RSC Advances
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2014
·Vol. 5
·期 8
·6043-6050
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IF 3.708
Jiang Xue Dong,Fei Qu,Nian Bing Li,Hong Qun Luo
This paper reports a dramatic cyclic regeneration of polyethyleneimine-templated silver nanoclusters (PEI-AgNCs) based on the pH-induced conformational changes of polyethyleneimine (PEI) in aqueous solution. The PEI-AgNCs have been synthesized and found to be highly sensitive to the pH of the solution in air. The studies show that small AgNCs would gather to form larger silver nanoparticles (AgNPs) by adjusting the pH to 1.5 with a nitric acid solution. The AgNPs in solution was then transformed gradually to Ag(I) ions with stirring in air. Subsequently, the above Ag(I) ions were reduced again to AgNCs by changing the pH to about 9 with a NaOH solution and adding a certain amount of formaldehyde as a reductant to solution. The fluorescence and UV-visible absorption spectra recorded this process in detail. The transmission electron microscopy images, X-ray powder diffraction patterns, and Fourier transform infrared spectra further demonstrated that the cyclic transformation existed among AgNCs, AgNPs, and Ag(I) ions. The amino-rich PEI plays a crucial role in the regeneration of PEI-AgNCs. A large number of amino groups on PEI could be reversibly protonated by adjusting the pH of solution, leading to a change of the interaction between Ag and PEI, which has laid foundation for this work.
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Scientific Reports
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2015
·Vol. 5
·期 1
·1-8
·
IF 5.578
Shen Mo-Hai,Zhou Xiao-Xia,Yang Xiao-Ya,Chao Jing-Bo,Liu Rui,Liu Jing-Fu
It is still not very clear what roles the various Ag species play in the toxicity of silver nanoparticles (AgNPs). In this study, we found that traditional exposure media result in uncontrollable but consistent physicochemical transformation of AgNPs, causing artifacts in determination of median lethal concentration (LC50) and hindering the identification of Ag species responsible for the acute toxicity of AgNPs to Daphnia magna . This obstacle was overcome by using 8 h exposure in 0.1 mmol L −1 NaNO 3 medium, in which we measured the 8-h LC50 of seven AgNPs with different sizes and coatings and determined the concentrations of various Ag species. The LC50 as free Ag + of the seven AgNPs (0.37–0.44 μg L −1 ) agreed very well with that of AgNO 3 (0.40 μg L −1 ) and showed the lowest value compared to that as total Ag, total Ag + and dissolved Ag, demonstrating free Ag + is exclusively responsible for the acute toxicity of AgNPs to D. magna , while other Ag species in AgNPs have no contribution to the acute toxicity. Our results demonstrated the great importance of developing appropriate exposure media for evaluating risk of nanomaterials.
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CRYSTENGCOMM
·
2013
·Vol. 16
·期 12
·2384-2394
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IF 3.879
Zhifeng Jiang,Jianjun Zhu,Dong Liu,Wei Wei,Jimin Xie,Min Chen
Considering that the reduction of particle size can increase the number of active sites, particle size is accepted to be the key factor in the design of photocatalysts. However, serious agglomeration of nanosized particles may cause not only a decreased surface area but also increase grain boundary recombination. Forming a hollow nano-hemisphere in single crystals with reactive sites could be a good method to overcome this drawback. In this work, we report the synthesis of novel anatase TiO2 hollow nano-hemispheres by using a mixture of CH3COO− and F− as size and morphology controlling co-agents that prevent aggregation and increase the number of active sites. Furthermore, bimetallic Ag/Pt nanoparticles (NPs) are uniformly loaded on both interior and exterior of the nano-hemispheres in situ. The Ag/Pt@TiO2 NPs with improved visible-light-harvesting ability, high charge–hole mobility, and low electron–hole recombination exhibited improved photocatalytic performance in the degradation of rhodamine B/ciprofloxacin (RhB/CIP) and hydrogen generation. The results presented here give a promising way toward the development of delicate bimetal@semiconductor composites for board applications in photocatalysis.
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SENSORS AND ACTUATORS B-CHEMICAL
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2014
·
IF 3.84
Weiyan Liu,Hongmei Yang,Shenguang Ge,Lei Shen,Jinghua Yu,Mei Yan,Jiadong Huang
In this paper, PtPd alloy decorated reduced graphene oxide (RGO/PtPd) was synthesized by a simple and green method. The RGO/PtPd could catalytic oxidation of H 2 O 2 to form O 2 and O 2 acted as the coreactant of peroxydisulfate, could greatly amplify the ECL signal. Moreover, the RGO/PtPd exhibited higher catalytic activity compared to the RGO/Pt or RGO/Pd catalyst because of the synergetic effects of Pt and Pd and the enhanced electron transfer of RGO. Based on this, a highly sensitive and selective label-free electrochemiluminescence (ECL) aptasensor for detection of adenosine triphosphate was designed. In this process, RGO/PtPd could be regarded as mimicking enzyme, the effect of which was similar to horseradish peroxidase in generating O 2 and also used as carriers to immobilize ssDNA2. With respect to sensitivity, Ag dendrites with hierarchical nanostructures were electrodeposited on working electrode of portable indium tin oxide device, which improved the electronic transfer rate as well as increased the amount of immobilized capture ssDNA1. Under the optimal conditions, the approach provided a linear range from 0.1 pM to 50 nM and a low detection limit of 0.037 pM.
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SENSORS AND ACTUATORS B-CHEMICAL
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2015
·
IF 4.097
Ziying Wang,Yong Zhang,Sen Liu,Tong Zhang
A novel NO 2 gas sensor has been constructed using Ag nanoparticles-SnO 2 nanoparticles-reduced graphene oxide (AgNPs-SnO 2 -rGO) hybrids as sensing materials. AgNPs-SnO 2 -rGO hybrids were prepared by a two-step wet-chemical method. Firstly, SnO 2 -rGO hybrids were synthesized by hydrothermal treatment of aqueous dispersion of GO in the presence of SnCl 4 . Then, AgNPs-SnO 2 -rGO hybrids were obtained by in situ reduction of AgNO 3 on the surface of SnO 2 -rGO hybrids. The combined characterizations of UV–vis spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectrometer (EDX), elemental mapping, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and Raman spectra were used to investigate the structure of AgNPs-SnO 2 -rGO hybrids. Most importantly, the sensor based on AgNPs-SnO 2 -rGO hybrids exhibits good sensing performance for NO 2 sensing operating at room temperature . For example, the response time and recovery time of the sensor based on AgNPs-SnO 2 -rGO hybrids for 5 ppm NO 2 are 49 s and 339 s, which are much shorter than that of SnO 2 -rGO hybrids (415 s and 740 s), indicating that the sensing performances for NO 2 sensing at room temperature have been tremendously enhanced by introduction of AgNPs into SnO 2 -rGO hybrids.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2014
·Vol. 406
·期 25
·6337-6346
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IF 3.578
Chen Peng,Wang Zhuyuan,Zong Shenfei,Chen Hui,Zhu Dan,Zhong Yuan,Cui Yiping
p -Aminothiophenol (pATP) functionalized multi-walled carbon nanotubes (MWCNTs) have been demonstrated as an efficient pH sensor for living cells. The proposed sensor employs gold/silver core-shell nanoparticles (Au@Ag NPs) functionalized MWCNTs hybrid structure as the surface-enhanced Raman scattering (SERS) substrate and pATP molecules as the SERS reporters, which possess a pH-dependent SERS performance. By using MWCNTs as the substrate to be in a state of aggregation, the pH sensing range could be extended to pH 3.0∼14.0, which is much wider than that using unaggregated Au@Ag NPs without MWCNTs. Furthermore, the pH-sensitive performance was well retained in living cells with a low cytotoxicity. The developed SERS-active MWCNTs-based nanocomposite is expected to be an efficient intracellular pH sensor for bio-applications.
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NANO
·
2017
·
IF 1.025
Xiuhua Li,Jian Lin,Junhong Zhao
A novel composite nanostructure which is made up of TiO 2 three dimensionally ordered macroporous (3DOM) nanostructure and TiO 2 nanorods (NRs) has been successfully synthesized through a combination of colloidal crystal template technology and hydrothermal method, then we achieved its combination with Ag nanoparticles (NPs) via a silver mirror reaction. We studied the SERS (Surface-Enhanced Raman Scattering) performance of the obtained structure, the results show that our samples are very sensitive substrates when being used to detect dye R6G molecules, with a low detection concentration of 10 − 1 1 M. This proves that it is a promising material in the area of analyzing and molecule-level detecting as a kind of novel and low-cost SERS substrate.
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Food Packaging and Shelf Life
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2024
·
IF 8.5
Jing Yi,Shuqi Zhang,Xuanxuan Yuan,Zhilong Zhang,Zhongguo Shan,Haihua Wang
The increasing emphasis on food quality and consumer safety has prompted researchers to explore green manufacturing techniques for packaging materials. In this study, γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs) were prepared as promising nanocarriers for gallic acid (GA) and silver nanoparticles (Ag NPs). These nanocarriers (GA-Ag@CD-MOFs) were further incorporated into a zein matrix to fabricate multifunctional composite films, referred to as MOFs-Zein. Scanning electron microscopy (SEM) and atomic force microscope (AFM) analysis indicated that the fabricated composite film exhibited excellent biocompatibility, with GA-Ag@CD-MOFs uniformly dispersed within the film matrix. Fourier transform infrared spectroscopy (FT-IR) result revealed that the incorporation of GA-Ag@CD-MOFs facilitated the formation of intermolecular hydrogen bonds with the matrix polymer. The addition of GA-Ag@CD-MOFs enhanced the tensile strength of the composite film by 19.70 %, improved the water barrier performance by 57.76 %, and provided almost 100 % UV protection. The exceptional controlled release capability of γ-CD-MOFs for GA empowered the composite films to maintain their robust initial antioxidant capacity even after 100 days of storage. Moreover, the composite films performed high-efficiency antibacterial activity against Escherichia coli O157:H7 and Salmonella enterica . Acute toxicological studies showed no histopathology related toxicity was found in GA-Ag@CD-MOFs treated mice. When applied to fresh pork, the composite films significantly reduced the key quality indicators of raw meat, compared to the control film. Overall, this work presents a promising approach to fabricate the composite films as a sustainable and functional solution for green functional food packaging.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
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2024
·
IF 4
Luqi He,Peihuan He,Jiacong Li,Meng Xiong,Yeshun Zhang,Hui Yan
The residue of pesticide fenthion is a common issue in food safety, and how to conveniently detect it is a challenge in the food industry. Therefore, combined with a portable Raman spectrometer, a surface enhanced Raman spectroscopy (SERS) method based on a high-performance substrate Au@AgNPs had been designed for the rapid and sensitive detection of fenthion. Au@AgNPs can be induced to generate more hot spots to improve SERS signals because of their core-shell structure. The quantitative detection of fenthion was achieved under the optimal conditions: pH 7.0, 10 −3 M CaCl 2 , 70 % Au@AgNPs concentration, and 4 min of incubation time. The results showed that the method had a wider detection range of 0.1–100 mg/L, a low detection limit (LOD) of 0.036 mg/L, excellent anti-interference ability, and reproducibility. In addition, the method was successfully validated with the actual sample rice. Therefore, the method had the advantages of being fast, on-site, and easy to use, which is useful for promoting its application.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
·
IF 8.1
Peilin Jia,Dongzhi Zhang,Xingyan Shao,Jieshuo Zhai,Jishun Guo,Zijian Wang,Xinyi Ji
Hydrogen (H 2 ), as a clean energy source, exhibits significant promise in the realm of new energy vehicles. Utilizing hydrogen sensors with rapid response and high selectivity is crucial for monitoring vehicles and preventing hydrogen leakage incidents. In this study, In 2 O 3 nanomaterials were synthesized via a hydrothermal approach and effectively modified with Ag/Cu bimetallic nanoparticles to fabricate high-performance hydrogen sensors. The optimal work temperature for the Ag/Cu–In 2 O 3 sensor is determined to be 300 °C. At this temperature, the sensor exhibited a response of 9.66–100 ppm H 2 , which is four times higher than the pristine In 2 O 3 sensor. Excellent H 2 selectivity and outstanding long-term stability were exhibited by the sensor in typical interference gas environments encountered in new energy vehicles. The significant enhancement in sensor performance is attributed to the electronic and chemical sensitization effects of Ag/Cu bimetals and the synergistic effects of bimetallic modification. Additionally, computational studies based on density functional theory (DFT) further elucidated the reasons for the improved H 2 gas sensing performance of Ag/Cu–In 2 O 3 nanocomposites. The Ag/Cu–In 2 O 3 nanocomposites show great potential for hydrogen detection applications in the sensor field.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Jiapu Li,Yuan Feng,Li Liang,Feng Liao,Wanxia Huang,Kuanguo Li,Guanglei Cui,Zewen Zuo
Flexible surface-enhanced Raman scattering (SERS) substrates are very promising to meet the needs for real-time and on-field detection in practical applications. However, high-performance flexible SERS substrates often suffer from complexity and high cost in fabrication, limiting their widespread applications. Herein, we developed a facile method to fabricate a flexible multicavity SERS substrate composed of a silver nanoparticle (AgNP)-decorated aluminum hydrous oxide nanoflake array (NFA) grown on a polydimethylsiloxane (PDMS) membrane. Strong plasmon couplings promoted by multiple nanocavities afford high-density hotspots within such a flexible AgNPs@NFA/PDMS film, boosting high SERS sensitivity with an enhancement factor (EF) of ∼1.54 × 109, and a limit of detection (LOD) of ∼7.4 × 10–13 M for rhodamine 6G (R6G) molecules. Furthermore, benefiting from the high sensitivity, high mechanical stability, and transparency of this substrate, in situ SERS detections of trace thiram and crystal violet (CV) molecules on the surface of cherry tomatoes and fish have been realized, with LODs much lower than the maximum allowable limit in food, demonstrating the great potential of such a flexible substrate in food safety monitoring. More importantly, the preparation processes are very simple and environmentally friendly, and the techniques involved are completely compatible with well-established silicon device technologies. Therefore, large-area fabrication with low cost can be readily realized, enabling the extensive applications of SERS sensors in daily life.
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ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Ying Yang,Xuebo Cao,Lin Huang,Quankun Li,Li Gu,Zheng Yan,Mengli Li,Ruobin Cheng,Zhufeng Lu,Ai-Jun Wang,Wenchao Yang
Electrochemical oxidization of crude ethylene glycol (EG) to fine chemicals driven by sustainable energy is an eco-friendly solution to the upcycling of end-of-life polyethylene terephthalate (PET) wastes. Here, pseudo Ag x -Pt y Pd z core–shell electrocatalyst capable of hybrid oxidation of EG to formate (FA) is designed and synthesized. The trimetallic system consists of Ag nanowire and ultrathin PtPd alloy skin with defects, such as holes and grooves. The defects expose the Ag core to the surroundings and convert Ag 0 to Ag 2+ active species at appropriate potential (> 1.2 V vs RHE). Thus, hybrid EG oxidization reaction is realized on the Ag x -Pt y Pd z electrocatalyst, where PtPd skin catalyzes EG oxidization through conventional Faradaic electrode process owing to inherent activities of Pt and Pd, while Ag 2+ serves as auxiliar oxidant to oxidize EG/intermediates (non-Faradaic reaction). Such a hybrid oxidization strategy reinforces the removal of adsorbates on Ag x -Pt y Pd z electrocatalyst and refresh the active sites timely. Eventually, ultrahigh specific activity (24.45 A mg −1 PtPd ) and long-term stability (> 3000 h at current density ≥ 400 mA cm −2 ) are delivered by the system. The finding of Ag 2+ -enhanced alcohol oxidization reactions introduces a new paradigm for designing high-performance electrocatalysts for energy and environmental applications.
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