MICROPOROUS AND MESOPOROUS MATERIALS
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2020
·
IF 4.551
Peng Xu,Zhenguo Wu,Wei Dai,Yang Wang,Mengke Zheng,Xiaodan Su,Zhaogang Teng
Multiple Ag nanoparticles loaded hollow mesoporous carbon spheres (Ag@HMCSs) are successfully synthesized through a “soft-to-hard templating” approach. In this method, polyacrylic acid (PAA) colloids are used as stabilizers for Ag nanoparticles and serve as soft templates for a sol-gel process with tetraethyl orthosilicate and polymerization process of resorcinol-formaldehyde resin (RF resin) in one pot. Ag@HMCSs are obtained after carbonization of the RF resin layer and selectively etching the SiO 2 component. Ag@HMCSs exhibit a spherical morphology with a mean size of approximately 140 nm and a high surface area of 239.67 m 2 g −1 , and the average size of encapsulated silver nanoparticles are about 10 nm without aggregation. The prepared Ag@HMCSs show excellent catalytic activity and stability for reduction of 4-nitrophenol, Congo red, and Rhodamine B. Therefore, this “soft-to-hard templating” approach represents a promising strategy for the preparation of high-performance carbon nanoparticle-supported catalysts.
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Nanomaterials
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2020
·Vol. 10
·期 9
·1624
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IF 4.324
Haian Xia,Jiahuan An,Weizi Zhang
The metal–support interaction (MSI) has a remarkable effect on the catalytic properties, but how to precisely modulate its degree remains a huge challenge. Herein, polyvinylpyrrolidone (PVP) with three different molecular weights (MWs) (24, 58, and 130 kDa) was used as a capping agent to fabricate Ag nanoparticles (NPs) supported on ZrO2. The physiochemical properties of the catalysts were characterized by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), and Fourier transform infrared (FT-IR) techniques. The impacts of MSI on the catalytic activity and reaction kinetics for aerobic oxidation of 5-hydroxymethylfurfural (HMF) were investigated. The results showed that the introduction of PVP with various MWs could efficiently tailor the interfacial interactions and charge transfers (CT) among PVP, the support, and Ag NPs, thereby affecting the oxidation activity of HMF. The turnover number (TON) for HMF oxidation decreases in the order of unsupported colloidal Ag clusters > Ag/ZrO2(58,000) > Ag/ZrO2(130,000) > Ag/ZrO2(24,000) > Ag/ZrO2. The reason for this large difference in the catalytic activity for HMF oxidation is that various MWs of PVP result in a change of MSI, thereby facilitating CT from PVP to Ag metal sites. This study offers a new strategy for modulating MSI by varying the MW of capping agents, thereby tuning the catalytic properties in the oxidation of HMF.Keywords:metal–support interaction;molecular weight;capping agent;PVP;HMF oxidation
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2020
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IF 3.807
An-ran Zhang,Hui Zhong,Xiao-rong Li,Zhuan-li Bao,Zhi-peng Cheng,Yu-jie Zhang,Ping Chen,Zai-chao Zhang,Li-li Zhang,Hai-yan Qian
An electrochemiluminescence (ECL) sensor was developed with carboxylated graphene-loaded Au@Ag core-shell nanoparticles . Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM) and inductive coupling plasma (ICP) were applied to characterizing COOH-G/Au@Ag nanocomposites . Electrochemical performance of the nanocomposites was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Based on ECL experimental results, we can find COOH-G/@Au@Ag nanocomposites have good electrocatalytic ability for glucose, so we construct a glucose electrochemiluminescence (ECL) sensor. When the glucose concentration range is from 0.005 to 1500 μM, the linear response of ECL intensity to glucose concentration was valid with detection limit of 0.02 μM. In addition, the developed sensor not only has good stability, repeatability and sensitivity for the detection of glucose, but also can be successfully used for glucose monitoring in human serum samples.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Tong Wu,Hui Zheng,Yichuan Kou,Shilei Jin,Yuhong Jiang,Ming Gao,Lei Chen,Naveen Reddy Kadasala,Yang Liu
In this study, 3D Fe 3 O 4 micro-flowers were synthesized by the self-assembly approach, then rhombic dodecahedral Cu 2 O was successfully loaded onto their surface by wet chemical method . Ag nanocrystals were reduced in situ on the surface of Fe 3 O 4 /Cu 2 O composites to prepare novel Fe 3 O 4 /Cu 2 O/Ag composites. The composites were characterized by SEM, TEM, XRD , XPS, VSM and UV–Vis diffuse reflectance spectroscopy. The effect of Ag nanocrystals on the photocatalytic performance of the Fe 3 O 4 /Cu 2 O composites was investigated by the degradation of methyl orange under visible light irradiation, and the Fe 3 O 4 /Cu 2 O/Ag composites showed higher photocatalytic efficiency than the Fe 3 O 4 /Cu 2 O composites. Photoelectrochemical and PL measurements were carried out to investigate the synergistic effect between the semiconductors and Ag nanocrystals and it was confirmed that the Fe 3 O 4 /Cu 2 O/Ag composites effectively inhibited the recombination of electron-hole pairs, thus improving the photocatalytic activity. The fact that the Fe 3 O 4 /Cu 2 O/Ag composites could be magnetically recycled and that they retained more than 90% of their original activity after six repeated experiments indicates, that they show great potential for wastewater treatment applications.
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CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Shaosheng Rao,Yi Li,Hanqing Liu,Shuai Gao,Jinxia Zhao,Nasir Rahman,Jinghan Li,Yazhou Zhou,Ding Wang,Lili Zhang,Qinqin Liu,Juan Yang
Improving the efficiency of Ag nanoparticles (NPs) in an antibacterial system remains a problem to be solved. Herein, a simple polyethyleneimine (PEI) modification strategy has been developed for realizing the high dispersion of Ag NPs with average size of 10 nm over two dimensional nanosheets of g-C 3 N 4 photocatalyst , and the as-prepared ternary Ag/PEI/CN hybrid demonstrates enhanced bifunctional performance of antibiotics (e.g., tetracycline, TC) degradation and antibacterial activity. The enhanced mechanism is investigated and proposed to be a synergy effect between reactive oxygen-containing species (ROS, e.g., •OH and O 2 •− ) derived from PEI modified g-C 3 N 4 photocatalyst and slow released Ag + ions generated by the highly dispersed Ag NPs as antimicrobial agent. Furthermore, the surface plasmonic effect of Ag NPs and coupling of PEI can increase light absorption and accelerate the electron-hole separation and mobility. Consequently, more availability of ROS along with holes and Ag + ions can accelerate the death of bacteria via destructing biomolecules. As a result, under visible-light irradiation, Ag/PEI/CN hybrid presents greatly improved antibacterial activity against E. coli , including a low MIC 100% of 30 ppm and MBC 97% of 10 ppm and enhanced photocatalytic performance towards TC degradation (~80% TC can be degraded within 60 min).
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MICROCHIMICA ACTA
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2020
·Vol. 187
·期 8
·1-7
·
IF 6.232
Sun Ye,Zhang Yao,Wang Yue,Xia Lixin
A new sensor for determination of Ag + ion (Ag + ) by surface-enhanced Raman scattering (SERS) is reported. Gold nanoparticles (AuNPs) and 4-aminodiphenyl disulfide (APDS) were chosen as the SERS substrate and probe molecule, respectively. With the addition of Ag + , three new peaks (1141, 1392, and 1435 cm −1 ) appeared in the SERS spectrum, indicating that the conversion of APDS to p , p ′-dimercaptoazobenzene (DMAB) was achieved. As the concentration of Ag + increased, the conversion of APDS to DMAB also increased and showed a good linear relationship ( R 2 = 0.9746) in the range of 10 to 100 μM of Ag + . The limit of detection (LOD) was 7 μM. Compared with the traditional determination method, the SERS method is convenient and fast and requires no complicated preprocessing.
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ORGANIC ELECTRONICS
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2020
·
IF 3.31
Rongmei Yu,Furong Yin,Chunying Pu,Haizhen Song,Xiumei Xu,Han Zhang,Wenyu Ji
Although much effort has been made to the cadmium-free quantum dot light emitting diodes (QLEDs), it is still a big challenge to achieve an efficient eco-friendly QLED. Here, an extremely efficient QLED based on Ag–In–Zn–S QDs is constructed with the insertion of an 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi) hole-spacing interlayer. The electrical properties of single carrier devices demonstrate the TPBi blocks the hole injection, leading to a more balanced charge injection in the device. Transient electroluminescence measurements confirm that the hole accumulation adjacent QDs is dramatically suppressed after the insertion of TPBi, hence limiting the interactions between excitons and holes. Consequently, the peak current (power) efficiency of 6.0 cd/A (6.5 lm/W) is achieved. To the best of our knowledge, this is the record efficiency for the Ag–In–Zn–S QLEDs reported to date. We anticipate this work will provide a new route for optimizing the performance of Cd-free QLEDs.
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SENSORS AND ACTUATORS B-CHEMICAL
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2020
·
IF 7.1
Qingwen Zhang,Danfeng Jiang,Changshun Xu,Yuancai Ge,Xiaohu Liu,Qingquan Wei,Liping Huang,Xueqian Ren,Chengde Wang,Yi Wang
We proposed a wearable electrochemical biosensor based on Ag Nanowires (AgNWs) and molecularly imprinted polymers (MIPs) prepared on the screen-printed electrode for the noninvasive monitoring of lactate in the human sweat. The MIPs were prepared by electropolymerization of 3-aminophenulboronic acid (3-APBA) with imprinted lactate molecule on the AgNWs-coated working electrode. The MIPs-AgNWs biosensor revealed high sensitivity and specificity for the detection of lactate from 10 −6 M to 0.1 M, with the detection limit of 0.22 μM. Furthermore, the sensors presented high stability and reproducibility with sensitivity recovery of 99.8% ± 1.7% during 7 months storage in a dark plastic box at room temperature. In addition, the flexible electrodes also showed stable electrochemical response after been bended and twisted for 200 times, respectively. Such MIPs-AgNWs biosensor was attached on volunteers’ skin for the noninvasive monitoring of the perspiration lactate in vivo . The wearable electrochemical biosensor provides feasibility in near future for the evaluation of human sweat in the military, sports and biomedical fields.
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ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Ting Zhou,Min Fan,Ruiyun You,Yudong Lu,Luqiang Huang,Yunchao Xu,Shangyuan Feng,Yang Wu,Huiying Shen,Lanjin Zhu
We have successfully prepared a highly sensitive sandwich nanosensor combined Fe 3 O 4 and [email protected] @Ag nanorods for histamine detection based on surface-enhanced Raman spectroscopy (SERS). The Fe 3 O 4 beads with –COOH served as a capture part to enrich histamine. The [email protected] @Ag core-shell nanorods functionalized with Nalpha,Nalpha-Bis(carboxymethyl)- l -lysine (AB-NTA) were then used to connect with the imidazolyl group of histamine, simultaneously the internal standard 4-aminothiophenol (4-ATP) in the core-shell structure was used as the SERS signal. PLS regression model based on concentration range 10 −3 -10 −8 mol/L showed a linear trend with R 2 = 0.9907. Our new approach can quickly and reliably determine histamine in fish sample and RAW264.7 cell lysates. This protocol for histamine extraction and SERS analysis enables the development of ultra-sensitive method for histamine detection.
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Advanced Composites and Hybrid Materials
·
2020
·Vol. 3
·期 3
·402-414
·
IF 0
Liu Chao,Lin Yang,Dong Yufei,Wu Yingke,Bao Yan,Yan Hongxia,Ma Jianzhong
In this paper, a novel Ag nanowires/TiO 2 nanosheets/graphene nanocomposite was fabricated via a facile method of hydrothermal and calcination, and then the water treatment performance of it was evaluated for methylene blue (MB) and Escherichia coli removal. The as-prepared Ag nanowires/TiO 2 nanosheets/graphene nanocomposite was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), UV–visible diffuse reflection spectroscopy (DRS), molecular dynamics simulation, and gas chromatography–mass spectrometry (GC-MS). All data revealed that the Ag/TiO 2 /graphene nanocomposite showed a rich cell structure. The photocatalytic activity of Ag/TiO 2 /graphene nanocomposite is higher than those of pristine TiO 2 nanosheets and TiO 2 /graphene nanocomposite. Under optimized conditions, the degradation efficiency was 100% and 71% for MB (30 mg/L) and with 10 mg Ag/TiO 2 /graphene nanocomposite under UV and visible light irradiation for 2 h, respectively. Ag/TiO 2 /graphene also showed excellent bacteria-killing activity. Meanwhile, the Ag/TiO 2 /graphene nanocomposite exhibited microstructure stability and cyclic stability. The water treatment performance was enhanced mainly attributed to the excellent adsorption performance of graphene and the high efficiency in separation of electron–hole pairs induced by the remarkable synergistic effects of TiO 2 , Ag, and graphene. On the basis of the experimental results, the photocatalytic mechanism and MB degradation mechanism were proposed. It is hoped that our work could avert the misleading message to the readership, hence offering a valuable source of reference on fabricating composite photocatalyst with stable microstructure and excellent performance for their application in the environment clean-up.
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MICROCHEMICAL JOURNAL
·
2020
·
IF 3.594
Xiu-Fang Huang,Bing-Xue Ren,Chi-Fang Peng,Xin-Lin Wei,Zheng-Jun Xie
In this study, the fluorescence enhancement effect of guanine base on DNA-Cu/AgNCs was reported and fluorescent methods for the determination of Hg 2+ or Cu 2+ ion were established. The effect of adjacent and inserted guanine base (G) sequences in DNA template on the fluorescence intensity of DNA-Cu/AgNCs was investigated. It was found that G 5 sequence extended from the 5′ end of a typical C-riched DNA strand, 5′-CCCTTAATCCCC-3′ (DNA1), demonstrated fluorescence enhancement effect in the preparation of the DNA-Cu/AgNCs. Moreover, this G5-DNA-Cu/AgNCs can be used to determine Hg 2+ and Cu 2+ ions due to fluorescence quenching by the two metal ions while the DNA1-Cu/AgNCs only can determine Hg 2+ ions. Specific assays for Hg 2+ ions and Cu 2+ ions were established through masking Cu 2+ ions by EDTA and Hg 2+ ions by NaBH 4 , respectively. In Hg 2+ determination, a linear range from 5.0 nM to 40 nM was obtained with a detection limit of 1.0 nM. In Cu 2+ determination, a wide linear range from 0.01 µM to 5.0 µM was obtained with a detection limit of 5.0 nM. The recoveries of 89.6–106.8% for Cu 2+ ions and 90.6–106.2% for Hg 2+ ions were obtained in the measurements of Hg 2+ and Cu 2+ ions spiked lake samples, respectively. The results indicate the potential application of the DNA-Cu/AgNCs as a metal ions probes in real samples.
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 26
·11076-11084
·
IF 3.288
Yin'an Zhu,Ye Pan,Enming Zhang,Weiji Dai
Hetero-junctions are widely considered as efficient and promising separators for photogenerated electron–hole pairs in photocatalytic processes. In this work, a self-assembled urchin-like TiO2@Ag–CuO hetero-junction was fabricated via a two-step approach combining a dealloying method with calcination using alloy ribbons as the precursors. This nanostructure exhibits enhanced degradation efficiency toward tetracycline hydrochloride (TC) under visible light irradiation, achieving a degradability of 82.86% after 3 hours, higher than those of P25, CuO, TiO2@Ag and TiO2@CuO binary hetero-junctions. The photocurrent response and electrochemical impedance spectroscopy studies reveal that the TiO2@Ag–CuO hetero-junction possesses an excellent separation ability and a long lifespan with regard to photogenerated electron–hole pairs, which may contribute to its enhanced photocatalytic ability. In addition, this unique nanostucture maintained good degradation stability even after four-cycle utilization. The findings of this work provide new ideas to prepare multicomponent hetero-junctions for water purification.
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