JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
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2019
·Vol. 28
·期 8
·5165-5171
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IF 1.476
Zhang Xin,Wan Dongqin,Peng Kun,Zhang Wei
Copper matrix composites reinforced with reduced graphene oxide (rGO) were fabricated via charge adsorption process, thermal reduction, and hot-press sintering process. We investigated the effect of rGO on the thermal conductivity, electrical conductivity, mechanical properties, and microstructure of the composites. By controlling the reaction process, copper on the rGO surface was oxidized to form Cu 2 O. The presence of Cu 2 O at the interface enhanced interfacial bonding strength and reduced the interfacial thermal resistance, thus improving the thermal conductivity and mechanical properties. This enhancement occurred at low rGO contents. By contrast, excessive amounts led to rGO agglomeration and a degradation of the performance. At the optimum rGO content of 0.6 wt.%, the composites had a 10% increase in thermal conductivity and a 46% increase in yield strength ( σ 0.2 ), while maintaining high electrical conductivity.
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Molecular Catalysis
·
2019
·
IF 2.938
Xin Li,Haixing Wang,Peiyong Sun,Shenghong Zhang,Zhilong Yao
Cu/ZrO 2 catalysts with or without boron modification were prepared, characterized, and evaluated in the hydrogenation of sec -butyl acetate (SBA) to 2-butanol. Cu/ZrO 2 catalysts were active for the hydrogenation of SBA but suffered serious deactivation due to the leaching of Cu. Introduction of boron onto Cu/ZrO 2 catalysts improved the dispersion of Cu species, the surface Cu + /Cu 0 ratios, and the catalyst stability owing to the enhanced interaction between Cu species and support. However, it decreased the intrinsic activity of Cu towards the hydrogenation of SBA and complicated the reaction network by accelerating acid-catalyzed isomerization and transesterification processes as a result of the strengthened acidity by boron. A further kinetic analysis unravelled that the reaction orders for SBA and H 2 are 0.58 and 0.83, respectively, and the apparent activation energy is 47 kJ/mol. Such understanding of the structural evolution of CuB/ZrO 2 catalysts and the consequent catalytic performances with the B contents may provide insights useful for the design of Cu catalysts with desirable stability for hydrogenation of SBA and other esters.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Lu Fan,Yingxi Wang,Ling Li,Jianggang Zhou
In this study, 2-amino-terephthalic acid was designed for construction of MOFs , and carbon quantum dots (CQDs) were designed to activate the Metal Organic Frameworks (MOFs) to be used as fluorescent sensor for selectively detection for Fe 3+ and Cu 2+ , enhancing the fluorescence to an “on” state by the hybrid with CQDs in the MOFs as activating agent; quenching the fluorescence to an “off” state by removal of CQDs through the metal competitive coordination substitution strategy. Using this strategy, the prepared CQDs/MOFs material can be used as a fluorescence “on-off” probe for highly sensitive detection of Fe 3+ and Cu 2+ in aqueous solution. It was found that the LOD of CQDs/MOFs for sensing Fe 3+ and Cu 2+ were 2.3 ppb and 1.3 ppb, respectively. It was proved that the CQDs/MOFs has little cytotoxicity to 4T-1 cells, indicating the potential application in the detection for Fe 3+ and Cu 2+ ions in cells.
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Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 48
·15285-15291
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IF 6.641
Mingrui Liu,Lijin Wang,Zhongyuan Guan,Zhenyang Liu,Yongsheng Zhu,Aiwei Tang
The optical properties of doped semiconductor nanocrystals (NCs) are strongly affected by the dopant position inside the host lattice. However, controlling the dopant position in Cu(I) doped core/shell semiconductor NCs is still unexplored due to the high ionic mobility of Cu(I) ions at the doping temperature. In this paper, we report the doping of Cu(I) ions into CdS/ZnS core/shell NCs via a cation exchange strategy. During the doping, the exciton emission of CdS NCs is reduced and the dopant emission becomes intensified as the doping level is increased from 0 to 1.1%, and the PL profile of the final product is very similar to that of uncoated CdS:Cu(I) NCs. Such an optical change is very different from that observed in the products synthesized by a conventional method, in which no exciton emission of CdS NCs is observed. During the Cu(I) doping process, the variation of the dopant emission may arise from the doping position change from the outside ZnS shell to the inside CdS core in the CdS/ZnS core/shell NCs. The deduction can be further verified by the optical change by direct heating of a small amount of Cu(I) doped CdS/ZnS NCs in a non-coordinating solvent. This work offers a cation exchange strategy for fabricating Cu(I) doped core/shell NCs with tuned dopant positions, which will open up rich opportunities for tuning the optoelectronic properties of Cu(I) doped semiconductor NCs.
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JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Tiecheng Wang,Liling Zhou,Yang Cao,Ying Zhang,Guangzhou Qu,Xuetao Guo,Hanzhong Jia,Lingyan Zhu
Heavy metals and natural organic matters (NOM) form very stable heavy metal-NOM complexes in aqueous, facilitating the migration of heavy metals and enhancing their potential risks. In this study, non-thermal plasma oxidation was attempted to destroy the heavy metal-NOM complexes, with Cu-humate (Cu-HA) as a model. The decomplexation efficiency reached 86.1 % within 50 min of plasma oxidation at 16 kV. The generated reactive species by the non-thermal plasma, including O 2 − , 1 O 2 , OH, attacked the carboxyl and hydroxyl functional groups of HA, leading to cleavage of the Cu-O bonds, decomplexation of Cu-HA, and release of free Cu(II). Meanwhile, a variety of small molecular intermediates, including phenols, benzoic acids, esters, amines, ketones, acetic acid, formic acid, and oxalic acid, were generated due to attack by the oxidative species on the aromatic moiety and double bonds in Cu-HA. As a consequence of decomplexation, the residual toxicity of Cu-HA to Scenedesmus obliquus was distinctly reduced. This study provides a potential technique to decomplex heavy metal-NOM complexes, and reduces their toxicity to typical Scenedesmus obliquus.
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PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 26
·14982-14989
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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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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Xin Xu,Kang Shen,Min Wen,Qingliu Wu,Guangya Hou,Huazhen Cao,Liankui Wu,Guoqu Zheng,Yiping Tang
A three-dimensional (3D) Cu/Fe 3 O 4 anode material was synthesized successfully via a simple and flexible route. Cu nanowires grew on Cu sheet directly by oxidation and reduction as 3D current collector, Fe 3 O 4 nanosheets were coated on the collector surface by electrodeposition to form 3D Cu/Fe 3 O 4 nanocomposite. The characterization results showed that oxidation time affects the morphology of Cu nanowires greatly, the collector has optimum 3D nanostructure at 200 s oxidation with high performance. The 3D Cu/Fe 3 O 4 anode possessed high cycling capability, the capacity reached 700 mAh/g after 300 cycles at 0.5 A/g. And it exhibited high rate performance, the capacity reached 482 mAh/g at 2 A/g and it recovered to 853.5 mAh/g at 0.2 A/g after 100 cycles of different rate tests. The high performance is ascribed to the unique 3D nanostructure of current collector, which provides sufficient space for large volume change and stress release, and reduces the distance for transporting lithium ions and electrons.
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GREEN CHEMISTRY
·
2019
·Vol. 21
·期 3
·606-613
·
IF 9.405
Zhenbing Xie,Bingfeng Chen,Haoran Wu,Mingyang Liu,Huizhen Liu,Jianling Zhang,Guanying Yang,Buxing Han
Transformation of biomass or biomass-based feedstocks into fuels or valuable chemicals is of great importance for the sustainable development of our society. Mesoporous Al2O3–ZrO2 with different Al : Zr molar ratios was prepared by the sol–gel method, and Cu–Ni/Al2O3–ZrO2 catalysts were fabricated by the impregnation method. The catalytic performances of the bifunctional catalysts were studied in the selective hydrogenation of levulinic acid (LA) into 2-methyltetrahydrofuran (MTHF). It was demonstrated that both Cu : Ni and Al : Zr ratios affected the selectivity to MTHF significantly. The bimetallic catalysts Cu–Ni/Al2O3–ZrO2 containing 10 wt% Ni and 10 wt% Cu gave 99.8% MTHF selectivity at full conversion of LA when the Al : Zr ratio was 9 : 1. The outstanding catalytic performance of the catalyst is related to the mesoporous structure, the acidic properties of the support and the synergistic effect between Cu and Ni. The catalyst could be reused five times without a considerable loss of catalytic activity and selectivity.
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高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Mengke Liu,Yingnan Zhao,Huawang Zhao,Xianghui Li,Yuhan Ma,Xin Yong,Hong Chen,Yongdan Li
A number of M-Cu-ZSM-5 (M = La, Ni, La-Ni) samples were prepared via an aqueous solution ion-exchange method. The co-doping with Ni and La into a Cu-ZSM-5 catalyst enhanced the NO decomposition activity in a temperature range 350–550 °C. The characterization results indicate that doping with La effectively improved the dispersion of the Cu species forming more Cu 2+ ions in the sample, while the effect of Ni is likely to facilitate the implantation of Cu 2+ to form (Cu 2+ -O 2– -Cu 2+ ) 2+ dimers. The synergistic effect of La and Ni contributes to the increased (Cu 2+ -O 2− -Cu 2+ ) 2+ content in the co-doped sample, thus enhancing the NO decomposition activity.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Yulin Huang,Xike Tian,Yulun Nie,Chao Yang,Yanxin Wang
Cu(II) doped mesoporous MnO 2 (Cu-MnO 2 ) was prepared to establish an intimate functional link between the structure substitution and catalytic peroxymonosulfate (PMS) activation. Based on the characterization of powder X-ray diffraction (XRD), N 2 adsorption-desorption measurement, scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), Cu-MnO 2 had a typical long range ordered mesoporous structure and Cu was successfully introduced in octahedral framework. It exhibited excellent catalytic activity and stability for the phenol degradation by PMS. Phenol was always efficiently degraded over Cu-MnO 2 at a pH range of 3.5–9.0. For example, the reaction rate constant at pH 7.0 was 0.073 min −1 , which was two times higher than that of MnO 2 (0.039 min −1 ). Importantly, 1 O 2 was identified as the primary reactive species in Cu-MnO 2 /PMS system. X-ray photoelectron spectroscopy (XPS) confirmed that more exposed surface oxygen defects due to Cu doping were responsible to the enhancement of PMS activation for phenol degradation. The results of PMS decomposition and oxygen evolution indicated that surface oxygen defects lower the reaction energy barrier of PMS decomposition by generating 1 O 2 via the energy trapping by oxygen. Finally, the heterogeneous PMS activation mechanism over Cu-MnO 2 was proposed.
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PubMed
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2018
·Vol. 48
·期 1
·286-295
·
IF 1.566
Zhang Chi,Xia Yong,Lian Linyuan,Fu Xiaoming,Yin Liping,Zhang Jianbing,Luo Wei,Miao Xiangshui,Zhang Daoli
Copper indium sulfide (CIS) quantum dots (QDs) are attractive as potential optoelectronic devices, since they have large absorption coefficients across a broad spectral range, size- and composition-tunable photoluminescence from the visible to the near-infrared, and low toxicity. However, CIS QDs should be hydrophilic in certain applications. In this present work, hydrophilic CIS and CIS/ZnS colloidal QDs were synthesized by a one-pot environmentally-friendly route employing N , N -dimethylformamide (DMF) as the solvent and in situ generated H 2 S as the sulphur precursor. The effect of stoichiometry was investigated by varying the feeding molar ratios of Cu/In, which did not affect the crystalline structure of the CIS colloidal QDs, while the optical property was influenced significantly. With the decrease of the feeding molar ratios of Cu/In, the band gap of the resulting CIS colloidal QDs had blue-shifts and relative photoluminescence quantum yield of the corresponding CIS/ZnS colloidal QDs increased monotonically.
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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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