查找使用阿拉丁产品的科研文献

Revealing the Hemispherical Shielding Effect of SiO2@Ag Composite Nanospheres to Improve the Surface Enhanced Raman Scattering Performance

Fengyan Wang,Daxue Du,Shan Liu,Linna Wang,Tifeng Jiao,Zhaopeng Xu,Haiyan Wang

Many studies widely used SiO2@Ag composite nanospheres for surface enhanced Raman scattering (SERS), which mainly contributes to electromagnetic enhancement. In addition to experiments, previous simulations mostly adopted a two-dimensional model in SERS research, resulting in the three-dimensional information being folded and masked. In this paper, we adopted the three-dimensional model to simulate the electric field distribution of SiO2@Ag composite nanospheres. It is found that when the Ag nanoparticles are distributed densely on the surface of SiO2nanospheres, light cannot pass through the upper hemisphere due to the local surface plasmon resonance (LSPR) of the Ag nanoparticles, resulting in the upper hemisphere shielding effect; and if there are no Ag nanoparticles distributed densely on the surface of SiO2nanospheres, the strong LSPR cannot be formed, so the incident light will be guided downward through the whispering gallery mode of the spherical structure. At the same time, we designed relevant experiments to synthesize SiO2@Ag composite nanosphere as SERS substrate and used Rhodamine 6G as a probe molecule to study its SERS performance. This design achieved a significant SERS effect, and is very consistent with our simulation results.Keywords:SERS;LSPR;three-dimensional models;upper hemisphere shielding

Bi2MoO6/TiO2 heterojunction modified with Ag quantum dots: a novel photocatalyst for the efficient degradation of tetracycline hydrochloride

Zhuangzhuang Yin,Shihan Qi,Shangkun Deng,Kang Xu,Zhu Liu,Miao Zhang,Zhaoqi Sun

In this study, a Bi 2 MoO 6 /TiO 2 heterojunction photocatalyst modified with Ag quantum dots was successfully synthesized. The results demonstrated that Ag–Bi 2 MoO 6 /TiO 2 exhibited excellent photoelectrochemical performance and photocatalytic activity for the degradation of tetracycline hydrochloride. The catalyst had the best photocurrent density with a maximum value of 103.0 µA/cm 2 , which was 11.7 times higher than that of unmodified TiO 2 nanorods. Ag–Bi 2 MoO 6 /TiO 2 significantly increased the absorption intensity and red-shifted with a bandgap of 1.88 eV, which is substantially narrower than that of TiO 2 . Furthermore, it exhibited extremely high photocatalytic activity for the degradation of tetracycline hydrochloride with a degradation rate of 90.8% at 120 min. A photocatalytic mechanism was proposed to explain the principle of tetracycline hydrochloride degradation using this catalyst.

Improvement in the output performance of polyethylene oxide-based triboelectric nanogenerators by introducing core–shell Ag@SiO2 particles

Xu Liu,Xiao-Rong Sun,Chen Luo,Hong-Zhi Ma,Hua Yu,Yan Shao,Ming-Bo Yang,Bo Yin

The development of self-powered technology in nano-energy puts forward higher requirements for triboelectric nanogenerators (TENGs), in which it is necessary to further improve their output performance to broaden their scope of application, and environmentally friendly and sustainable development needs to be realized as well by the recycling of friction materials. The preparation of environmentally friendly and sustainable TENGs is reported in this work through a feasible and cost-effective solution casting method, in which polyethylene oxide (PEO) and Ecoflex were utilized as positive/negative friction materials, respectively. With introducing micron-sized core–shell Ag@SiO2 particles into the PEO matrix, micro–nano structures were constructed to increase the effective contact area, while the enhancement of dielectric properties was also achieved in the meantime. The Ag@SiO2–PEO/Ecoflex TENG with optimum particle content of 50 wt% produced a short-circuit current of 10 μA, an open-circuit voltage of 95 V, and a transfer charges of 35 nC at a frequency of 3 Hz. The maximum output power density of Ag@SiO2–PEO-50 wt%/Ecoflex TENG up to 1.5 W m−2 was reached under different load resistances. The stability and flexibility of TENGs were verified as well, which led to a novel approach for their application in wearable-flexible electronic devices. Additionally, the sustainable utilization of TENGs was achieved as a result of the water solubility of the PEO material, with significant output performance retention. This work provides an innovative approach for the further modification of the output performance of flexible and sustainable TENGs.

Multifunctional magnetic Fe3O4/GO/Ag composite microspheres for SERS detection and catalytic degradation of methylene blue and ciprofloxacin

Jiafeng He,Gao Song,Xinyue Wang,Ling Zhou,Jumei Li

It is greatly significant to remove organic dyes and antibiotics in water because they are extremely harmful for human health and environment. In this work, we successfully developed magnetic Fe 3 O 4 /GO/Ag composite microspheres, using Fe 3 O 4 microspheres as cores to wrap graphene oxide (GO) interlayer and further in situ depositing silver nanoparticles onto GO layer. The microspheres were characterized by SEM, XRD , XPS and Raman spectroscopy . As compared to Fe 3 O 4 /Ag microspheres, Fe 3 O 4 /GO/Ag composite microspheres displayed higher activity for SERS detection, and also catalytic reaction due to the synergistic interaction of GO nanosheets and Ag nanoparticles. Subsequently, the Fe 3 O 4 /GO/Ag composite microspheres were employed to quantitatively detect aromatic molecules, methylene blue (MB) in aqueous solution, showing the limit of detection was low down to 10 −9 M and the correlation coefficients (R 2 ) of the linear relationship between SERS intensities and logarithmic concentrations was high up to 0.91. Moreover, the Fe 3 O 4 /GO/Ag composite microspheres as catalysts completely degraded methylene blue and ciprofloxacin in 12 min with the presence of NaBH 4 . Finally, Fe 3 O 4 /GO/Ag composite microspheres were utilized to effectively follow the degradation reaction process of MB by SERS. Taken together, Fe 3 O 4 /GO/Ag composite microspheres present SERS application potentials in terms of trace and quantitative detection of chemicals, and in-situ monitoring catalytic degradation of organic pollutants.

ICG@ZIF-8/PDA/Ag composites as chemo-photothermal antibacterial agents for efficient sterilization and enhanced wound disinfection

Shuhan Hui,Qiqi Liu,Yandong Han,Lijuan Zhang,Jun Yang,Shan Jiang,Haisheng Qian,Wensheng Yang

Bacterial infection has increasingly affected people's lives, therefore it is significant to explore novel antibacterial agents and strategies for efficient disinfection. Herein, we designed ZIF-8 based composites ICG@ZIF-8/PDA/Ag, which encapsulate photothermal agent indocyanine green (ICG) and grow polydopamine (PDA) on their surface for in situ reduction to generate Ag nanoparticles. With 20 min of 808 nm laser irradiation at 1.5 W cm−2, 100 μg mL−1 ICG@ZIF-8/PDA/Ag exhibited 100% bactericidal effects toward E. coli and S. aureus bacteria resulting from both hyperthermia of ICG and PDA and chemical toxicity of the released Ag and Zn ions. When the bacterial incubation period was extended to 12 h, the minimum bactericidal concentration (MBC) of ICG@ZIF-8/PDA/Ag was reduced to 6.25 μg mL−1, and this extremely low MBC was due to the long-term chemo-photothermal combinational effect induced by NIR irradiation. Additionally, the composites successfully promote the healing of S. aureus infected wounds on mice. This work constructed photo-responsive antibacterial composites that realize chemo-photothermal synergistic therapy.

High-efficiency sandwich-like hierarchical AgBr-Ag@MIL-68(Fe) photocatalysts: Step-scheme photocatalytic mechanism for enhanced photoactivity

Ruowen Liang,Zhoujun He,Yi Lu,Guiyang Yan,Ling Wu

Although both step-scheme (S-scheme) heterojunction and metal–organic framework (MOF) photocatalysts have been intensively studied, few efforts have been devoted to combining them to establish high-performance MOF-based S-scheme photocatalysts. In this work, binary Ag@MIL-68(Fe) (Ag@MFe) hybrids were first fabricated by decorating Ag nanoparticles (Ag NPs) onto MIL-68(Fe), an Fe-based MOF. Owing to the high specific surface area of MIL-68(Fe), the plasmonic Ag NPs were uniformly distributed on its surface. Then, AgBr particles were deposited on the Ag@MFe hybrids via precipitation to form the final ternary sandwich-like hierarchical AgBr-Ag@MFe photocatalyst. The 30 %AgBr-1.5 %Ag@MFe sample exhibited excellent photocatalytic performance for the degradation of rhodamine B under visible light irradiation ( λ  ≥ 420 nm), with an effectiveness 9.2 and 2.1 times higher than those of the original MIL-68(Fe) and binary 1.5 %Ag@MFe hybrid, respectively. Furthermore, 30 %AgBr-1.5 %Ag@MFe performed as a high-efficiency bifunctional photocatalyst towards the detoxification of water contaminants (mixture of a dye and Cr(VI)). The significantly enhanced photoactivity was attributed to the effective spatial separation of photogenerated electron–hole pairs via S-scheme charge transfer. Moreover, the plasmonic Ag NPs assembled into the contact interface of AgBr and MIL-68(Fe) enhanced the vectorial interfacial electron transfer. The formation of an S-scheme heterojunction was supported by X-ray photoelectron spectroscopy and electron spin resonance studies. This novel bifunctional AgBr-Ag@MIL-68(Fe) hybrid photocatalyst system not only provides new opportunities for environmental remediation but also highlights a promising strategy to construct high-efficiency S-scheme photocatalysts.

Fiber-Optic Surface Plasmon Resonance Sensor for Trace Cadmium-Ion Detection Based on Ag-PVA/TiO2 Sensing Membrane

Ting Li,Wenlin Feng

Synergistic and On-Demand Release of Ag-AMPs Loaded on Porous Silicon Nanocarriers for Antibacteria and Wound Healing

Yao Jin,Yudong Yang,Wei Duan,Xuetong Qu,Jianmin Wu

Due to the abuse of antibiotics, antimicrobial resistance is rapidly emerging and becoming a major global risk for public health. Thus, there is an urgent need for reducing the use of antibiotics, finding novel treatment approaches, and developing controllable release systems. In this work, a dual synergistic antibacterial platform with on-demand release ability based on silver nanoparticles (AgNPs) and antimicrobial peptide (AMP) coloaded porous silicon (PSi) was developed. The combination of AgNPs and AMPs (Tet-213, KRWWKWWRRC) exhibited an excellent synergistic antibacterial effect. As a carrier, porous silicon can efficiently load AgNPs and AMP under mild conditions and give the platform an on-demand release ability and a synergistic release effect. The AgNPs and AMP coloaded porous silicon microparticles (AgNPs-AMP@PSiMPs) exhibited an acid pH and reactive oxygen species (ROS)-stimulated release of silver ions (Ag+) and AMPs under bacterial infection conditions because of oxidation and desorption effects. Moreover, the release of the bactericide could be promoted by each other due to the interplay between AgNPs and Tet-213. In vitro antibacterial tests demonstrated that AgNPs-AMP@PSiMPs inherited the intrinsic properties and synergistic antibacterial efficiency of both bactericides. In addition, wound dressing loaded with AgNPs-AMP@PSiMPs showed outstanding in vivo bacteria-killing activity, accelerating wound-healing, and low biotoxicity in aStaphylococcus aureus-infected rat wound model. The present work demonstrated that PSiMPS might be an efficient platform for loading the antibiotic-free bactericide, which could synergistically and on-demand release to fight wound infection and promote wound healing.

A rapid fluorescent ratiometric Ag+ sensor based on synthesis of a dual-emission ternary nucleotide/terbium complex probe

Suyue Liu,Jingjing Tian,Longjiao Zhu,Hongtao Tian,Min Yang,Kunlun Huang,Wentao Xu

To develop a fast, isothermal, enzyme-free and visible method for the on-site detection of silver ions (Ag + ), a ratiometric Ag + sensor was constructed based on a dual-emission ternary nucleotide terbium probe, fabricated by synthesizing the luminescent nanomaterial Luminol-GMP-Tb (LGT). We repositioned the fluorescent properties of the nanomaterial from the perspective of the inherent optical properties of two signal reporters (luminol and Tb 3+ ) through highlighting the absorption, fluorescence steady-state measurement and time-resolved properties. Furthermore, based on the ingenious coordination interaction and energy transfer among Ag + , luminol and GMP-Tb, we hypothesized and confirmed that Ag + induced morphology and luminescence changes of LGT through scanning electron microscopy and lifetime changes as well as fluorescence changes. Meanwhile, by means of a portable ultraviolet detector with dual wavelengths, based on the fluorescence excitation characteristics of each component, different photoluminescence color phenomena presented at different excitation wavelengths. Therefore, visual qualitative detection could be realized under a portable UV lamp with 254 nm for mainly visible green color change while 365 nm as built-in reference for blue-emitting luminol. The ratio calculation method and the enhanced luminescence ratio mechanism made LGT exhibited extremely high selectivity to Ag + . Quantitative detection Ag + was realized in two ranges of 0.1 μM ~ 6 μM and 6 μM ~ 100 μM with a minimum detection limit of 65 nM. The method has been successfully exploited in real water samples with recovery rate between 99.7% and 106.38%, showing broad application prospects in food safety and environmental monitoring for the on-site detection of Ag + .

A highly sensitive and selective colorimetric/fluorescent probe for the detection of Ag+ based on a croconium dye

Hong Wang,Yuehan Wu,Yuzhe Zhang,Man Zhou,Song Xu,Zhongyu Li

A novel colorimetric and fluorescent probe, 2,5-bis[3-ethyl-2-methylbenzothiazole]-croconine ( BBC ) has been synthesized and characterized. The BBC dye can effectively recognize Ag + in the presence of potentially competitive metal ions (Co 2+ , Na + , Cd 2+ , K + , Mg 2+ , Zn 2+ , Ca 2+ , Ba 2+ , Ni 2+ , Cr 3+ , Al 3+ ), which exhibited visible color change and fluorescence spectra behaviors. The Benesi-Hildebrand plot accurately showed the binding constant of BBC- Ag + . Correspondingly, the 1:1 stoichiometric structure of BBC and Ag + was evaluated by using Job’s plot. Moreover, the complex mechanism of BBC toward Ag + were also investigated by Fourier transform infrared (FT-IR) and 1 H nuclear magnetic resonance ( 1 H NMR). The results indicated that BBC could be used as a high effective colorimetric and fluorescent sensor to identify Ag + .

Facile preparation of Fe3O4/Ag/RGO reusable ternary nanocomposite and its versatile application as catalyst and antibacterial agent

Teng Chen,Yunlong Geng,Hongri Wan,Yan Xu,Yingmei Zhou,Xiangjun Kong,Jiaomei Wang,Yunhui Qi,Bing Yao,Zhaojian Gao

In this paper, Fe 3 O 4 /Ag/RGO reusable ternary nanocomposites are explored via a facile one-pot solvothermal strategies, and the catalytic performance and antibacterial activity are investigated in detail. The catalytic performance of Fe 3 O 4 /Ag/RGO towards the reduction of 4-NP into 4-AP is evaluated, and the reaction rate constant ( k ) for Fe 3 O 4 /Ag/RGO is calculated to be 0.03086 s −1 , which is higher than that of Fe 3 O 4 /Ag (0.01756 s −1 ), indicating the catalytic activity is improved after decorating Fe 3 O 4 /Ag onto the graphene sheet. The antibacterial experiment shows Fe 3 O 4 /Ag/RGO ternary nanocomposites present a wide range of antibacterial activities against Gram-positive bacteria ( S. aureus and B. cereus ) and Gram-negative bacteria ( E. coli and P. aeruginosa ). The minimal inhibitory concentrations (MIC) for Fe 3 O 4 /Ag/RGO nanocomposites against four bacterial species are determined. Additionally, Fe 3 O 4 /Ag/RGO nanocomposites also present high reusability as catalyst and antibacterial agent. The results illustrated in this paper imply that the multifunctional performances such as efficient reduction of 4-NP followed by superior anti-reproduction of pathogenic bacteria make the Fe 3 O 4 /Ag/RGO ternary nanocomposites a promising catalyst for dye-polluted water and disinfectant agent for wastewater treatment and purification.

GO/Au@Ag nanobones decorated membrane for simultaneous enrichment and on-site SERS detection of colorants in beverages

Lili Kong,Jie Chen,Meizhen Huang

In this paper, we have developed a graphene oxide/Au@Ag nanobones membrane (GO/Au@Ag NBs membrane) for simultaneous enrichment and SERS detection of colorants in beverages. Raman enhancement effect of Au@Ag nanobones (NBs) and enrichment capability of graphene oxide (GO) are contributed to the high sensitivity of GO/Au@Ag NBs membrane. Microporous membrane provides a support template for uniformly loading high-density GO/Au@Ag NBs. When beverage flow through the portable filtration unit with GO/Au@Ag NBs membrane, colorant molecules could be efficiently enriched. The prepared GO/Au@Ag NBs membrane exhibits an excellent sensitivity with a LOD of Rhodamine 6 G at 1.12 × 10 −9 mol/L, and has good performances of uniformity (with an RSD of 7.87 %), repeatability (with an RSD of 10.44 %), time stability (stored up to 60 days). Six types of colorants were sensitively detected combined with GO/Au@Ag NBs membranes, portable filtration unit and self-development portable Raman system. The lowest distinguished amounts of molecular accumulation are well below the maximum usage limits and the limits of visual recognition. Support vector machine model was established to identify the types of colorants, including colorants with coincident Raman peaks or similar visual colors, with an average accuracy of 94.8 %. In addition, GO/Au@Ag NBs membranes were used to enrich and detect colorant additives in commercial beverages, brilliant blue in energy beverage and carmine in bayberry wine were successfully detected. These results indicate GO/Au@Ag NBs membranes combined with a portable filtration unit can effectively enrich and rapidly detect colorants in beverages, and has great potential in the field of on-site and sensitive food safety detection.