LANGMUIR
·
2020
·
IF 3.557
Hui Hao,Yinliang Yang,Chao Zou,Wei Chen,Haihong Wen,Wei Wang,Yun Yang
Morphology of Ag nanocrystals (NCs) is essential to the NC application in catalysis, optics, and as antibacterial agents. Therefore, it is important to develop synthetic methods and understand the evaluation of NC morphology in different chemical environments. In this study, we report interesting findings of the morphological change of fivefold-twinned Ag–Au–Ag nanorods (NRs) under the effect of H2O2 both as an oxidant (etchant) and a reductant. At low H2O2 concentration, the reconstruction of Ag–Au–Ag NRs was dominated by the growth along the longitudinal direction of NRs. With the increase of H2O2 concentration, the reconstruction also occurs in the transverse direction, and a clear change in particle morphology was observed. We further systematically studied the mechanism of the reaction. The results showed that the transition of the morphology was a two-step process: (1) the etching of Ag on the seeds and (2) the reduction of Ag2O. In the second step, the reaction kinetics was highly affected by H2O2 concentration. At low H2O2 concentration, the growth mainly occurs along ⟨110⟩. However, at high H2O2 concentration, the reduction of Ag was not facet-selective. Using the developed method, we can prepare various bimetallic NCs (high aspect ratio NRs with abundant pinholes, nanoplates, and other NCs). The effect of the reconstruction process on the surface-enhanced Raman scattering (SERS) performance of NCs was investigated.
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高影响因子
JOURNAL OF FLUORESCENCE
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2020
·Vol. 30
·期 6
·1491-1498
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IF 2.093
Zhang Yuanyuan,Xu Hedan,Chen Yan,You Xiaoshuang,Pu Yunxun,Xu Wenfeng,Liao Xiaoling
Gold nanoclusters (AuNCs) stabilized by glutathione (GSH) have been synthesized using a simple one-pot method, which were used as a fluorescence-enhanced probe for the detection of cysteine (Cys) and GSH. The detection is based on the finding that the weak yellow fluorescence of the AuNCs, with excitation/emission maxima of 430/600 nm, can be enhanced by Cys and GSH via NCs aggregation. This method is selective for Cys and GSH. According to the fluorescence enhancement, the detection ranges of AuNCs for Cys and GSH are 2.49 µM ~ 0.80 mM and 1.99 µM ~ 0.44 mM, with the detection limit of 0.42 µM and 0.27 µM, respectively. In addition, the probe has good anti-interference performance over other common biomolecules. Importantly, the probe is successfully used for the determination of Cys in human serum samples, displaying the potential application of the probe in the detection of biological sulfhydryl molecules in actual samples.
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高影响因子
JOURNAL OF CLUSTER SCIENCE
·
2020
·Vol. 32
·期 5
·1371-1379
·
IF 1.731
Zhang Yingzhen,Song Yingying,Li Yancai
A simple and environment-friendly autocatalytic reduction process was developed for synthesis of Au/Ni(OH) 2 nanocomposites. The nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found the nanocomposites are composed of ultrathin Ni(OH) 2 nanosheets and gold nanoparticles (AuNPs), and the AuNPs disperse evenly on the Ni(OH) 2 nanosheets. The electrochemical and electrocatalytic properties of the Au/Ni(OH) 2 modified glassy carbon electrode (Au/Ni(OH) 2 /GCE) were investigated by electrochemical experiments. Furthermore, through optimizing Au loading of the nanocomposites, the 5%-Au/Ni(OH) 2 /GCE displays the best electrocatalytic activity towards glucose oxidization in alkaline medium. Under optimal conditions, the 5%-Au/Ni(OH) 2 /GCE displays a wide linear range of 0.01 to 3.15 mM (R 2 = 0.998) to glucose. Besides, the sensor has a low detection limit of 0.10 μM (S/N = 3) and a high sensitivity of 342.1 μA·mM −1 ·cm −2 . It also displays satisfying stability, good reproducibility and selectivity.
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ACS Applied Nano Materials
·
2020
·
IF 0
Shuyun Meng,Ningning Zhang,Dong Liu,Xiuli Shen,Yuye Li,Fan Jia,Yang Yang,Tianyan You
The widespread introduction of Cry1Ab protein in genetically modified crops has aroused considerable concern about the risks on the environment and food safety. Herein, we reported a plasmonic enhanced photoelectrochemical (PEC) immunosensor for the precise determination of the Cry1Ab protein. Its working principle was based on the space confinement-induced surface plasmon resonance to enhance visible-light absorption of photoactive materials. The polyamidoamine (PAMAM) dendrimers were selected as the space-confined template to synthesize gold (Au) nanoparticles, that is, PAMAM–Au, which presented smaller diameter and good dispersive stability. Meanwhile, PAMAM–Au nanocomposites can exhibit significantly enhanced surface electric field intensity according to the finite-difference time-domain analysis. Further, the efficient PEC enhancement of PAMAM–Au was then validated by the highly increased photocurrent in CdSe/PAMAM–Au nanocomposites. The as-fabricated PEC immunosensor provided a wide linear range of over 4 orders of magnitude (0.01–100 ng mL–1), with the detection limit down to 3 pg mL–1 for Cry1Ab analysis. Besides, such an immunosensor was applied to analyze Cry1Ab in corn and wheat samples, and the result was in good agreement with that by the official method, enzyme-linked immunosorbent assay. Our work provides a way to fabricate high-performance sensors for the accurate detection of Cry1Ab in the environment and food products.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2020
·
IF 3.232
Abid Hussain,Hongbin Pu,Bingxue Hu,Da-Wen Sun
Surface-enhanced Raman spectroscopy based on thioglycolic acid (TGA) functionalized silver-coated gold nanoparticles (Au@Ag-TGANPs) was developed for the facile screening of thiabendazole (TBZ) and ferbam (0.025–10 ppm) in liquid milk for the first time. Results showed that silver-coated gold nanoparticles (Au@AgNPs) with a core size of 32 nm and a shell thickness of 5 nm was successfully modified with 3 nm TGA. The sensitive Au@Ag-TGANPs could enhance TBZ and ferbam signals by factors of 6.4 × 10 4 and 9.8 × 10 4 , respectively, and achieved the detection of TBZ and ferbam with limits of detection of 0.12 and 0.003 ppm, R 2 of 0.988 and 0.9821, percent recoveries of 88–103% and of 87.2–103.5%, and relative standard deviations of 4.1–9.2% and 3.5–8.3%, respectively. The current simple and green method could thus be used to detect other unsafe chemicals in future studies.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Shikang Yin,Linlin Sun,Yaju Zhou,Xin Li,Jinze Li,Xianghai Song,Pengwei Huo,Huiqin Wang,Yongsheng Yan
The use of semiconductor photocatalytic reduction technology has higher efficiency and lower energy consumption for CO 2 reduction, but its existence of some mismatched energy band positions and relatively slow charge-hole separation greatly limits its practical application. In this paper, a SnS 2 /Au/g-C 3 N 4 embedded structure model with carbon and nitrogen hybridization is proposed to gain an in-depth understanding of the role of hybridization and precious metal modification in photocatalysis. Carriers were investigated from the perspective of kinetics through photocurrent, LSV curve, and FL spectroscopy. After modification of Au nanoparticles, the photo-excited electrons showed a slower decay process, indicating that the separation of carriers was enhanced, which was further confirmed by impedance and PL spectroscopy. SEM, AFM and TEM analysis confirmed that the 2D face-to-face SnS 2 /Au/g-C 3 N 4 embedded structure was successfully prepared and the Au nanoparticles were evenly distributed. Au nanoparticles not only act as a bridge for electron transport in 2D semiconductor materials to accelerate electron transport, but generate more excited electrons by themselves under the radiation of sunlight, which effectively improves the separation efficiency of electron-hole pairs and enhances the photocatalyst activity. DFT calculations show that the Z-type mechanism and the intercalated energy level of the SnS 2 /Au/g-C 3 N 4 embedded structure expand the light absorption and improve the carrier separation efficiency. As expected, the photocatalyst activity with CO and CH 4 the evolution rate of up 93.81 µmol·g −1 ·h −1 and 74.98 µmol·g −1 ·h −1 under visible light irradiation, respectively, while the photocatalytic activity is negligible loss after 30 h photoreduction. This work reveals the role of embedded structure and precious metal modification in the separation and transmission of electron-hole, opening up new perspective for achieving high-efficiency solar CO 2 reduction performance.
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Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 22
·7552-7560
·
IF 7.059
Se Shi,Anran Li,Renliang Huang,Jing Yu,Shuzhou Li,Wei Qi,Zhimin He,Rongxin Su
Highly functionalized materials at the nanoscale on optical fibers offer notable opportunities to construct “lab-on-fiber” functional devices with unusual properties. However, it is extremely difficult to fabricate nanostructures with special morphology on a thin cylindrical optical fiber surface using the commonly used physical lithography techniques. Meanwhile, it is vital to maintain the plasmonic properties of Ag-riched particles while improving their stability. Herein, we design a facile strategy for the fabrication of Au–Ag bimetallic nanorings (Au–Ag NRs) immobilized on optical fibers for enhanced plasmonic properties. Ag NPs are first grown in situ on an optical fiber surface through chelation and redox of polydopamine (PDA) to metal ions, and then are quickly converted into Au–Ag NRs by a galvanic replacement reaction and metal deposition. This conversion only takes 3.5 min, while the formed Au–Ag NRs exhibit outstanding localized surface plasmon resonance (LSPR) sensitivity (2204 nm per RIU) and oxidation resistance, and Au and Ag atoms are distributed uniformly in the nanorings. Furthermore, a novel and interesting formation process of the nanorings including deformation, spallation, growth in the gaps, and ring formation is studied. These findings provide a way to grow bimetallic nanorings on optical fibers, which are promising candidates for photoelectric “lab-on-fiber” devices.
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Scientific Reports
·
2020
·Vol. 10
·期 1
·1-9
·
IF 3.998
Zhang Lei,Weng Yi-jin,Liu Xiao,Gu Wen,Zhang Xia,Han Lei
Surface Enhanced Raman Scattering (SERS) has been widely applied in many research fields such as biological detection and chemical analysis. However, for the common Au nanoparticles, it’s too hard to guarante the three aspects: the great enhanced effect, the controllable aggregation and the uniformity of nanoparticles, the environmental friendliness and biocompatibility of nanoparticles. In this paper, phytate acid (IP6)-coated Au nanoparticles (IP6@Au NPs) are more stable and have a higher enhancement factor than Au nanoparticles. In order to achieve the uniformity of the spherical IP6-coated@Au nanoparticles (IP6@Au NPs), IP6 was used as a soft template. In the presence of IP6, IP6@Ag nanoparticles were first synthesized by reducing AgNO 3 with trisodium citrate, then IP6@Au NPs were obtained by reducing HAuCl 4 with Ag nanoparticles. The IP6@Au NPs exhibit excellent Raman signal enhancement by using p-aminothiophenol (4-ATP) as the probe molecules. The effects of Fe 3+ on the performance of IP6@Au NPs SERS substrates were also studied. The results show that SERS has the best enhancement effect when adding proper amount of Fe 3+ (0.56 PPM), and the limit of detection was 10 −7 M 4-ATP.
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高影响因子
ANALYTICAL BIOCHEMISTRY
·
2020
·
IF 2.877
Xiaodong Cao,Zihao Xia,Wuwen Yan,Shudong He,Xuan Xu,Zhaojun Wei,Yongkang Ye,Haisong Zheng
In this paper, we present a simple and label-free colorimetric biosensor for detection of the nopaline synthase (NOS) terminator in genetically modified (GM) plants. The “signal on” colorimetric biosensor was developed using a nanocomposite consisted of gold nanoparticles doped magnetic Fe 3 O 4 nanoparticles (Fe 3 O 4 @Au NP), capture probe DNA (cDNA), and hemin-functionalized reduced graphene oxide nanosheets (H-GN). The nanocomposite was successfully prepared by means of Au–S bonds and the strong π interactions between cDNA and H-GN. The sensing approach is based on the excellent peroxidase-mimicking activity of H-GN and its different electrostatic interactions with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). In presence of the target NOS, the cDNA in the nanocomposite will hybridize with its complementary sequence, and form dsDNA structure. Due to the weak π interactions between dsDNA and H-GN, a portion of H-GN will be released from the surface of Fe 3 O 4 @Au NPs and transferred into solution. After magnetic separation was performed, the supernatant was incubated with 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . The released H-GN can catalyze the oxidation reaction of TMB and turn the colorless solution blue. This “signal-on” colorimetric biosensor shows a broad linear range of 0.5–100 nM for the target NOS, with a 0.19 nM detection limit. The application of the biosensor for determination of NOS segments in samples of GM and non-GM tomatoes shows that it can discriminate between GM and non-GM plants. The reliability of the method for samples of NOS-spiked GM tomato suggests satisfactory recoveries in the range of 93.6%–94.2%.
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高影响因子
BIOSENSORS & BIOELECTRONICS
·
2020
·
IF 10.257
Tao Liu,Qiang Zhao,Ying Xie,Danfeng Jiang,Zhenyu Chu,Wanqin Jin
Currently, the large-scale and controllable fabrication of nanostructures on substrates remains a great challenge for further practical applications. In this work, a novel 3D aloe-like Au–ZnO nanocomposite was designed for in situ synthesis on an ITO substrate, achieving real-time detection of trace catechol (CC) in water. A seed-assisted hydrothermal approach was proposed to control the crystal distribution and growth direction to build a ZnO aloe-like architecture. To eliminate the natural weak conductivity of ZnO, Au nanoparticles were further deposited on all ZnO arrays to construct Au–ZnO micro/nanostructures. The synergetic effects derived from the aloe-like ZnO with a large specific area and Au nanoparticles with high conductivity resulted in both high electrocatalysis and fast electron transfer in enzymatic reactions . After laccase immobilization , the as-prepared biosensor exhibited specific recognition of catechol among other dihydroxybenzenes and phenol with an ultrahigh sensitivity of 131 μA mM −1 , as well as an extremely wide linear range from 75 nM to 1100 μM and an ultralow detection limit of 25 nM. In addition, in the detection of real lake samples, this biosensor showed satisfactory anti-interference ability and provided reliable assay results.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Zhen Qin,Hang Sun,Yanan Tang,Zhiyong Chang,Shengyan Yin,Zhenning Liu
Inspired by the characteristics that plant leaves are beneficial for solar light absorption, we have prepared a bio-inspired hierarchical assembly of carbonized spinach leaves@Au/ZnO (CS@Au/ZnO) for solar energy utilization. CS@Au/ZnO shows a low light reflectance of 5% and a high specific surface area of 311.41 m 2 /g. CS@Au/ZnO demonstrates higher photocatalytic degradation efficiency: more than 97% of Rhodamine B (RhB) and 61% of ciprofloxacin (CIP) could be degraded in 180 min under the visible light irradiation. In addition, we also tested the photocatalytic H 2 production performance of CS@Au/ZnO and the H 2 evolution rate is 2.384 mmol g −1 h −1 under simulated solar light. CS@Au/ZnO shows a high cycling stability in recyclable photocatalytic degradation and photocatalytic water splitting. Moreover, CS@Au/ZnO shows a swift and steady photocurrent of about 63.6 μA/cm 2 , illustrating a high sensitivity to solar light. The enhanced photocatalysis performance of CS@Au/ZnO could be ascribed to the naturally optimized macroporous structure of CS with high conductivity, which could enhance the light harvesting and carrier transport, simultaneously. Moreover, modification of AuNPs can broaden the light response range of ZnONRs and reduce the probability of electron-hole recombination. Due to the wide availability of plant leaves, CS@Au/ZnO assembly has broad application prospects in photocatalytic degradation of organic pollutions, photovoltaic devices , and photocatalytic H 2 evolution.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Weiwei Lu,Fengyang Ju,Kaisheng Yao,Xuefeng Wei
Conversion of CO2 into value-added fuels and chemicals faces the challenges of high overpotential, low selectivity for desired products, and sluggish multi-electron transfer kinetics. Plasmon-mediated electrocatalytic methods show potential for overcoming these problems. In this work, choosing Au nanoparticles (NPs) as the dual-functional material of the electrocatalyst and plasmonic support, methanol can be efficiently produced from CO2 reduction. The dependences of current density and Faradaic efficiency (FE) on the Au NP size, light wavelength, and light density are systematically investigated. The performance test results show that CH3OH with FE as high as 52% can be obtained at a potential of −0.8 V (vs RHE) when a 20.2 nm Au NP-modified glass carbon electrode is under excitation using 520 nm light with a light density of 120 mW/cm2. The performance results, along with the discrete dipole approximation calculation and electrochemical characterizations, suggest that the efficient activation of CO2 by plasmon-generated energetic electrons accounts for the enhanced conversion rate and the high selectivity for CH3OH production.
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