INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Jian Zhang,Kai Shi,Zhe An,Yanru Zhu,Xin Shu,Hongyan Song,Xu Xiang,Jing He
Dehydrogenation coupling of ethanol to n-butanol has received much attention due to the wide application of n-butanol. Highly selective butanol production from ethanol remains a challenge due to competitive reactions in the dehydrogenation and/or condensation and great difficulty in ethanol dehydrogenation. This work reports a synergistic catalysis between layered double hydroxide (LDO), an acidic–basic support, and supported Ag particles for the dehydrogenation coupling of ethanol to n-butanol. A selectivity of up to 77% toward n-butanol with an ethanol conversion of 23.2%, among impressive levels reported till now, has been achieved at 350 °C, 0.1 MPa. A selectivity of up to 60% toward n-butanol with an ethanol conversion of 45%, the highest selectivity at an ethanol conversion of >45% reported till now, has been achieved at 250 °C, 2 MPa. A synergistic catalysis between the acid–base sites of the LDO surface and supported Ag particles have been revealed to contribute the excellent butanol selectivity: basic sites promote adsorption and subsequent dehydrogenation of ethanol on Ag particles; in addition to the promotion from Ag, the following aldol condensation is boosted by acid–base cooperation.
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Materials Research Express
·
2020
·Vol. 7
·期 2
·025027
·
IF 1.929
Hong Zhao,Diandian Liu,Shujuan Xu,Yao Chen,Fujun Yin,Tao Yang,Mingyan Wang,Hua Deng,Wei Zhang,Weiwei Liu,Xiaohong Liu
Active electrocatalysts are the key to water splitting for hydrogen production through the electrolysis. In this paper, 50 nm silver nanoplates were used as templates for synthesis of Au–Ag island-shaped nanoplates by controlling the surface chemistry. The guiding mechanism of polyvinylpyrrolidone (PVP, Mw = 40 000) to Au–Ag island-shaped nanoplates crystal was also further investigated. It is found that the surface energy of Ag nanoplates between (100) and (111) crystal planes can be regulated by varying the amount of PVP in the system. Then a uniform Au-Ag triangular island nanostructure was obtained. Compared with the Ag nanoplates catalysts, the Au–Ag island nanoplates catalysts show the superior catalytic performances in hydrogen evolution electrocatalysis (HER). These results demonstrate a new surface chemistry modification by PVP and a galvanic displacement reaction for designing the active electrocatalysts. More importantly, the Au–Ag island-shaped nanoplates show an unconventional growth mode of preserving the original Ag nano-triangular crystal structure. The enhanced performance in electrocatalysis can be mainly attributed to Au–Ag alloy structure, which allows the appearance of synergistic effects. The present work demonstrates the crucial roles of surface chemistry in catalysts synthesis, which may guide the design of active bimetallic catalysts.
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CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
P. Ning,C.C. Liu,Y.J. Wang,X.Z. Li,R. Ranjithkumar,Z.H. Gan,Y.Y. Wu,T. Fu
Magnetic MnFe 2 O 4 nanoparticles containing 0, 1 and 3 at.% silver, respectively were synthesized by one-pot sol-gel method for antibacterial applications in biomedical fields. Material characterizations indicate that MnFe 2 O 4 begins crystallization at 134 °C and oxidation at 450 °C, the grain size and agglomeration degree increase with the silver content and silver exists as metallic state for the particles. The saturation magnetization decreases with the sintering temperature and slightly increases with the silver content, with the maximum of 50.0 emu/g obtained. Antibacterial tests by plate counting and PI-Hoechst 33342 staining suggest that the antibacterial activity of Ag–MnFe 2 O 4 nanoparticles is silver content-dependent. Silver ions concentration measurement, β-galactosidase activity assay and transmission electron microscopic observation show that the antibacterial activity is dominated by the actions of the released silver ions, rather than the membrane cell impairment or reactive oxygen species-induced oxidative stress mechanism. MC3T3-E1 cell test demonstrates the best cytocompatibility of the nanoparticles with 3 at.% silver, which is likely related to the reduced cell endocytosis of the aggregated particles. The combination of magnetism , antibacterial activity and biocompatibility would make Ag–MnFe 2 O 4 nanoparticles a potential multi-functional material in various biomedical applications.
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RSC Advances
·
2019
·Vol. 9
·期 2
·878-883
·
IF 3.049
Fangke Zhan,Ran Wang,Juanjuan Yin,Zengsheng Han,Lun Zhang,Tifeng Jiao,Jingxin Zhou,Lexin Zhang,Qiuming Peng
Functional nanocomposites demonstrate excellent comprehensive properties and outstanding characteristics for numerous applications. Magnetic nanocomposites are an important type of composite materials, due to their applications in optics, medicine and catalysis. In this report, a new Fe3O4-loaded silver (Fe3O4–Ag) nanocomposite has been successfully synthesized via a simple solvothermal method and in situ growth of silver nanowires. The silver nanowires were prepared via the reduction of silver vanadate with the addition of uniformly dispersed Fe3O4 nanoparticles. Structural and morphological characterizations of the obtained Fe3O4–Ag nanocomposite were carried out using many characterization methods. As a new composite catalyst, the synthesized magnetic Fe3O4–Ag nanocomposite displayed a high utilization rate of catalytically active sites in catalytic reaction medium and showed good separation and recovery using an external magnetic field. The facile preparation and good catalytic performance of this Fe3O4–Ag nanocomposite material demonstrate its potential applications in catalytic treatment and composite materials.
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高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Shanshan Wang,Yingyi Wang,Yi Peng,Xiaoming Yang
Integrating kinds of bactericides as one entirety shows prospect for improving antibacterial efficiency, thus a new type of nanoclusters based on bactericide-directed herein emerged as a combination for achieving a higher antibacterial effect. Specifically, an easily operated approach for preparing bacitracin-directed silver, gold, and copper nanoclusters (AgNCs, AuNCs, and CuNCs, respectively) was proposed. Meanwhile, AgNCs@Bacitracin, AuNCs@Bacitracin, and CuNCs@Bacitracin emitted cyan, yellow, and red colors of fluorescence, respectively, and different sizes and nitrogen contents of these nanoclusters played a critical role for their fluorescence alterations. Significantly, AgNCs@Bacitracin exhibited robust bacteria-killing efficiency than other nanoclusters, owing to its marked damage on the bacterial membrane. Additionally, propidium iodide (PI) staining indicated the bacterial membrane damage of 72.3% to the bacteria population followed by the treatment with AgNCs@Bacitracin, and the introduction of AgNCs@Bacitracin lead to the higher reactive oxygen species (ROS) production, facilitating their attractive antibacterial activity. Moreover, this strategy of developing new nanoclusters broadened the avenues for designing the improved antibacterial materials.
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COMPOSITES PART B-ENGINEERING
·
2019
·
IF 6.864
Ying Huang,Wei Hu,Xinli Wang,Xiaohui Guo,Chao Hao,Yunong Zhao,Xiao Zeng,Ping Liu
A phase transition-controlled force actuator based on graphene/Ag/SR (silicone rubber) has been designed and fabricated. This actuator is based on the principles of phase transition. The actuator with an enclosed cavity, which consisted of a latex film and a graphene/Ag/SR-based electrothermal substrate, and then injecting ethanol into the cavity. The actuator can operate at a low voltage (6 V), and the magnitude of the feedback force can be controlled by applying a square wave signal which the duty cycle is adjustable. The minimal change in feedback force is 0.02 N. Owing to its simple fabrication, easy operation, lightweight (1.4 g), low driving voltage , large deformation and controllable force, manipulator, auto-injector and bionic fish have been made. Summarizing aforementioned experimental results, the manipulator can grip objects of different weights, and the auto-injector can inject a liquid and act as an injector . Furthermore, bionic fish can float and sink in the water. These devices showing that the phase transition actuator is expected to be widely used in soft robots , bionic devices design, and medical field. Also, this category of phase transition actuator could provide ideas for developing flexible actuator.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Rong Wang,Liping Zhang,Shiying Zou,Hong Zhang
In this paper, novel Ag nanodendrites (Ag NDs) substrates were designed and fabricated on indium tin oxide (ITO) glass by using cyclic voltammetry electrodeposition. This method was simple, facile and controllable without any seed, template or surfactant. The influence of electrodeposition conditions on the microstructure and SERS-active of Ag NDs substrate were studied. Under the optimized conditions, the as-prepared Ag NDs exhibited superior SERS activity toward malachite green(MG) with high enhancement effect of 5.4 × 10 9 and low detection limit of 9.4 × 10 −13 M. Moreover, the Ag-NDs substrate shows extremely good uniformity and reproducibility with low relative standard deviation of 12.6% for substrate-to-substrate. In addition, a logarithmic correlation between MG concentration and Raman intensity was obtained, with the linearly dependent coefficient (R 2 ) of 0.984. The as-prepared Ag NDs substrates were successfully applied to the determination of MG in environmental water, with recoveries in the range of 87.8% to 109.6%. These results show high potential of the Ag NDs as effective SERS substrates for rapid detection of other trace-level contaminants in environment water.
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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2019
·Vol. 28
·期 12
·7213-7226
·
IF 1.476
Yang Ming,Jia Zhengfeng,Pang Xianjuan,Shao Xin,Zhen Jinming,Zhang Ran,Ni Junjie,Jiang Jinlong,Yu Bo
In this paper, polydopamine/silver (PDA/Ag) nanoparticles were easily synthesized. Then, the PDA/Ag nanoparticles were sprayed on copper substrate and heat-treated under argon to get carbonized PDA/Ag (CPDA/Ag) composite films. Transmission electron microscopy, field-emission scanning electron microscopy, x-ray diffraction, Raman spectroscopy and x-ray photoelectron spectroscopy were employed to investigate the conversion of PDA and AgNO 3 into CPDA and Ag,
respectively. Results showed that the PDA/Ag composite films heat-treated at 500 °C had much better friction reduction and anti-wear properties than other samples. The tribofilms containing C, N, O, Ag and Cu played an important role on reducing friction and increasing wear resistance.
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Journal of the Taiwan Institute of Chemical Engineers
·
2018
·
IF 3.849
Junlei Zhang,Zhen Ma
Novel Ag-Ag 2 CO 3 /Bi 2 MoO 6 composites were obtained through in situ formation of Ag 2 CO 3 rods/nanoparticles onto Bi 2 MoO 6 nanosheets, followed by photoreduction. These composites were found to be much more active than Bi 2 MoO 6 in photocatalytic degradation of rhodamine B (RhB) under visible-light irradiation. In particular, an Ag-Ag 2 CO 3 /Bi 2 MoO 6 composite with a theoretical Ag 2 CO 3 /Bi 2 MoO 6 mass ratio of ∼27.5% exhibited the highest photocatalytic activity. It was also the most active in photocatalytic degradation of methyl blue (MB) and tetracycline hydrochloride (TC), due to the enhanced visible-light absorption and efficient separation of photogenerated carriers. The good reusability of Ag-Ag 2 CO 3 /Bi 2 MoO 6 was verified by cycling degradation experiments. The dominant active species were found to be photogenerated holes (h + ). A possible photocatalytic mechanism was proposed.
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CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Ke Li,Sisi Cui,Junli Hu,Yifa Zhou,Yichun Liu
Nanofibers with well-dispersed Ag nanoparticles (AgNPs) are promising for some applications. Dispersion electrospinning is a straightforward preparation method but is suffered from the negative effects that the further treatments of nanofibers after electrospinning may bring to the dispersed AgNPs. In this study, we report a post reduction method to fabricate nanofibers with well-dispersed AgNPs. Crosslinked nanofibers of a hydrophilic polysaccharide, pectin, are used. When being immersed in the aqueous solution of AgNO 3 , the crosslinked pectin nanofibers swell, allowing Ag + ions enter inside. The surrounding crosslinked pectin macromolecules functionalize as in situ reducing reagents to reduce Ag + ions, nucleating the crystallization of AgNPs locally. X-ray diffraction characterizations indicate that the formed AgNPs are face-centered cubic crystalline. Results of optical imaging, UV–vis spectroscopy, scanning electron microscopy (SEM), electron dispersive spectrometry as well as transmission electron microscopy (TEM) indicate that the content and size of AgNPs increase with the increase of AgNO 3 concentration and incubation time. SEM and TEM results show that the dispersion of the AgNPs does not affect the nanofibrous structure and size of the crosslinked pectin nanofibers. TEM results also demonstrate that AgNPs distribute homogeneously along both the length and diameter direction of nanofibers. The composite nanofibers can sustainably release silver for 4 weeks and inhibit the growth of Escherichia coli for 7 days, showing great potential as long-term antibacterial materials. The method may also be used to disperse AgNPs in other hydrophilic nanofibers which need further treatments after electrospinning.
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高影响因子
Chinese Physics B
·
2018
·Vol. 27
·期 8
·087308
·
IF 1.321
Hui-De Wang,David K Sang,Zhi-Nan Guo,Rui Cao,Jin-Lai Zhao,Muhammad Najeeb Ullah Shah,Tao-Jian Fan,Dian-Yuan Fan,Han Zhang
Black phosphorus (BP), an attractive two-dimensional (2D) semiconductor, is widely used in the fields of optoelectronic devices, biomedicine, and chemical sensing. Silver ion (Ag+), a commonly used additive in food industry, can sterilize and keep food fresh. But excessive intake of Ag+ will harm human health. Therefore, high sensitive, fast and simple Ag+ detection method is significant. Here, a high-performance BP field effect transistor (FET) sensor is fabricated for Ag+ detection with high sensitivity, rapid detection speed, and wide detection concentration range. The detection limit for Ag+ is 10−10 mol/L. Testing time for each sample by this method is 60 s. Besides, the mechanism of BP-FET sensor for Ag+ detection is investigated systematically. The simple BP-FET sensor may inspire some relevant research and potential applications, such as providing an effective method for the actual detection of Ag+, especially in witnessed inspections field of food.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2019
·
IF 3.973
Lingyan Yang,Liliang Chen,Yi-Chun Chen,Lei Kang,Jiantao Yu,Yuhang Wang,Chengjia Lu,Tsutomu Mashimo,Akira Yoshiasa,Chia-Hua Lin
Immiscible bimetallic Ag–Cu system has been synthesized by the pulsed plasma in liquid method with a graph of one pulse duration. Herein, by combining X-ray power diffraction, K-edge X-ray absorption near edge structure and high-resolution transmission electron microscopy, our results indicate that homogeneously alloyed Ag–Cu nanoparticles (Ag–Cu NAs) have the average diameter about 2.1 nm, composed by 48.5 at% Ag and 51.5 at% Cu with chemical analysis and the estimated lattice parameter was 3.873 Å. The antibacterial property of Ag–Cu NAs was detected against E. coli and S. aureus strains according to the colony formed abilities of bacteria on agar plates covered with the nanoparticles. With very short incubation period, Ag–Cu NAs completely inhibited the E. coli and S. aureus growth at an ultralow concentration. The mechanism of antibacterial property of Ag–Cu NAs was performed by the inductively coupled plasma-atomic emission spectrometry and the plane wave pseudopotential method implemented in the CASTEP package based on the density functional theory. The Ag + dissolution is correlated with antibacterial activity for Ag–Cu NAs-assisted antibacterial treatment. These findings obtained revealed that our Ag–Cu NAs could be served as a containing material of numerous bacteria-free products in order to avoid their bacterial contamination.
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