CATALYSIS LETTERS
·
2019
·Vol. 149
·期 2
·361-372
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IF 2.372
Liu Yanan,Yang Zhao,Zhang Xinyi,He Yufei,Feng Junting,Li Dianqing
Abstract A series of CeO 2 with the morphology of nanocube (NC), nanopolyhedron (NP) and nanorod (NR) were synthesized by hydrothermal method as substrates to support monometallic Au catalysts. Insight into support morphology-dependent the property of active component and catalytic behavior for the selective hydrogenation of phenylacetylene has been performed. Specifically, nanocube ceria could disperse monometallic Au nanoparticles due to a large amount of low coordinated sites that readily generated the strong interaction for anchoring active metal, whereas the polyhedron and rod-like ceria supported Au nanoparticles possessed large size and wide particle distribution. As expected, well-dispersed and stable Au/CeO 2 nanocube demonstrated 83% of selectivity towards styrene when the conversion of phenylacetylene reached 90%, which was much higher than that of others. Preferable activity was mainly ascribed to small size of Au nanoparticles, which facilitated the adsorption/dissociation of hydrogen considered as the rate-determining step. Enhanced selectivity was due to the electronic effect that caused by strong interaction between Au and cubic CeO 2 , which also contributed to good stability. This work not only provides a facile method for the preparation of highly dispersed and efficient Au/CeO 2 catalysts by modulating the morphology of support, but also offers a novel idea for the fabrication of other highly dispersed supported metal catalysts with enhanced behavior in heterogeneous catalysis. Graphical Abstract
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CHEMISTRY-A EUROPEAN JOURNAL
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2019
·Vol. 25
·期 23
·5904-5911
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IF 5.16
Guoqiang Liu,Zhiqing Cui,Miaomiao Han,Shengbo Zhang,Cuijiao Zhao,Chun Chen,Guozhong Wang,Haimin Zhang
Graphical Room at the active site : A room-temperature redox approach is used to prepare a composite core–shell-structured Au@CeO 2 electrocatalyst (see figure) composed of small gold nanoparticles (<10 nm) and rich oxygen vacancies in CeO 2 nanoparticles to synergistically boost the electrocatalytic activity toward the N 2 reduction reaction (NRR) to NH 3 . Electrosynthesis of NH 3 through the N 2 reduction reaction (NRR) under ambient conditions is regarded as promising technology to replace the industrial energy- and capital-intensive Haber–Bosch process. Herein, a room-temperature spontaneous redox approach to fabricate a core–shell-structured Au@CeO 2 composite, with Au nanoparticle sizes below about 10 nm and a loading amount of 3.6 wt %, is reported for the NRR. The results demonstrate that as-synthesized Au@CeO 2 possesses a surface area of 40.7 m 2 g −1 and a porous structure. As an electrocatalyst, it exhibits high NRR activity, with an NH 3 yield rate of 28.2 μg h −1 cm −2 (10.6 μg h −1 mg −1 cat. , 293.8 μg h −1 mg −1 Au ) and a faradaic efficiency of 9.50 % at −0.4 V versus a reversible hydrogen electrode in 0.01 m H 2 SO 4 electrolyte. The characterization results reveal the presence of rich oxygen vacancies in the CeO 2 nanoparticle shell of Au@CeO 2 ; these are favorable for N 2 adsorption and activation for the NRR. This has been further verified by theoretical calculations. The abundant oxygen vacancies in the CeO 2 nanoparticle shell, combined with the Au nanoparticle core of Au@CeO 2 , are electrocatalytically active sites for the NRR, and thus, synergistically enhance the conversion of N 2 into NH 3 .
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Frontiers in Chemistry
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2019
·
IF 3.782
Zhang Ying,Qu Rongjun,Xu Ting,Zhang Yu,Sun Changmei,Ji Chunnuan,Wang Ying
To further increase the quantity and density of functional groups on adsorbent, terminal triethylenetetramine hyperbranched dendrimer-like polymer modified silica-gel (SG-TETA and SG-TETA2) was synthesized. The hyperbranched dendrimer-like polymer was successfully introduced onto silica gel and new cavities were formed, which was demonstrated by FTIR, SEM, and BET. The highest adsorption capacities of SG-TETA and SG-TETA2 obtained from Langmuir model toward Au(III) were 2.11, and 2.27 mmol g−1, respectively, indicating that SG-TETA2 possessing more functional groups had a better adsorption ability. Moreover, the adsorbents combined with Au(III) ion through chelation and electrostatic attraction mechanism, after which reduction reactions for Au(III) ion loaded on adsorbents proceeded. SG-TETA2 had better adsorption selectivity than SG-TETA in removing Au(III) in Au-existed ion solution systems. SG-TETA2 had higher overall adsorption capacities compared to silica-gel-based hyperbranched polymers functionalized by diethylenetriamine. Therefore, the effective recovery makes SG-TETA2 a practical adsorbent in removing Au(III) ion from e-wastes and industrial effluents with much prospect.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Fen-Ying Kong,Lei Yao,Rong-Fang Li,Heng-Ye Li,Zhong-Xia Wang,Wei-Xin Lv,Wei Wang
Nitrogen-doped reduced graphene oxide loading with Au-Ag bimetallic nanoparticles (NG-Au-Ag) was synthesized by a facile two-step strategy. The successful formation of NG-Au-Ag nanocomposites were confirmed by transmission electron microscopy (TEM), Raman spectroscopy , X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. Furthermore, NG-Au-Ag nanocomposites were modified onto the electrode surface for the voltammetric detection of daunorubicin (DNR). The results showed that the NG-Au-Ag modified electrode expressed high electrocatalytic activity toward the redox of DNR, allowed detection of DNR with wide linear range (0.01 μg mL −1 to 15 μg mL −1 ) and low detection limit (3 ng mL −1 ). The modified electrode also exhibited satisfactory performance for the detection of DNR in human serum samples.
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JOURNAL OF MEMBRANE SCIENCE
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2019
·
IF 7.015
Zhijie Zhang,Yan Yang,Congling Li,Rui Liu
Effective separation of oil/water emulsion and removal of organic dyes are of critical importance for environmental protection. In this study, superhydrophobic polyacrylonitrile (PAN) nanofibrous membrane embedded Au nanoparticles (NPs) in cavity has been prepared through a facile electrospinning and subsequent surface-modification strategy. The as-prepared Au@ZIF-8@PAN-TD membrane exhibited a water contact angle (WCA: ∼155.5°), an oil contact angle in air (OCA: ∼0°) and a WCA under-oil (∼158°). The composite membrane has demonstrated its ability to achieve efficient water/oil separation and in situ catalytic degradation of organic dye (e.g. 4-nitrophenol). The superhydrophobic Au@ZIF-8@PAN-TD membrane with a hierarchical porous structure would open an avenue for the purification of polluted oily water system.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Chen Wang,Guo Lin,Jiling Zhao,Shixing Wang,Libo Zhang,Yunhao Xi,Xiteng Li,Ying Ying
A novel adsorbent (UiO-66-TA) was presented by modifying metal-organic framework composites with thioctic acid. UiO-66-TA were characterized by fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), thermogravimetric (TG), Brunner-Emment-Teller (BET) measurement and X-ray photoelectron spectroscopy (XPS), which indicating that it had excellent morphology and specific surface area. The adsorption performances of UiO-66-TA for Au(III) were studied. The results showed that UiO-66-TA had a strong adsorption capacity under acidic conditions and the optimal pH was 2.0. Isotherm and kinetic adsorption were also conducted and found that the experimental values correspond to Langmuir model and pseudo-second-order isotherm model, indicating that the mechanism is mainly chemical adsorption on a uniform surface. Wastewater experiment showed that UiO-66-TA can be used for highly selective recovery Au(III) in actual life. The regeneration and thermodynamic experiments indicated that UiO-66-TA can be reused and were a spontaneous endothermic process. XPS analysis and the zeta potential proved that the main adsorption mechanisms were ion exchange and chelation. DFT calculation found that there are two ways to combine Au with S on UiO-66-TA and their distances are 2.38 Å and 2.39 Å, indicating that the gold and sulfur play a major role in chelation. In summary, UiO-66-TA was a hopeful adsorbent and could be used to collect gold ions from wastewater in a sustainability perspective.
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OPTICS EXPRESS
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2019
·Vol. 27
·期 17
·23981-23995
·
IF 3.561
Anxin Jiao,Hua Zhang,Linlin Xu,Yue Tian,Xiangdong Liu,Ming Chen,Feng Chen
The blue laser beam-excited surface-enhanced Raman scattering (SERS)-based pH sensing holds great promise for avoiding undesired thermal heating effect on some special temperature-vulnerable molecules, as compared to the vast majority studies by exciting in the red or near-infrared (NIR). Herein, we report an ingenious approach to support core-shell Au@Ag nanodendrites (NDs) on TiO2 nanowires, which can possess enhanced SERS activity under 473 nm laser excitation, owing to the improved charge-transfer effect on modified TiO2 support by inserting plasmonic Au@Ag. By using pH-indicating 4-mercaptobenzoic acid (4-MBA), the obtained TiO2/Au@Ag NDs can not only exhibit high sensitive linear-responses of pH changes ranging from pH 4.0 to 9.0 in different solutions (deionized water, NaCl, CaCl2, and MgCl2) but also provide excellent temperature stability under 4°C, 25°C and 37°C temperatures as well as good time stability after storage for 10 days. The established SERS-pH sensing by using shorter wavelength laser excitation is highly desirable for understanding physiological process in temperature-vulnerable microenvironment.
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NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 20
·7613-7619
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IF 3.069
Yuanjie Teng,Yuchao Zhang,Zeyu Ren,Zhenni Wang,Wenhan Liu,Kang Shao,Zaifa Pan
In this work, a facile surface-enhanced Raman scattering (SERS) substrate formed on a water/oil interface was prepared by adding n-hexane to Au colloids through simple vortex mixing without the involvement of any organic additives. In this process, the background SERS signal was reduced, which is good for the detection of adsorbed analyte molecules on the interfacial substrate. Furthermore, an Au monolayer nanofilm (Au MLF) spontaneously formed at the water/n-hexane interface after just a few seconds of simple vortex mixing, which is much shorter than the time required for self-assembly of nanoparticle films using organic additives. Transmission electron microscopy characterization results showed that the Au nanoparticles are close-packed and that the density of the Au nanoparticles on the interface could be controlled by varying the vortex mixing time and volume of n-hexane. The enhanced Raman signal was mainly as a result of the localized surface plasmon resonance and adsorption enrichment effects. The substrate showed good repeatability, with an relative standard deviation (RSD) of 5.02% (n = 6 × 8) by random selection and an RSD of 5.5% for an area of 4.0 μm × 4.0 μm. Finally, the proposed substrate was successfully applied in the detection of rhodamine B (RhB), malachite green (MG) and ciprofloxacin (CIP), with enhancement factors of 1.1 × 106 (RhB), 0.8 × 106 (MG), and 2.7 × 106 (CIP).
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Yuqi Geng,Jiaqi Li,Wenjuan Lu,Ning Wang,Zeyang Xiang,Yanzhao Yang
In this paper, superparamagnetic Fe 3 O 4 @SiO 2 -NH 2 nanoparticles were applied to adsorb Au(III)/Pd(II)/Pt(IV) in HCl medium. The successful synthesis of Fe 3 O 4 @SiO 2 -NH 2 was characterized through TEM, SEM and FT-IR. Electrostatic interaction between magnetic NPs and metal anions was proposed as the main adsorption mechanism by zeta potential analysis. Maximum adsorption capacities and adsorption behaviors under metal anions concentrations, acidity, NaCl, kinetic and isotherm models were investigated. Notably, the Fe 3 O 4 @SiO 2 -NH 2 shows the excellent acidity and salinity resistance on Au(III), Pd(II) adsorption. The separation routine among Au(III), Pd(II) and Pt(IV) was proposed. As investigated, Pt(IV) could be isolated due to the less adsorption amount onto Fe 3 O 4 @SiO 2 -NH 2 (≤1%). Then, the adsorbed Au(III) was eluted selectively by HCl + N-hexanol alcohol + ethanol + H 2 O 2 mixing solution. Then, the adsorbed Pd(II) was completely eluted by thiourea solution. The recovery efficiencies of Au(III), Pd(II) and Pt(IV) were kept over 92%, 97% and 94% respectively, during 5 turns of cycling separation experiments. Total loss amount of Fe is around 7%. Hence that, the particle demonstrates the good stability and high adsorption capacity, which possess great potential for practical Au(III), Pd(II) and Pt(IV) separation.
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SENSORS
·
2018
·Vol. 18
·期 6
·1946
·
IF 2.475
Bing Liu,Min Li,Yaoshuai Zhao,Mingfei Pan,Ying Gu,Wei Sheng,Guozhen Fang,Shuo Wang
In this work, a sensitive electrochemical immunosensor has been reported for the determination of norfloxacin in animal-derived foods. The poly (amidoamine) dendrimer encapsulated gold nanoparticles (PAMAM-Au) played dual roles in the proposed sensing platform which not only accelerated the electron transfer process of sensing, but also increased the efficiency of the immobilized antibody. The HRP-labeled antigen, as the signal labels in the immunosensor, was introduced to catalyze the following reaction of the substrate hydroquinone with the aid of H2O2in the competitive reaction. On the basis of the signal amplification of PAMAM-Au, the signal intensity was linearly related to the concentration of norfloxacin in the range of 1 μg·L−1–10 mg·L−1. All the results showed that the proposed strategy with low LOD (0.3837 μg·L−1) and favorable recovery (91.6–106.1%) in the practical sample, and it could provide a suitable protocol for norfloxacin detection in animal-derived foods with high sensitivity, good accuracy, and stability.Keywords:electrochemical immunosensor;dendrimer;signal amplification;norfloxacin;animal-derived foods
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Journal of Cleaner Production
·
2018
·
IF 5.651
Guo Lin,Shixing Wang,Libo Zhang,Tu Hu,Jinhui Peng,Song Cheng,Likang Fu,C. Srinivasakannan
A bioadsorbent was synthesized by modifying corn bract with 2-aminothiazole for the selective recovery of gold. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the bioadsorbent with the aim of understanding the mechanism of adsorption. Adsorption isotherms and kinetics data were determined and modeled. The adsorption capacity of Au(III) was 1668 mg/g, much higher than the values reported in the literature due to the ion exchange and chelation between the amino/thiol groups and Au(III). Additionally, the effect of pH and other ions on the Au(III) adsorption capacity were assessed. The adsorption isotherm was found to be consistent with the Langmuir isotherm model, and the kinetic was consistent with the pseudo-second-order kinetic model . Further regeneration and cyclic adsorption tests were performed to ensure the effectiveness of the bioadsorbent in commercial applications.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Li Li,Tianyi Zhang,Jianhua Lü,Changli Lü
Carbon dots (CDs), the youngest member in the carbon nanomaterial family, have drawn considerable attention due to their interesting optical, physicochemical and electronic properties as well as broad promising applications. Here, we developed a facile and effective strategy for the preparation of Au nanoparticles stabilized by thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) functionalized carbon dots (Au@CD@P) under the gentle water media. The as-designed dopamine(DA)-terminated PNIPAM can be easily anchored to CDs via mussel-inspired chemistry route. Both CD@P and CDs could well stabilize the Au nanoparticles with interesting assembled structure. The as-prepared Au@CD and Au@CD@P nanohybrids with good dispersibility and stability exhibited the intriguing catalytic activity for reduction of p -nitrophenol ( p -NP). Especially, Au@CD@P as catalyst also played a switching role in regulating the catalytic rate by temperature. In addition, Au@CD@P exhibited excellent recyclability which may have potential in green chemical industry for developing high-activity catalysts and easy production methods.
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