Nanoscale
·
2019
·Vol. 11
·期 45
·21990-21998
·
IF 6.97
Huali Liu,Zhen Li,Yan Yan,Jiaqi Zhao,Yu Wang
The coupling between noble metal nanostructures and chiral molecules gives rise to strong chiroptical responses in the range from the ultraviolet (UV) to visible spectrum. In this work, cysteine-modified Au/Ag alloyed nanotubes (ANTs) have been prepared by coupling cysteine with Au/Ag ANTs. The chiroptical responses strongly depend on the chirality of cysteine and show clear mirrored behaviours. In contrast to Ag- or Au-cysteine chiral hybrid nanorods, the cysteine-modified Au/Ag ANTs exhibit higher chiroptical responses due to a stronger local electromagnetic field. The induced CD signals emerge in the interband absorption region of Au/Ag ANTs rather than in the local surface plasmon bands, which can be attributed to both the extended helical network conformation on the surface of Au/Ag ANTs and the near-field enhancement effect of plasmonic nanotubes. This confirms that Coulomb interaction induces coupling between cysteine and Au/Ag ANTs, which allows cysteine molecules to form an extended helical network on the surface of Au/Ag ANTs. Furthermore, the cysteine-modified Au/Ag ANTs also show excellent chiral recognition for amino acids in catalytic electrochemical reactions due to the presence of chiral active sites and the steric effect of large groups.
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RSC Advances
·
2019
·Vol. 9
·期 26
·14982-14989
·
IF 3.049
Pian Wu,Ping Ding,Xiaosheng Ye,Lei Li,Xiaoxiao He,Kemin Wang
Multimetallic nanomaterials have aroused special attention owing to the unique characteristics of chemical, optical and enhanced enzyme mimetic capabilities resulting from the synergistic effect of different metal elements. In this work, we present a facile, gentle, fast and one-pot method for preparing Cu/Au/Pt trimetallic nanoparticles (TNPs), which possess intrinsic and enhanced peroxidase-like activity as well as excellent stability, sustainable catalytic activity, and robustness to harsh environments. Kinetic analysis indicated that Cu/Au/Pt TNPs exhibited strong affinities with H2O2 and 3,3,5,5-tetramethylbenzidine (TMB) as the substrates. To investigate the feasibility of Cu/Au/Pt TNPs-based strategy in biological analysis, H2O2 was chosen as a model analyte and a sensitive and specific detection for H2O2 was acquired with a detection limit of 17 nM. By coupling with glucose oxidase (GOD), this assay could also achieve a sensitive and selective detection of glucose with a detection limit of 33 μM, indicating the versatility of the method. In view of the potential combination with diverse enzyme-related reactions, the Cu/Au/Pt TNPs-based strategy is promising as a universal platform for biosensors.
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Molecular Catalysis
·
2019
·
IF 2.938
Jijin Mai,Yanxiong Fang,Jincheng Liu,Jinhong Zhang,Xiaolan Cai,Yuying Zheng
Partial oxidation of cyclohexane (CHA) to KA oil (cyclohexanone (-one) and cyclohexanol (-ol)) with dry air is one of the most important industrial process. Despite great efforts have made in developing new catalysts, industrial processes are still limited by low conversion and selectivity with harsh condition. Here we report a significantly improved cyclohexane conversion and KA oil selectivity under solar light irradiation by anew photothermal synergistic catalyst, which was prepared by loading Au nanoparticles (Au NPs) onto WO 3 nanosheets (WO 3 NSs) with simple ultrasonic method. A high conversion of 9.0% and a high selectivity of 99.0% are acquired by WO 3 nanosheets-Au nanoparticles (WO 3 -Au) composite under dry air, which are much higher than the simple sum of photocatalysis and thermal catalysis. The significantly improved catalytic properties of cyclohexane oxidation by the WO 3 -Au composite are mainly attributed to the improved light absorption, the effective charge separation and the synergistic effect of photocatalysis and thermal catalysis. The photothermal synergy to improve catalytic activity may be widely used in green industrial catalytic processes.
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JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Renshan Wang,Benxia Li,Yi Xiao,Xueqin Tao,Xintai Su,Xiaoping Dong
Ultrathin semiconductor nanosheets decorated with metallic nanoparticles (NPs) are promising in photocatalysis due to the multi-component interactions. The materials with a series of monometallic Pd and bimetallic Au-Pd NPs anchored on Bi 2 WO 6 ultrathin nanosheets were synthesized and developed as photocatalysts for selective oxidation of aromatic alcohols to aromatic aldehyde. By optimizing the metallic contents, a typical sample of Au(0.25)Pd(0.25)-Bi 2 WO 6 exhibited the highest photocatalytic activity among all the prepared photocatalysts including Au(0.5)-Bi 2 WO 6 , Pd( x )-Bi 2 WO 6 , Au( x )Pd( x )-Bi 2 WO 6 ( x represents the weight percentage of metal in the photocatalyst), along with the improved selectivity for producing benzaldehyde. The extended absorption in visible range, higher efficiency for the transfer and separation of photogenerated charge carriers, and the superior ability for generating active radicals of Au(0.25)Pd(0.25)-Bi 2 WO 6 were demonstrated by DRS spectra, photoelectrochemical measurements, and ESR detection. The effect of the active species for selective oxidation of aromatic alcohols was proved to follow the order of h + + O 2 − > h + >> O 2 − . Accordingly, a possible mechanism based on the interfacial cooperation between bimetallic Au-Pd NPs and Bi 2 WO 6 ultrathin nanosheets was proposed to illustrate the photocatalytic process, where the holes accumulated in Bi 2 WO 6 ultrathin nanosheets and O 2 − produced on metallic NPs synergistically promote the selective oxidation of aromatic alcohols.
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Micro & Nano Letters
·
2018
·Vol. 13
·期 6
·868-871
·
IF 0.841
Yan-meng Li,Li-wei Wang,Ruo-ping Li,Jun-he Han,Ming-ju Huang
Malachite green (C 23 H 25 ClN 2 ) is an illegal fungicide of aquatic products due to its potential carcinogenic, teratogenic, and mutagenic effects. It is typically challenging to detect C 23 H 25 ClN 2 in fish with conventional techniques. The study reported a simple and rapid method for detecting C 23 H 25 ClN 2 on fish surface with surface-enhanced Raman scattering (SERS). Using the seed growth method with trometamol as the modifier, 110 nm in-diameter gold nanoparticles on thin glass as SERS substrate were prepared, which exhibited high SERS activity, reproducibility, stability, and flexibility in SERS measurement. The fish samples required no pretreatment and the entire measurement took <5 min. Quantitative analyses were also conducted. Excellent linear relationships ( R 2 = 0.9397–0.9977) were obtained between the concentrations and the peak intensities of C 23 H 25 ClN 2 at some characteristic peaks with a wide concentrations range (0.5–10 μM). The detection limit can reach 0.5 μM. This method provided an easy and fast way to detect C 23 H 25 ClN 2 on fish surface for food safety.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Ling Wang,Weiwei Meng,Zhangxing He,Wei Meng,Yuehua Li,Lei Dai
A mixed-potential type sensor using a new sensing electrode (SE) of CeVO 4 is developed for NH 3 detection. Well-dispersed Au nanoparticles are introduced into the CeVO 4 -SE by a simple immersion method to further improve the performances, especially the selectivity of the sensor. The sensor using the CeVO 4 -SE exhibits well response-recovery characteristics to NH 3 at 500–600 °C. Good linear correlations between the response potential difference of sensor and the logarithm of NH 3 concentrations are obtained. The sensor displays the negligible cross-sensitivities to CH 4 and CO 2 except NO 2 present in the gas mixture. After the introduction of the Au nanoparticles into the CeVO 4 -SE, the sensitivities of the sensor reach −78.9, −77.3 and −43.1 mV/decade at 500, 550 and 600 °C, respectively, which are much higher than those using the single CeVO 4 -SE. More importantly, the cross-sensitivity of the sensor with CeVO4/Au-SE to NO 2 is almost eliminated. Introduction of 1000 ppm NO 2 in sample gas containing 300 ppm NH 3 causes a response Δ V from 67.2 (for CeVO 4 -SE) to 4.6 mV (for CeVO 4 /Au-SE). The complex-impedance measurements display that introduction of Au can promote electrochemical oxidation reaction of NH 3 to TPBs. The results of the temperature-programmed desorption indicate that the improvement of the selectivity is attributed to the effective depression of NO 2 adsorption in the sensing electrode by introduction of Au.
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Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 7
·1524-1532
·
IF 5.106
Jun-Hao Zhou,Da-Wei Lan,Sheng-Song Yang,Yu Guo,Kun Yuan,Lin-Xiu Dai,Ya-Wen Zhang
Bimetallic hollow structures can be efficiently used to improve the utilization of noble metals in electrocatalysts, but few studies have reported the application of bimetallic hollow nanocomposites for the electrochemical reduction of CO2. Herein, we demonstrated the synthesis of hollow Au–Cu nanoparticles of size ranging from 50 nm to 100 nm with a wall thickness of 4.95 ± 0.81 nm for efficient CO2 reduction reaction (CO2RR) via galvanic replacement and the Kirkendall effect between copper and gold. In the fabrication procedure, a gold precursor was pre-dissolved in TOP to lower the reduction potential of Au3+, which could then be reduced by Cu0. The obtained hollow Au–Cu NPs were then supported on carbon black for CO2RR measurement, and it exhibited a maximum CO FE of 53.3% at −0.7 V (vs. RHE), which was very close to that of Au NP/C, but the gold mass current density of hollow Au–Cu NP/C was much higher. The hollow Au–Cu NP/C also showed good stability in long-time measurements for CO2RR. To find out how the superior catalytic performance was achieved, hollow Au–Cu NP/C was then annealed in O2 and N2. It was found that after being annealed, the catalysts almost totally lost the activity towards CO2RR, which may be due to the partial segregation of Cu species on the nanoparticle surface as well as a decrease in the surface defect density with the improvement in crystallinity. Thus, it was concluded that high dispersion of more Au atoms on the nanoparticle surface together with the presence of more surface defect sites could account for the superior CO2RR performance of the as-synthesized hollow Au–Cu NP/C.
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BIOSENSORS & BIOELECTRONICS
·
2018
·
IF 8.173
Hongying Cheng,Cuiying Hu,Zhongling Ji,Wangcheng Ma,Hongxia Wang
Herein, a doped graphene-like membrane was designed, which was copolymerized to be a solid ionic biosensor by using titania nanotubes (TiNTs), polyaniline (PANI), EvimCl (1-ethyl-3-vinylimidazolium chloride, EVIMC) and chloroauric acid (HAuCl 4 ). The structure of graphene-like arrangement and the copolymerization mechanism of the film were discussed in detail. Because of the high catalytic property , Lactate could be determined on the membrane catalyzed by lactate dehydrogenase (LDH) containing isocitrate dehydrogenase (NAD + ), which was immobilized onto the film by electrostatic attraction . The electrochemical response on the LDH/Au-EVIMC-TiNTs-PANI/ITO was increased by twice than the LDH/TiNTs/PANI/ITO, and exhibited two linear responses within the concentration range from 5.5 × 10 −7 M to 5.55 × 10 −6 M, and 5.55 × 10 −6 M to 3.33 × 10 −3 M, with a detection limit of 1.65 × 10 −7 M ( S / N = 3). The interference study for other common coexistence such as uric acid and hemoglobin revealed that there was no overlapping signal for the detection of Lactate on the biosensor. The developed method proved the most stability in the determination of real blood samples, and the recoveries ranged from 96.7% to 105.8% with a satisfactory result.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Xiao-Lei Zhang,Xue Li,Xiao-Tong Li,Ye Gao,Fang Feng,Gong-Jun Yang
The Au nanoclusters@graphene quantum dots nanocomposite as an electrochemiluminescence (ECL) luminophore was synthesized through amide coupling reaction between Au nanoclusters (Au NCs) and graphene quantum dots (GQDs). The ECL intensity of the as-prepared Au NCs@GQDs was enhanced for 2.6-fold compared with that of Au NCs or 40-fold compared with that of GQDs, which was due to the ECL resonance energy transfer between GQDs as a donor and Au NCs as an acceptor, and excellent electrical conductivity of GQDs. In addition, the synergistic effect likewise improved stability of the ECL signal. A type of “signal-off” solid-state ECL sensor for detection of pentoxifylline was fabricated based on the selective quenching effect of pentoxifylline on the ECL signal of Au NCs@GQDs in alkaline medium. The sensor showed excellent sensitivity and wide linearity for pentoxifylline determination in the range from 7.0 × 10 −7 to 1.2 × 10 -4 mol/L with the detection limit of 9.0 × 10 -8 mol/L (S/N = 3). The proposed method was successfully applied for pentoxifylline detection in pharmaceutical tablet with satisfactory results.
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Journal of Applied Spectroscopy
·
2018
·Vol. 85
·期 1
·160-165
·
IF 0.611
Neng Jing,Wang Xujun,Jia Kan,Sun Peilong
Fe 3 O 4 nanoparticles were first modified with tetraethoxylsilane to form Fe 3 O 4 /SiO 2 nanoparticles, followed by the addition of 3-aminopropyltriethoxysilane and 3-thiolpropyltriethoxysilane to introduce –NH 2 and –SH groups to the surface of Fe 3 O 4 /SiO 2 nanoparticles. Gold nanoparticles were further assembled on the surface of Fe 3 O 4 /SiO 2 via the electrostatic adsorption of –NH 2 and the Au–S bond to produce stable core–shell Fe 3 O 4 /SiO 2 /Au gold/magnetic nanoparticles. These Fe 3 O 4 /SiO 2 /Au gold/magnetic nanoparticles were characterized by a variety of techniques such as transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX), and afterwards conjugated with tetrodotoxin antibodies (Ab) and used as a Raman active substrate (Fe 3 O 4 /SiO 2 /Au–Ab) with Rhodamine B (RhB)-labeled tetrodotoxin antibody as a Raman reporter (Ab–RhB). Upon mixing these reagents with tetrodotoxin (TTX), a sandwich complex [Fe 3 O 4 /SiO 2 /Au–Ab···TTX···Ab–RhB] was generated due to the specific antibody–antigen interactions. The immunocomplex was subsequently separated by an externally applied magnetic source and concentrated into a pellet point, where the laser interrogation of the pellet produced a strong signal characteristic of RhB. The logarithmic intensity of the signal was found to be proportional to the concentration of TTX with a limit of detection of 0.01 μg/mL and a detection linearity range of ~ 0.01–0.5 μg/mL. The established method eliminates the complicated procedures of traditional centrifuging, column separation, and incubation and achieves a rapid detection of tetrodotoxin with improved detection sensitivity.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Jiu-Ju Feng,Zhang-Ying Lv,Su-Fang Qin,Ao-Qi Li,Yao Fei,Ai-Jun Wang
Au porous textile-like sheet arrays (AuPTSAs) have been facilely prepared on a glassy carbon electrode (GCE) by one-step electrodeposition, which are performed at -0.4 V for 600 s in the electrolysis solution containing 10 mM HAuCl 4 , 1.25 M N -methylimdazole and 0.5 M H 2 SO 4 . N -methylimdazole plays an important role in the formation of the gold nanostructures. This approach is simple and facile, whereas no additional issues such as seeds, templates, and surfactants are required. Thus prepared AuPTSAs are perpendicular to the electrode surface and growing in the (1 1 1) directions and their growth mechanism is discussed in some detail. The AuPTSAs show enhanced electrocatalytic activity with better stability toward methanol oxidation in alkaline media, compared with those of polycrystalline Au nanoparticles.
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JOURNAL OF MATERIALS CHEMISTRY
·
2012
·Vol. 22
·期 43
·23169-23174
·
IF 5.968
Xianguang Ding,Yu Zou,Jiang Jiang
The synthesis of hybrid nanostructures has been of great interest to many material scientists, yet simple and facile routes to prepare these structures remain a difficult task with many reaction variables to tune. Herein, we report the synthesis of Au–Cu2S heterodimers from AuCu alloy nanoparticles by simply adding 1-dodecanethiol. Detailed characterization of this structural transformation process revealed that the crucial step of this synthetic approach was the alloy oxidization and subsequent formation of intermediate copper thiolate. Roles of surfactants and sulfur source have also been investigated. These observations provide critical insight into the understanding of the pathways of structure transitions from AuCu alloy to Au–Cu2S heterodimer nanoparticles, and will open up new ways of synthesizing heterodimer nanoparticles from metallic alloys.
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