ACS Applied Nano Materials
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2023
·
IF 5.9
Wenwen Fu,Wentong Yang,Chen Qian,Yaqin Fu,Yaofeng Zhu
Heterointerfaces in microwave absorption materials can induce dielectric polarization relaxation for superior microwave absorption capacity. Nevertheless, the construction of favorable hierarchical structures in dielectric heterogeneous materials remains a considerable challenge. Herein, Ag/AgCl heterojunction (HAg) nanoparticles are successfully decorated on polyaniline (PANI)/graphene oxide (GO) sheets through simple one-pot interfacial polymerization. The synthesized HAg/PANI/GO hybrid exhibits superior microwave absorption performance due to the multi-heterogeneous and hierarchical structures, which provides numerous interface polarizations, dipolar relaxations, and improved impedance matching. The minimum reflection loss of the optimum HAg/PANI/GO hybrid reaches −61.14 dB at 11.32 GHz with an effective absorption bandwidth of 4.77 GHz in the range from 9.70 to 14.47 GHz. This work provides ideas for producing multi-heterogeneous and hierarchical structures to reach a high microwave absorption performance.
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ANALYTICA CHIMICA ACTA
·
2023
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IF 6.2
Huasheng Lai,Gongke Li,Zhuomin Zhang
A bioinspired Au@Ag nanodome-cones array (Au@Ag NDCA) surface-enhanced Raman scattering (SERS) chip was developed for efficient residue analyses of food samples. The cicada wing inspired Au@Ag NDCA chip was fabricated by a bottom-up method, Au nanocones array was firstly grown onto nickel foil by displacement reaction and cetyltrimethylammonium bromide guidance growth, and then silver shell with controllable thickness was coated onto the Au nanocones array by magnetron sputtering . The Au@Ag NDCA chip exhibited good SERS performances with high enhancement factor of 1.2 × 10 8 , good uniformity with relative standard deviation (RSD) less than 7.5% (n = 25), good inter-batch reproducibility with RSD less than 9.4% (n = 9), and long-term stability over 9 weeks. By adapting a minimized sample preparation, Au@Ag NDCA chip combined with a 96-well plate could realize high-throughput SERS analyses of 96 samples with average analysis time less than 10 min. The substrate was applied for quantitative analyses of two food projects. One was 6-benzylaminopurine auxin residue in sprout samples with detection limit of 38.8 μg/L, recoveries of 93.3–105.4% and RSDs of 1.5–6.5%, and the other was an edible spice of 4-amino-5,6-dimethylthieno (2,3-d) pyrimidin-2(1H)-one hydrochloride additive in beverage samples with detection limit of 18.0 μg/L, recoveries of 96.2–106.6% and RSDs of 3.5–7.9%. All the SERS results were well confirmed by conventional high-performance liquid chromatographic methods with relative errors less than 9.7%. The robust Au@Ag NDCA chip exhibited good analytical performances possessed great potential for convenient and reliable analyses of food quality and safety.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
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IF 7.2
Minghua He,Zulhumar Turup,Xuekun Jin,Fengjuan Chen
MnO 2 is considered to be one of the most promising electrocatalysts for oxygen reduction reactions (ORR) in alkaline media and can be applied to various electrochemical energy conversion and storage devices. However, it is limited by the relatively slow kinetics of the cathodic electrochemical reactions . In addition, it is difficult to control the presence state of Ag during the modification of MnO 2 . To this end, an efficient ORR electrocatalyst of Ag nanoparticles supported by MnO 2 nanorods was successfully synthesized by using NH 3 ·H 2 O as a complexing agent to inhibit the Ag + intercalating into the tunnels of MnO 2 . The half-wave potential ( E 1/2 ) and limiting current density ( J lim ) of the obtained Ag/MnO 2 electrocatalysts are 0.81 V and −5.6 mA cm −2 , respectively, showing comparable ORR catalytic activity to commercial Pt/C catalysts. The excellent catalytic performances can be attributed to the presence of abundant oxygen vacancies and Mn 3+ species on the MnO 2 surface, as well as the synergistic effect between MnO 2 substrates and Ag nanoparticles. Among them, oxygen vacancies enhances the adsorption of O 2 , Mn 3+ facilitates the displacement of O 2 2− /OH − , MnO 2 inhibits the accumulation of peroxide species to improving the oxygen environment on the Ag surface and Ag accelerates the electron transfer in the whole process. This work provides a useful guide for the design of efficient Mn-based ORR electrocatalysts.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Xiaoqi Liu,Yanyun Zhang,Yan Liu,Ting'an Zhang
Chitosan bead grafted by third-generation dendrimers (CB-G3) with a diameter of 1.40 mm was synthesized to investigate their performance in recovering Ag(I), Cu(II), and Pb(II) ions in aqueous media. The prepared adsorbents were characterized by XRD, FT-IR, elemental analysis, TGA , and SEM, and the effects of pH, contact time, concentration, and temperature were examined. The results showed that the adsorbents were successfully fabricated. The optimum pH value was 5, and the increased generation number contributed to adsorption capacity improvement, indicating that electrostatic interactions between amine groups and metal ions are the governing mechanism of adsorption by the CB-G3. The kinetics, isotherms, and thermodynamics of Ag(I), Cu(II), and Pb(II) adsorption onto the CB-G3 were investigated. The adsorption processes can be described using pseudo-second-order kinetic and Langmuir models. The maximum monolayer adsorption capacities were 105.62, 88.82, and 97.87 mg·g −1 for Ag(I), Cu(II), and Pb(II) at 30 °C within 210 min, respectively. Electrostatic interactions and hydrogen bonds are the main mechanisms between metal ions and N atoms. Therefore, the CB-G3 is a promising candidate for Ag(I), Cu(II), and Pb(II) adsorption owing to its splendid ability in easy separation, good adsorptivity, and reusability for efficiently adsorbing Ag(I), Cu(II), and Pb(II) ions.
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TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
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2023
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IF 4.5
Hao LEI,Yan LI,Meng-wei GUO,Qi-bo ZHANG
Smooth Ag substrate achieved in-situ conversion to form nanoporous architecture that is assembled by highly dispersed nanoparticles (NPs) with a mean size of 21.88 nm by applying a redox potential signal in an alkaline solution with an appropriate pH range. The detailed phase constitution and microstructure evolution process of the Ag substrate induced by the electrochemical redox tuning approach were systemically investigated. Under the action of controllable redox potentials, the smooth Ag substrate is firstly electrochemically oxidized to form Ag 2 O with an expansion on the unit volume, followed by electrochemical reduction back to metallic Ag, causing the cell volume to shrink. The expansion and contraction of the unit volume during the highly reversible electrochemical process lead to in-situ formation of the highly porous Ag architectures. The fabricated Ag NPs-packed electrode exhibits as an excellent surface-enhanced Raman scattering (SERS) performance, and the measured Raman spectrum of Rhodamine 6G (R6G) reaches a detection limit of 5.44×10 −10 mol/L.
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TALANTA
·
2023
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IF 6.1
Jianxia Cheng,Zhiyang Zhang,Longfei Zhang,Jiaqi Miao,Yan Chen,Rongfang Zhao,Meichun Liu,Lingxin Chen,Xiaoyan Wang
Making metal nanoparticle aggregates is a common way to improve surface-enhanced Raman scattering (SERS) enhancement via the formation of hot spots between nanoparticles . Here, we propose a “freeze-thaw-ultrasonication” method to obtain stable colloidal Ag nano-aggregates (AgNAs) with controllable sizes, which can remain stable for a few days. Compared with other method using aggregation reagents (e.g., organic molecules and salt), this method can maintain metal surface charges and adsorption affinity, which ensures the excellent SERS stability and sensitivity. The SERS detection window during the experiment can reach more than 25 min, which makes it a prerequisite for accurate SERS detection during a long-time range. Combining the obtained stable AgNAs with microfluidic devices, we established a sequential SERS on-line continuous detection method for the high-throughput detection of multiplex samples. The UV-Fenton degradation process of methylene blue (MB) is continuously on-line monitored through this platform, which is more sensitive than the UV–Vis Spectrum. Moreover, we have realized the sensitive and accurate detection of 5-nitro-8-hydroxyquinoline (5-NQ) with antibacterial and anticancer activities based on chloride-functionalized silver , which paved a way for SERS high-throughput analysis in bioanalysis and other fields.
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FOOD AND AGRICULTURAL IMMUNOLOGY
·
2022
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IF 3.268
Peizhen Li,Xiuhua Xia,Jiannan Chen,Hang Yu,Yunfei Xie,Yahui Guo,Weirong Yao,He Qian,Yuliang Cheng
Gold-coated silver core–shell nanoparticles (Ag@Au NPs) have been widely used for SERS analysis due to plasmon resonance performances. However, it is a great challenge to fabricate Ag@Au core–shell structures with specified morphology. In this paper, the size and shape of Ag NPs (core) were precisely controlled by a seed-mediated approach, and then the gold shell was completely coated on under the strong reduction of ascorbic acid, resulting in Ag@Au NPs with highly regulated morphology. The obtained Ag@Au NPs achieved a similar or even better SERS enhancement factor (EF) (up to 5.7 × 107) compared to Ag NPs, but significantly higher stability. For the rapid SERS detection of nitrofurantoin metabolite AHD, a limit of detection (LOD) as low as 1 × 10−10 M and a wide linear range from 1 × 10−4 to 1 × 10−8 M were obtained. Furthermore, recoveries for crayfish samples were from 90.5% to 108%, indicating a good performance of the presented method in real sample detection.
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RSC Advances
·
2019
·Vol. 9
·期 6
·2877-2884
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IF 3.049
Yanlin Li,Sen Yang,Xuegang Lu,Wenyuan Duan,Toshihiro Moriga
Fe3O4–Ag Janus composites were synthesized using a two-step solvothermal method. The optimal growth process was determined by investigating the relationship between the particle morphologies and reaction time. Magnetic and Raman spectroscopic measurements showed that the as-synthesized Janus composites have both good magnetic response and significant surface-enhanced Raman scattering (SERS) effects, as well as reproducibility. The calculated Raman enhancement factor reached an unprecedented magnitude of 109 compared with the values of other Fe3O4–Ag compounds. Furthermore, the SERS effect was exhibited even at a concentration of probe molecules as low as 10−13 M. This demonstrates that the as-synthesized Fe3O4–Ag Janus composite particles have promise for application as separable, highly sensitive SERS substrates.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2019
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IF 2.931
Shu Huan Ren,Shi Gang Liu,Yu Ling,Nian Bing Li,Hong Qun Luo
In this work, novel photoluminescent Ag nanoclusters (Ag NCs) with red emission are synthesized and successfully used for detecting iodide ion (I − ). The dihydrolipoic acid (DHLA) is used as the stabilizing agent and beta-cyclodextrin (β-CD) is used as the auxiliary stabilizing agent. DHLA and β-CD are combined with Ag atoms by the formation of Ag S bonds and hydrophobic interaction, respectively. Functionalization of β-CD endows good photoluminescent properties and solubility in water to the Ag NCs. The obtained DHLA and β-CD-protected Ag NCs (DHLA/β-CD-Ag NCs) are spherical and display a dispersed state. However, the DHLA/β-CD-Ag NCs are aggregated in the presence of I − , accompanied by the decrease in their fluorescence intensity . Because the integrity of β-CD cavities is retained on the surface of DHLA/β-CD-Ag NCs, which preserves their capability for I − host–guest recognition, the DHLA/β-CD-Ag NCs combine with I − through the formation of inclusion complexes. Based on this phenomenon, the prepared DHLA/β-CD-Ag NCs can be designed as a novel fluorescent probe for I − detection. The limit of detection (LOD) is calculated as 0.06 μM, indicating that it is an ideal probe for I − detection in practical applications.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Yufeng Yao,Jia Fan,Ming Shen,Weizheng Li,Bin Du,Xue Li,Jingtao Dai
In this study, hexylresorcinol calix[4]arene (HRCA) is introduced into the reaction system, and HRCA-capped ZnO–Ag nanocomposites are prepared via a simple one-step reflux method. HRCA is used not only as a reducing agent for deoxidizing Ag + to Ag, but also as a protectant for wrapping around the microstructure of the formed ZnO–Ag. The prepared samples are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and water contact angle. The Ag nanoparticles and ZnO adhere to each other and HRCA molecules encapsulate on the surface of ZnO–Ag nanocomposites. HRCA-capped ZnO–Ag nanocomposites with different Ag contents are investigated for use in photodegradation of organic pollutants (rhodamine B (RhB) and levofloxacin hydrochloride). The sample with 10.20 mol% Ag, denoted as ZA3, exhibits the highest catalytic activity for photodegradation of RhB and levofloxacin hydrochloride. Moreover, ZA3 exhibits high stability during photodegradation of organic pollutants even after multiple reuses. The possible photocatalytic mechanism is discussed. We believe that O 2 − and h + are the chief active species responsible for the photocatalytic activity of HRCA-capped ZnO–Ag nanocomposite system. HRCA-capped ZnO–Ag nanocomposite is expected to be an effective photocatalyst with potential application to sewage treatment under sunlight.
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CARBON
·
2019
·
IF 7.466
Yong Han,Limei Shi,Xueli Luo,Xiumei Chen,Weixia Yang,Wenzhi Tang,Jianlong Wang,Tianli Yue,Zhonghong Li
Sulfhydryl functionalized carbon dots (HS-CDs) mediated by Ag + were used to develop a fluorescent sensor for the determination of Hg 2+ in aqueous solutions. FTIR and XPS confirmed the successful modification of -SH on the surface of HS-CDs. Dripping Ag + into HS-CDs yielded brown agglomerates of silver thiolate leading to strong FL quenching of the HS-CDs. The signal-on fluorescent sensor was acheived by dispersing the precipitates in a PBS buffer (pH 7.4, 0.01 mol/L). Remarkable FL recovery was observed upon the addition of Hg 2+ into the sensor owing to the energy trap induced by exposure of -NH 2 on the surface of the HS-CDs. Fluorescence intensities of the HS-CDs were linearly recovered in Hg 2+ concentrations of 0.01–0.75 nmol/L with an extremely low detection limit of 4.2 pmol/L. The sensor exhibited stronger specificity toward Hg 2+ than co-existent metal ions. The detecting results for real water samples obtained by the sensor showed good agreement with ICP-AES (P > 0.05), demonstrating a sensitive and selective fluorescent nanosensor for ultra-trace determination of Hg 2+ with acceptable precision and satisfactory accuracy.
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BIOELECTROCHEMISTRY
·
2019
·
IF 4.474
Pan Zhang,Tingting Sun,Shengzhong Rong,Dongdong Zeng,Hongwei Yu,Ze Zhang,Dong Chang,Hongzhi Pan
Long-term accumulation of organophosphate pesticides in environment presents a potential hazard to human and animal health. Towards this, a highly sensitive amperometric AChE-biosensor based on conjugated polymer and Ag-rGO-NH 2 nanocomposite has been successfully developed. First, 4, 7-di (furan-2-yl) benzo thiadiazole (FBThF) was electrochemically polymerized on the electrode surface. Then, Ag-rGO-NH 2 nanocomposite and acetylcholinesterase (AChE) are modified on the polymer membrane surface. In this way, a novel amperometric AChE-biosensor was successfully prepared. The as-prepared biosensor possessed excellent conductivity, catalytic activity , and biocompatibility which were attributed to the synergistic effects of poly(FBThF) and Ag-rGO-NH 2 and provided a hydrophilic surface for AChE adhesion. Under optimized conductions, the linear range was 0.099–9.9 μg L −1 with a regression coefficient of 0.9947 for malathion , 0.0206–2.06 μg L −1 with a regression coefficient of 0.9969 for trichlorfon . The detection limit is calculated to be about 0.032 μg L −1 for malathion and 0.001 μg L −1 for trichlorfon (S/N = 3). Moreover, the biosensor exhibited acceptable reproducibility and long-term stability, which makes it possible to provide a novel and promising tool for analysis of organophosphate pesticides.
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