JOURNAL OF CATALYSIS
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2016
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IF 7.354
Junjie Su,Zhengpai Zhang,Donglong Fu,Da Liu,Xin-Chao Xu,Bianfang Shi,Xu Wang,Rui Si,Zheng Jiang,Jing Xu,Yi-Fan Han
A comparative study of higher alcohols synthesis directly from syngas has been performed over monometallic Co and bimetallic CoCu/SiO 2 catalysts. Particularly, the role of Cu on the origin of active sites and reaction mechanism were investigated thoroughly using multiple techniques such as ex situ X-rays diffraction (XRD), X-ray absorption spectroscopy (XAS) and Raman spectroscopy. Reduction process of CoCu/SiO 2 catalysts was also determined using in situ XRD and in situ Raman spectroscopy while the surface structure of reduced catalysts was detected by CO-DRIFTS. CoCu bimetallic particles covered by Cu atoms are responsible for alcohols synthesis. The intrinsic kinetics was performed over both catalysts under realistic reaction conditions. By comparing the kinetic parameters, including apparent activation energies and reaction orders, the promotional effects of Cu have been identified as: (1) weakening the CO/HCO dissociation and reducing the formation of CH x species; (2) controlling surface Co ensemble size and inhibiting CH x insertion.
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MATERIALS & DESIGN
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2016
·
IF 3.997
Tianqi Hu,Hongtao Chen,Mingyu Li
This paper presents a novel die attach material that withstands high working temperatures of up to 676 °C after < 40 min of reflow at 250 °C. The die attach material was preform compressed with Cu@Sn core-shell structured microparticles . When the reflow temperature reached 232 °C, the outer Sn layer melted and connected the inner Cu cores. After reflow soldering at 250 °C for 8 min, the outer Sn completely transformed into network-like Cu-Sn intermetallic compounds (IMCs), which have a higher remelting temperature than Sn (415 °C for Cu 6 Sn 5 and 676 °C for Cu 3 Sn). Consequently, the inner Cu cores were interconnected by the formed network-like Cu-Sn IMCs with a high remelting temperature of at least 415 °C. If the sample was reflowed at 250 °C for 40 min, the outer Cu 6 Sn 5 layer completely transformed into Cu 3 Sn, and the resulting bondline could sustain a higher temperature. The shear strengths of the resulting bondlines after reflow soldering at 250 °C for 8 and 40 min were 29.35 and 18.78 MPa at 400 and 500 °C, respectively.
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Polymer Chemistry
·
2016
·Vol. 7
·期 25
·4226-4236
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IF 5.687
Wenchao Ma,Dong Chen,Yuhong Ma,Li Wang,Changwen Zhao,Wantai Yang
With ethyl-α-bromophenylacetate (EBPA) as an initiator and Cu(dap)2Cl (dap = 2,9-bis(p-anisyl)-1,10-phenanthroline) as a photoredox catalyst, controlled radical polymerizations of poly(ethylene glycol)methyl ether methacrylate (PEGMA) and methyl methacrylate (MMA) are demonstrated under LED light lamp irradiation (4500 μW cm−2@420 nm). The catalysis cycles proceed in the presence of N,N-dimethylaniline (DMA) or tris[2-(dimethylamino)ethyl]amine (Me6TREN), which could serve as reductants to regenerate a Cu(I) complex from the oxidized Cu(II) complex. In addition, Me6TREN plays another important role as an efficient ligand for the copper-based photopolymerization of methacrylate monomers. Good linear evolution of molecular weight (Mn) with monomer conversion is observed under the optimized conditions. Specifically, with [PEGMA] : [EBPA] : [Cu(dap)2Cl] : [Me6TREN] = 31 : 1 : 0.015 : (0.15–0.45), poly(PEGMA) (PPEGMA) with polydispersity indexes (PDI) as low as 1.15 are obtained. To further verify the living nature of this system, block copolymers of PPEGMA-b-PMMA with high molecular weights and narrow molecular weight distributions (Mn,GPC = 59 200 g mol−1, PDI = 1.28 and Mn,GPC = 93 700 g mol−1, PDI = 1.44, respectively) are prepared using PPEGMA-Br (Mn,GPC = 11 600 g mol−1; PDI = 1.13) as a macroinitiator. The polymers produced with Cu(dap)2Cl/Me6TREN as a catalyst and the PMMA obtained with Cu(dap)2Cl/DMA as a catalyst are colorless which is different from the heterogeneously catalyzed ATRP for its notorious Cu metal residue.
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Nanoscale Research Letters
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2017
·Vol. 12
·期 1
·1-8
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IF 2.833
Zhang Jingyi,Feng Anni,Bai Jie,Tan Zhibing,Shao Wenyao,Yang Yang,Hong Wenjing,Xiao Zongyuan
The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu (F) /RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu (F) /RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.
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CHEMICAL ENGINEERING JOURNAL
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2017
·
IF 6.216
Xiaoyuan Zhang,Ping Gu,Xiaoyuan Li,Guanghui Zhang
Nano Cu 2 O/Cu modified activated carbon composite (nano Cu 2 O/Cu-C) was firstly synthesized by a simple and efficient hydrothermal method and used to adsorb iodide ion (I − ) from simulated radioactive wastewater . Nano Cu 2 O/Cu loaded and uniformly distributed on activated carbon with a diameter of 80–100 nm. The composite exhibited excellent adsorption performance, which was primarily attributable to the synergistic effect of nano Cu 2 O/Cu and activated carbon. Langmuir isotherm and pseudo-second-order kinetic model accurately represented the experimental data of I − adsorption. On the basis of the Langmuir isotherm, the maximum adsorption capacity of I − by nano Cu 2 O/Cu-C was 41.2 mg/g, which is significantly higher than pure nano Cu 2 O and activated carbon. The adsorption was affected only slightly by pH and other interfering ions. Additionally, X-ray photoelectron spectroscopy was used to elucidate the possible adsorption mechanism. This study provides new insight into the fabrication and practical application of high-performance adsorbent in removing radioactive I − from wastewater.
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Nano Energy
·
2016
·
IF 11.553
Yurui Xue,Yuan Guo,Yuanping Yi,Yongjun Li,Huibiao Liu,Dan Li,Wensheng Yang,Yuliang Li
Here we show that a high efficient hydrogen evolution reaction which was carried out on the in-situ growth of self-supported core-shell nanowires array consisting of graphdiyne as the shell and Cu as the core on Cu foams (Cu@GD NA/CF). Subject to potential cycling treatment in 0.5 M H 2 SO 4 , the Cu@GD NA/CF exhibits highly catalytic activity for hydrogen evolution reaction with an onset overpotential of 52 mV and a Tafel slope of 69 mV dec −1 . Our findings suggest that synergetic interaction between GD and Cu is crucial for the catalytic performance of the electrode. This electrode needs only overpotentials of 79 and 162 mV to achieve catalytic current densities of 10 and 100 mA cm –2 , respectively, and maintains its catalytic activity for almost 20 h. The attractive performances of such array make it promising candidate as a future high-performance catalyst for applications. Summary The first GD based 3D carbon nanoarchitectures with well-defined porous network structures working as a highly active hydrogen evolution cathode is developed. Its excellent electrocatalytic activities , combined with low-cost, convenient and scale-up preparation process, make it promising candidate for practical and efficient energy applications .
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CHINESE CHEMICAL LETTERS
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2016
·
IF 1.947
Yang Chang,Chen Shen,Pin-Yi Li,Lei Fang,Zai-Zai Tong,Min Min,Chun-Hua Xiong
Polyacrylonitrile beads (PAN) cysteine (CS) was synthesized from polyacrylonitrile beads (PAN) and cysteine (CS). The content of the functional group and the percentage conversion of the functional group of PAN-CS prepared under the optimum condition using response surface methodology (RSM) for the first attempt were 3.22 mmol/g and 35.78%. The structure was characterized by FT-IR and elemental analysis . The adsorption properties of the resin for Cu(II) were investigated by batch and column experiments. Batch adsorption results suggested that PAN-CS had higher adsorption capability for Cu(II) than other metal ions and maximum saturated adsorption capacity was 184.7 mg/g. The resin and its metal complexes were studied by FT-IR. Furthermore, the resin can be eluted easily using 1 mol/L HCl. PAN-CS can provide a potential application for selective removal of copper from waste solution.
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JOURNAL OF HAZARDOUS MATERIALS
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2017
·
IF 6.065
Yong Feng,Po-Heng Lee,Deli Wu,Zhengyuan Zhou,Hangkong Li,Kaimin Shih
Copper ions (Cu 2+ and Cu + ) have shown potential as Fenton-like activators for the circumneutral removal of organic contaminants from aqueous solutions. However, the major active species (cupryl species (Cu 3+ ) versus hydroxyl radical ( OH)) produced during the activation of hydrogen peroxide by Cu + remain unclear. In this study, Cu + -O 2 oxidation, in which hydrogen peroxide is produced via the activated decomposition of dissolved molecular oxygen, was used to degrade sulfadiazine, methylene blue, and benzoic acid. The results showed that both sulfadiazine and methylene blue could be efficiently degraded by Cu + -O 2 oxidation in a wide effective pH range from 2.0 to 10.0. Quenching experiments with different alcohols and the effect of Br − suggested that Cu 3+ rather than OH was the major active species. Electron paramagnetic resonance detected 5,5-dimethyl-2-hydroxypyrrolidine-N-oxyl (DMPO-OH), which was probably produced by the oxidation of DMPO by Cu 3+ or OH formed as a product of Cu 3+ decomposition. 4-hydroxybenzoic acid was produced during the degradation of benzoic acid by Cu 3+ . The findings of this study may help to explain the inconsistency regarding the dominant active species produced by the interaction of Cu + and hydrogen peroxide.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2017
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IF 4.233
Shi Mo,Hong Qun Luo,Nian Bing Li
Green corrosion inhibitors are of great benefit to the protection of pipes or tanks in seawater systems. The properties of the corrosion inhibitor such as toxicity and anticorrosion performance are closely related to its molecular structure. Some thiazole derivatives are commonly known as food flavors . The influences of two thiazole flavor ingredients on Cu corrosion in NaCl solution were analyzed in this study, namely, 4-methyl-5-vinylthiazole (MVT) and 5-(2-hydroxyethyl)-4-methylthiazole (HMT). Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were employed to evaluate their anti-corrosion abilities. Theoretical calculations were conducted to investigate their possible adsorption modes. The thiazole ring endows the two compounds with the high inhibition performace. However, with a conjugated system , the ethenyl has a more pronounced contribution to electron donation and adsorption ability on the Cu surface than hydroxyethyl group.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2017
·
IF 3.133
Feng Zheng,Hanqin Gong,Zheng Li,Weiguang Yang,Jiahe Xu,Pengfei Hu,Yang Li,Yu Gong,Qiang Zhen
WO 3 microspheres film with a tertiary, textured and porous structure assembled of WO 3 hierarchical nanorods has been directly prepared on Cu foil using a one-step hydrothermal method . The field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectrum, X-Ray Diffraction (XRD), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) are used to reveal the surface microtopography, crystal structure, elementary composition, valence state and formation mechanism of WO 3 tertiary structure. Moreover, the electrochemical properties and supercapacitive performances of WO 3 microspheres film are also intensively investigated. The WO 3 microspheres film has high specific capacitances of 485, 426, 372, 319 and 260 F g −1 at unit currents of 0.5, 1, 2, 5 and 10 A g −1 and exhibits good cycle stability (93% after 5000 cycles) and reversibility (98.5%), a lower charge transfer resistance (0.5 Ω) and high energy densities ranging from 21 to 17 W h kg −1 corresponded to high power densities varied from 150 to 3000 W kg −1 .
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 7
·2031-2038
·
IF 4.58
Shao Fengying,Jiao Lei,Wei Qin,Li He
The interference by dissolved oxygen is an obstacle in electrochemical immunoassays. The authors are reporting here on a method that employs a working potential that is below the reduction potential for oxygen and hence is not interfered by oxygen/air. Ternary Pt-Co-Cu nanodendrites were prepared by a one-pot reaction. They were placed on a glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs) where they showed excellent catalytic activity toward the reduction of hydrogen peroxide at a reduction potential of −0.015 V (vs. SCE). Dissolved oxygen, in contrast, is not reduced at this potential. In order to obtain a sandwich-type of voltammetric immunosensor, antibody against insulin (Ab 1 ) immobilized on the AuNPs on the GCE. The secondary antibody (Ab 2 ) was labeled with Pt-Co-Cu nanodendrites as signal marker for signal amplification. After adding hydrogen peroxide, its catalytic oxidation by the immunosensor depends on its loading with insulin. Hence, insulin can be quantified due to the positive correlation that exists between current and the concentration of ternary Pt-Co-Cu nanodendrites on the electrode. The sensor has a linear response in the 0.2 pM to 2 nM insulin concentration range, with a 0.08 pM detection limit. The assay is well reproducible, acceptably selective, and the sensor is fairly stable over time.
One-pot synthesis of ternary Pt-Co-Cu nanodendrites for oxygen interference-free electrochemical detection of insulin. GCE (glassy carbon electrode). Pt-Co-Cu NP (Pt-Co-Cu nanoparticles). BSA (bovine serum albumin). Ab 1 (coating antibody). Ab 2 (labeling antibody). The sandwich-type electrochemical immunosensor has been used for detecting insulin with high sensitivity, which is based on Au nanoparticles for biomolecular immobilization and the one-pot synthesis of ternary Pt-Co-Cu nanodendrites as label enhancer.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yingying Xu,Mengyao Li,Yingjiu Zhang,Hongzhang Song,Haoshan Hao
A series of Bi 2 Sr 2 Co 2 O y (BSCO), Bi 2 (Sr 2/3 Ba 2/3 Ca 2/3 )Co 2 O y (BSBCCO), Bi 1.9 Cu 0.1 (Sr 2/3 Ba 2/3 Ca 2/3 )Co 2 O y (BCSBCCO) and Bi 1.8 Ag 0.2 (Sr 2/3 Ba 2/3 Ca 2/3 )Co 2 O y (BASBCCO) ceramic samples were prepared to optimize the thermoelectric properties of BSCO by high entropy doping combined with Cu/Ag doping. High entropy doping improves the carrier mobility significantly, due to a sintering effect in liquid phase and an additional conduction path. Cu/Ag acceptor doping increases the carrier concentration and Seebeck coefficients. Both them enhance the electrical transport performance of doped samples effectively. Specially, the random distribution of several different cations caused by high entropy doping and Cu/Ag doping can enhance the phonon scattering, which greatly reduces the thermal conductivity of doped samples. Finally, the thermoelectric figure of merit ( ZT ) value of the BASBCCO sample is improved to 0.36 at 923 K on the basis of high entropy doped BSBCCO ( ZT = 0.28 at 923 K), which is twice that of the pristine sample.
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