in lake water. This method provides an approach for increasing hotspots of SERS substrate, which could be a promising method to achieve good reproducibility and high sensitivity.

Improved Simulated-Daylight Photodynamic Therapy and Possible Mechanism of Ag-Modified TiO2 on Melanoma

Jing Xin,Jing Wang,Yuanping Yao,Sijia Wang,Zhenxi Zhang,Cuiping Yao

Simulated-daylight photodynamic therapy (SD-PDT) may be an efficacious strategy for treating melanoma because it can overcome the severe stinging pain, erythema, and edema experienced during conventional PDT. However, the poor daylight response of existing common photosensitizers leads to unsatisfactory anti-tumor therapeutic effects and limits the development of daylight PDT. Hence, in this study, we utilized Ag nanoparticles to adjust the daylight response of TiO2, acquire efficient photochemical activity, and then enhance the anti-tumor therapeutic effect of SD-PDT on melanoma. The synthesized Ag-doped TiO2showed an optimal enhanced effect compared to Ag-core TiO2. Doping Ag into TiO2produced a new shallow acceptor impurity level in the energy band structure, which expanded optical absorption in the range of 400–800 nm, and finally improved the photodamage effect of TiO2under SD irradiation. Plasmonic near-field distributions were enhanced due to the high refractive index of TiO2at the Ag-TiO2interface, and then the amount of light captured by TiO2was increased to induce the enhanced SD-PDT effect of Ag-core TiO2. Hence, Ag could effectively improve the photochemical activity and SD-PDT effect of TiO2through the change in the energy band structure. Generally, Ag-doped TiO2is a promising photosensitizer agent for treating melanoma via SD-PDT.Keywords:melanoma;simulated-daylight photodynamic therapy;Ag-doped TiO2;Ag-core TiO2

Enhanced photocatalytic ammonia oxidation activity and nitrogen selectivity over Ag/AgCl/N-TiO2 photocatalyst

Jiaojiao Guan,Daorong Li,Jiahui Feng,Peng Xu,Zhaonian Li,Siqi Ge,Hongxia Chen,Kunfeng Zhang

The removal of ammonia (NH 3 ) emitted from agricultural and industrial activities is of great significance to protect human health and ecological environment. Photocatalytic NH 3 oxidation to N 2 under mild conditions is a promising strategy. However, developing visible light photocatalysts for NH 3 oxidation is still in its infancy. Here, we fabricate N-TiO 2 and Ag/AgCl/N-TiO 2 photocatalysts by sol-gel and photodeposition methods, respectively. The introduction of N not only endows TiO 2 with visible light response (absorption edge at 460 nm) but also results in the formation of heterophase junction (anatase and rutile). Thus, N-TiO 2 shows 2.0 and 1.8 times higher than those over anatase TiO 2 and commercial TiO 2 for NH 3 oxidation under full spectrum irradiation. Meanwhile, surface modification of Ag can simultaneously enhance visible light absorption (generating localized surface plasmon resonance effect) and charge separation efficiency. Therefore, the photocatalytic activity of Ag/AgCl/N-TiO 2 is further improved. Furthermore, the presence of N and Ag also enhances the selectivity of N 2 product owing to the change of reaction pathway. This work simultaneously regulates photocatalytic conversion efficiency and product selectivity, providing some guidance for developing highly efficient photocatalysts for NH 3 elimination.

Dielectric properties of a linear polymer-matrix composite filled with aligned Ag@BaTiO3 flakes

Gang Jian,Liang Feng,Yuhang Du,Ning Yang,Shangtao Zhu,Rui Dong,Yong Jiao

Composites with linear dielectric properties possess advantages in energy storage fields for the high charge-discharge efficiency with low energy loss. However, energy density of them is limited due to low permittivity. Here, a linear dielectric polydimethylsiloxane (PDMS) composite filled with parallel aligned core-shell Ag@BaTiO 3 (BT) 2D flakes is prepared by directional shearing, which possesses high permittivity and excellent energy storage properties. Compared with traditional polymer/core-shell hybrid filler composites, this work presents modified filler composition, different filler dimension and enhanced energy storage performances. Conformably-coated Ag@BT flakes are prepared through simultaneous hydrolysis on polyvinylpyrrolidone-functionalized Ag flakes, forming a smooth ∼100 nm thick coating layer. The aligned PDMS/40 vol% Ag@BT flake composite exhibits a very high permittivity of 347 and a low dielectric loss< 0.03 at 100 Hz from 20 to 150 °C. The comp°site exhibits an enhanced breakdown strength of 26 kV cm −1 owing to BT coverage-shell blocking and parallel filler arrangement, compared with that of percolative composites filled with metal particles without shell-coverage. The composite exhibits linear dielectric characteristics with high discharged energy density of 6.18 × 10 −3 J cm −3 and superhigh charge-discharge efficiency> 95% at 20 kV cm −1 . This study demonstrates Ag@BT flake based linear-polymer composites for energy related applications.

Extending Ag Nanoparticles as Colorimetric Sensor to Industrial Zinc Electrolyte for Cobalt Ion Detection

Ni Xiao,Wei Weng,Ding Tang,Wen Tan,Liye Zhang,Zheyuan Deng,Xiaopeng Chi,Jiangang Ku,Shuiping Zhong

The direct and rapid determination of trace cobalt ion (Co2+) in the electrolyte of zinc smelting plants is urgently needed but is impeded by the severe interference of extremely high-concentration zinc ions in the solution. Herein, colorimetric detection of Co2+by the polyvinylpyrrolidone functionalized silver nanoparticles (PVP-AgNPs) is realized in solutions with the Zn/Co ratio being high, up to (0.8–5) × 104, which is located within the ratio range in industrial solution. The high concentration of Zn2+induces a strong attenuation of Co2+-related signals in ultraviolet-visible (UV-vis) extinction spectra; nevertheless, a good linear range for detecting 1–6 mg/L Co2+in 50 g/L Zn2+solution is still acquired. The strong anti-interference toward other metal ions and the mechanism understanding for trace Co2+detection in such a high-concentration Zn2+solution are also revealed by systematic analysis techniques. The results extend the AgNPs as colorimetric sensors to industrial solutions, providing a new strategy for detecting trace-metal ions in industrial plants.Keywords:colorimetric detection;silver nanoparticles;polyvinylpyrrolidone;trace Co2+determination;industrial high-concentration zinc solution

MoS2/Au/Ag Nanostructures for Ratiometric Surface-Enhanced Raman Scattering Determination of Pesticide Residues

Xingxing Yu,Yan Sun,Jieyu Hu,Junjie Wang,Xiumei Zhuang,Shenghao Zhang,Haiting Ren,Hongxing Qiu,Yueshou Zhang,Yongjun Hu

Surface-enhanced Raman scattering (SERS) is a promising method for rapid and sensitive detection of pesticide residues. Herein, a three-dimensional MoS2/Au/Ag nanostructure was developed by employing composite systems containing semiconductors, noble metal nanoparticles, and internal standard. The MoS2 nanoflowers provide abundant anchors for the loading of plasmonic nanoparticles so as to generate intense electromagnetic “hot spots,” and the Au-MBN/Ag nanostructures can increase the accuracy of SERS detection with the calibration ability of the internal standard molecules (4-mercaptobenzonitrile, 4-MBN). Therefore, the MoS2/Au/Ag nanostructures integrate the advantages of high-enhancement SERS substrates and high-accuracy ratiometric Raman detection. Moreover, the nanostructures were fabricated via a facile procedure and showed high sensitivity, accuracy, and reproducibility in SERS detection. The nanostructures also showed good linear fitting between the ratios of Raman intensity and logarithmic concentrations of analytes in ratiometric SERS analysis. In addition, thiabendazole (TBZ) in apple juice was successfully detected by using the as-prepared SERS substrates with a limit of detection down to 0.1 ppm in practical applications. To conclude, the MoS2/Au/Ag nanostructures showed excellent SERS activity in ratiometric analysis and the substrate is expected to have great potential for the quantitative detection of low-concentration pesticide residues.

Facile fabrication of bimetallic Cu–Ag binary hybrid nanoparticles and their application in catalysis

Yuxi Meng,Hanyu Gao,Shuang Li,Fang Chai,Lihua Chen

Herein, high efficiency and recyclable Cu–Ag hybrid catalyst (Trp–Cu–Ag) NPs were prepared by the hydrothermal method using L-tryptophan as a reducing agent and protecting reagent. The structure, morphology and catalytic properties of the Trp–Cu–Ag NPs were investigated in detail. The binary Trp–Cu–Ag NPs were assembled using Trp–Cu nanosheets and Ag nanoparticles through a one-step process. The developed Trp–Cu–Ag NPs show excellent catalytic performance in the reduction of nitrophenols (4-nitrophenol, 2-nitrophenol and 3-nitrophenol). Meanwhile, the Trp–Cu–Ag NPs exhibited a stable conversion efficiency of over 95% for more than 10 recycles in the reduction of 4-nitrophenol. The binary Trp–Cu–Ag NPs can also catalytically reduce K3(Fe(CN)6) in the presence of a NaBH4 aqueous solution with high efficiency. All in all, the obtained Trp–Cu–Ag NPs show potential as a catalyst in practical environmental protection applications due to their cost-effective and recyclable features.

Size dependent SERS activity of Ag triangular nanoplates on different substrates: Glass vs paper

Guojun Weng,Yao Feng,Jing Zhao,Jianjun Li,Jian Zhu,Junwu Zhao

Ag triangular nanoplates have been widely used as the SERS substrate due to their anisotropic morphology and sharp corners. In this work, SERS activity of Ag triangular nanoplates on glass and paper substrates was investigated with different concentration and size. A tiny triangular nuclei based synthesis method was employed to produce Ag triangular nanoplates with different size. And the extinction coefficients of Ag triangular nanoplates with different size were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and transmission electron microscopy (TEM). With definite concentration, Ag triangular nanoplates with small size showed stronger SERS intensity on glass substrate at high concentrations, while large Ag triangular nanoplates exhibited better SERS effect on paper substrate at low concentrations. The possible reasons for distinct SERS activity of Ag triangular nanoplates on glass and paper were discussed with scanning electron microscope (SEM) characterization. These results exhibited important implications for fabricating Raman substrates using Ag triangular nanoplates and could be applied to the SERS sensing with flexile substrate.

Enhancement in photocatalytic performance of Ag–AgCl decorated with h-WO3 and mechanism insight

Chai Chen,Liu Jianxin,Wang Yawen,Zhang Xiaochao,Duan Donghong,Fan Caimei,Wang Yunfang

A h-WO 3 decorated Ag–AgCl composite was prepared through facile precipitation and photoreduction methods and demonstrated to be a highly efficient and stable photocatalyst for the degradation of Rhodamine B (RhB) under visible light. Ag–AgCl/h-WO 3 exhibited much improved photocatalytic performance was elucidated from the physical–chemical properties of AgCl and h-WO 3 and the surface plasmon resonance effect of the Ag particles. The techniques of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectrometry (XPS) and photocurrent were used to characterize crystalline phases, morphology, composition and separation efficiency between electrons (e − ) and holes (h + ) of the synthesized composite photocatalyst. XPS results confirmed the existence of W 5+ and W 6+ on the surface of h-WO 3 sample, which favored electrons transfer between AgCl and Ag, and generated superoxide radical for the degradation of RhB. The active species trapping experiments results further demonstrated that the formation of superoxide radical during the system. Finally, the underlying photocatalytic mechanism for the removal of RhB by Ag–AgCl/h-WO 3 composite was examined.