INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2017
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IF 3.582
Yingjie Chen,Shiben Liu,Liyan Yu,Qiuhong Liu,Yongtao Wang,Lifeng Dong
Nanoparticles with core–shell or hollow interiors have immense potential for catalysis. Herein, Ag@M x Fe 3− x O 4 (M = Co, Mn) core–shell nanoparticles were firstly synthesized through a seed-mediated method. These particles were then loaded onto carbon catalyst supports to form Ag@M x Fe 3− x O 4 /C. Then, hollow-M x Fe 3− x O 4 /C was prepared with the diffusion of Ag from Ag@M x Fe 3− x O 4 /C in saturated NaCl solution at room temperature . As a result, Ag@MnFe 2 O 4 /C demonstrates better oxygen reduction reaction (ORR) activity than Ag@CoFe 2 O 4 /C and other Ag@Mn x Fe 3− x O 4 /C with various Mn/Fe ratios. Moreover, Ag@MFe 2 O 4 /C shows superior ORR catalytic activities over hollow-MFe 2 O 4 /C, which can be due to electronic coupling between Ag core and MFe 2 O 4 shell. Furthermore, Ag@MnFe 2 O 4 /C catalysts demonstrate high durability for the ORR in alkaline media and insensitivity to methanol. These findings will provide helpful guidance for design and fabrication of carbon-supported core–shell catalysts for ORR in the future.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Xiaofeng Dai,Wen Xu,Teng Zhang,Hongbin Shi,Tao Wang
The monodisperse Cu-Ag core-shell nanoparticles (Cu@Ag NPs) for electric conductive inks were successfully prepared by a simple two-step process consisting of thermal decomposition and galvanic displacement. It was found that 20 mol.% coverage of Ag enabled Cu@Ag NPs oxidation resisting with air. A new approach to achieve coalescence and sintering of Cu@Ag NPs at room temperature was proposed. 1-amino-2-propanol (MIPA), hydrophilic amine with a short C-chain, was first applied to replace the strong stabilizer, the strong stabilizer oleylamine (OAM) adsorbed on particles, thereby obtained preliminary agglomeration and hydrophobic -to- hydrophilic transition to improve the wetting capability of electrolyte solution on the surface of metal film. Then, the reducing electrolyte NaBH 4 solution was used as the destabilizing agent to deeply coalesce particles, and also inhibit the electrochemical corrosion. It takes only a few minutes to achieve sintering in air at room temperature. Due to the effective sintering at room temperature, the conductive patterns could be formed on thermo-sensitive substrates. The eventual resistivity was found to be as low as 36.3 μΩ·cm.
研究领域:
材料科学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2024
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IF 3.8
Li Jing,Lu Chaofen,Yang Shufen,Xie Qing,Danzeng Qunzeng,Liu Cui,Zhou Chuan-Hua
Dopamine (DA) is a potent neuromodulator in the brain that affects a wide range of motivated behaviors. Abnormal concentration of DA is related to a variety of diseases. Hence, it is imperative to establish a rapid and precise method for quantifying DA. In this work, we integrate orange-yellow emissive carbon dots (CDs) with target-induced silver deposition on gold nanoparticles (Au NPs), forming gold/silver core-shell nanoparticles (Au@Ag NPs), to construct a fluorometric and colorimetric dual-signal sensor for sensitive detection of DA. Au NPs and silver ions (Ag + ) have minimal effect on the fluorescence of CDs. DA can reduce the silver ions to Ag(0) on the surface of the Au NPs to form a silver shell, resulting in the blue-shift of the absorbance peak from 520 to 416 nm, which overlaps with the excitation spectrum of CDs. As a result, the system color turns from pink to orange-yellow, and the fluorescence of CDs is quenched due to the strong inner filter effect. The linear range of the colorimetry is 0.5–18 μM with a limit of detection (LOD) of 0.41 μM, while the linear range for the fluorometry method is 0.5–14 μM with a LOD of 0.021 μM. This method demonstrates notable advantages including a low detection limit, rapid response time, and straightforward operation in practical samples, showing great potential in biomedical analysis. Graphical abstract
研究领域:
生物医学工程
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分析化学
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产品关联
DOI
PubMed
高影响因子
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.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2022
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IF 4.889
Xiangyu Dou,Haoyang Huang,Xue Wang,Qiang Lin,Jinbing Li,Yu Zhang,Yongsheng Han
Nucleation is widely present in nature, from food production to haze generation. Owe to the spatiotemporal limitation in catching the dynamic characters of nucleation process, the theoretical development and the control technique of nucleation is far behind the demand. Here we report a strategy of controlling nucleation process via manipulating the collision of nucleation units, with the aim of disclosing the mechanism dominating the nucleation process. Silver nucleation is simulated at different collision conditions which is regulated by chemicals diffusion and reaction rate. It is found that the nucleation rate has a good linear relationship with the collision frequency, suggesting a collision dependent nucleation model. This model is evaluated by particles-based silver aggregation and validated by experiments conducted in an in-situ electron microscopy. Furthermore, the model is applied to the improved synthesis of silver catalysts for selective partial oxidation of ethylene.
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 7
·1063
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IF 5.719
Guannan Yang,Shaogen Luo,Tao Lai,Haiqi Lai,Bo Luo,Zebo Li,Yu Zhang,Chengqiang Cui
In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles (Cu@Ag NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, Cu@Ag NMPs with compact and uniform Ag shells, excellent sphericity and oxidation resistance were synthesized. The as-synthesized Cu@Ag NMPs show superior microvia filling properties to Cu nanoparticles (NPs), Ag NPs, and Cu NMPs. By developing a dense refill method, the porosity of the sintered particles within the microvias was significantly reduced from ~30% to ~10%, and the electrical conductivity is increased about twenty-fold. Combing the Cu@Ag NMPs and the dense refill method, the microvias could obtain resistivities as low as 7.0 and 6.3 μΩ·cm under the sintering temperatures of 220 °C and 260 °C, respectively. The material and method in this study possess great potentials in advanced electronic applications.Keywords:Cu-Ag core-shell nano-microparticles;microvias;vertical interconnection;blind hole filling;sintering
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2025
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IF 3.9
Jie Chen,Chenyi Zheng,Qiang Wang,Zhipeng Xu,Kui Meng
Many innovations have been made in the morphology and preparation methods of copper–silver core–shell nanomaterials (Cu@AgNMs). The most commonly used method for preparing Cu@AgNMs is to perform a replacement reaction by adding a complexing agent, but there is no universally accepted method to select a complexing agent. This study found that the best complexing agent for preparing Cu@AgNMs is a short-chain complexing agent containing hydrophilic groups through the role of different complexing agents in the synthesis of the material, and the higher the stability of the short-chain hydrophilic complexing agent, the better the integrity of the resulting silver layer. This study clarifies the mechanism of different complexing agents in the synthesis of Cu@AgNSs, provides a reliable reference for the convenient preparation of Cu@AgNMs, and helps us to understand the influence of complexing agents on the silvering effect of the replacement process, thereby promoting the widespread application of a complex-replacement technology.
研究领域:
材料科学
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纳米技术
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
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2014
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IF 5.9
Zhuangqiang Gao,Kaichao Deng,Xu-Dong Wang,Manuel Miró,Dianping Tang
Nanostructure-based visual assay has been developed for determination of enzymatic activity, but most involve in poor visible color resolution and are not suitable for routine utilization. Herein, we designed a high-resolution colorimetric protocol based on gold/silver core/shell nanorod for visual readout of alkaline phosphatase (ALP) activity by using bare-eyes. The method relied on enzymatic reaction-assisted silver deposition on gold nanorod to generate significant color change, which was strongly dependent on ALP activity. Upon target ALP introduction into the substrate, the ascorbic acid 2-phosphate was hydrolyzed to form ascorbic acid, and then, the generated ascorbic acid reduced silver ion to metal silver and coated on the gold nanorod, thereby resulting in the blue shift of longitudinal localized surface plasmon resonance peak of gold nanorod accompanying a perceptible color change from red to orange to yellow to green to cyan to blue and to violet. Under optimal conditions, the designed method exhibited the wide linear range 5–100 mU mL–1 ALP with a detection limit of 3.3 mU mL–1. Moreover, it could be used for the semiquantitative detection of ALP from 20 to 500 mU mL–1 by using the bare-eyes. The coefficients of variation for intra- and interassay were below 3.5% and 6.2%, respectively. Finally, this method was validated for the analysis of real-life serum samples, giving results matched well with those from the 4-nitrophenyl phosphate disodium salt hexahydrate (pNPP)-based standard method. In addition, the system could even be utilized in the enzyme-linked immunosorbent assay (ELISA) to detect IgG at picomol concentration. With the merits of simplification, low cost, user-friendliness, and sensitive readout, the gold nanorod-based colorimetric assay has the potential to be utilized by the public and opens a new horizon for bioassays.
研究领域:
生物化学
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医学检验
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Kaifeng Wang,Jiayue Wen,Jiayun Feng,Yiping Wang,Peng Wu,Shang Wang,Yanhong Tian
The emergence of Cu@Ag core-shell nanoparticles presents a promising solution to address issues such as copper oxidation, the high cost of silver, and electro-chemical migration in high-power electronic devices, showcasing their potential for practical applications. In this study, Cu@Ag nanoparticles were synthesized via a liquid-phase reduction method, resulting in an average size of 30 nm. A low-boiling-point mixed organic solvent was meticulously prepared following Raoult's law, enabling the creation of a nano paste utilizing Cu@Ag nanoparticles. This innovation facilitated the sintering of fully dense joints under ambient air conditions, effectively mitigating the oxidation issue caused by silver dewetting behavior in Cu@Ag core-shell nanoparticles. Subsequently, the shear strength and microstructure of the joints were comprehensively studied under various sintering temperatures and durations. Notably, the joint exhibited a shear strength of 17.3 MPa when sintered at 250 °C for 30 min, while achieving full density at a sintering temperature of 300 °C for 30 min. These findings underscore the capacity of Cu@Ag core-shell nano paste to enable the production of high-performance joints under air conditions, utilizing thoughtfully selected organic components.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
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2016
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IF 7.476
Long Wu,Xiaoyan Xiao,Kun Chen,Wenmin Yin,Qin Li,Pan Wang,Zhicheng Lu,Jing Ma,Heyou Han
Abstrcact Highly sensitive and selective detection of specific DNA sequences is of great importance in clinical diagnosis, environmental and food monitoring, but it still remains challenges to develop a facile method for real sample detection in aqueous solution. Here, a simple and recyclable surface enhanced Raman scattering (SERS) sensor was constructed for Bacillus thuringiensis (Bt) special gene fragment detection by Fe 3 O 4 magnetic beads (MBs) and Au–Ag core-shell nanorods (Au@Ag NRs). A hairpin DNA with sulfhydryl and biotin was attached to Au@Ag NRs as indicator, and MBs with streptavidin (SA) were acted as the capture probe. On the basis of the biotin–SA specific interaction, target sequences were first hybridized with the hairpin DNA and exposed the biotin. Subsequently, the Au@Ag NRs were captured by the streptavidin modified MBs, which reduced the suspended NRs and led to the change of Raman intensity . Under the optimal conditions, the SERS intensity revealed a good linearity with Bt transgene fragment ranging from 0.1 pM to 1 nM with a detection limit of 0.14 pM (S/N=3). To demonstrate the specificity of the strategy, the single-base mismatch in DNA was discussed in the SERS assay. The results showed that the sensitivity and accuracy of the proposed method was acceptable in DNA detection, revealing a great potential in special gene detection.
研究领域:
生物技术
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分析化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 41
·35001-35007
·
IF 3.289
Xuehong Zhang,Min Wei,Bingjing Lv,Yuanjian Liu,Xu Liu,Wei Wei
Glucose and cholesterol in human fluids are clinically important analytes and their sensitive detection is significant in diagnosis. In this study, Au@Ag core–shell nanoparticles (Au@Ag NPs) prepared by in situ growth of silver nanoparticles (AgNPs) on the surface of thiol-PEG-capped gold nanoparticles (AuNPs, 13 nm) have been successfully applied to fabricate a colorimetric biosensing platform for glucose and cholesterol. Au@Ag NPs showed an obvious absorbance peak at 375 nm due to the surface plasmon resonance (SPR) absorption of AgNPs. In the presence of cholesterol and glucose, H2O2 was produced under the catalytic action of their corresponding enzymes such as glucose oxidase (GOx) or cholesterol oxidase (ChOx), which etched the AgNPs shell of Au@Ag NPs. As a result, their characteristic absorbance at 375 nm decreased, accompanied with a perceptible color change from orange to red, which could be used to detect glucose and cholesterol by the naked eye. Under optimum conditions, the linear ranges for the detection of glucose and cholesterol by UV-vis spectroscopy were from 0.5 to 400 μM and 0.3 to 300 μM, respectively. The detection limit of the biosensors for glucose and cholesterol were 0.24 μM and 0.15 μM, respectively. The practical applications of this method in urine or human serum have been realized with satisfactory results. This work provides a simple and sensitive approach for glucose and cholesterol detection, which has broad application prospects in clinical diagnosis.
研究领域:
生物医学
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纳米技术
·
临床诊断
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Tianhui Jiao,Waqas Ahmad,Jiaji Zhu,Md Mehedi Hassan,Jingjing Wang,Yawen Rong,Zhiming Guo,Huanhuan Li,Zhen Ding,Changxin Lv,Quansheng Chen
The current study examines aflatoxin B1 (AFB1) as the indicator of the total aflatoxins in wheat with a 5-aminotetramethylrhodamine (NH 2 -Rh)-decorated gold–silver core–shell nanoparticles (Au@Ag CSNPs) sensor based surface enhanced Raman scattering (SERS) strategy, using Hg(II) as the media. The principle of the work was based on the selective interaction of Hg(Ⅱ) media with AFB1 via carbonyl oxygen atoms to inhibit the aggregation of NH 2 -Rh-Au@Ag CSNPs sensor. Due to the nanogap effect induced by sensors aggregation, the quenching in SERS intensity was an indication for AFB1 selective quantification. Under the optimized experimental conditions, a detection limit of 0.03 ng·mL −1 was obtained with a correlation coefficient R 2 = 0.9895 within the dynamic range of 0.1–5.0 ng·mL −1 . This quantification of AFB1 was further coupled with solid-phase extraction in real wheat, hazelnut, and peanut oil samples. The strategy was validated by standard HPLC-FLD approach and was in a good agreement. The proposed detective system offers a promising platform for the rapid determination of traces AFB1 residue in foodstuff with high selectivity and economical efficiency.
研究领域:
食品安全
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分析化学
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）