ELECTROCHIMICA ACTA
·
2014
·
IF 4.086
Shaojie Li,Daojian Cheng,Xiangguo Qiu,Dapeng Cao
A core-shell Cu@Pd nanowire with enhanced activity and stability for formic acid oxidation (FAO) was prepared by decorating Pd shell on the surface of Cu nanowire. Detailed characterization (XRD, TEM and HAADF-STEM) results confirm that the prepared nanowires are of Cu@Pd core-shell structure with enlarged surface areas. The catalytic activity of Cu@Pd/C (2197.88 mA/mg at 0.257 V) toward FAO is about 4 times higher than that of the commercial Pd/C (547 mA/mg at 0.257 V). The enhanced activity of the catalyst may mainly result from the synergetic effect of Cu and Pd, which was confirmed by density-functional theory (DFT) calculations.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zelong Wang,Yanan Zhang,Jungang Yi,Ning Cai,Jia Guo
Heat accumulation has emerged as a critical issue that affects the performance and reliability of modern electronic devices in their evolving toward miniaturization, high power density and high integration. The application of thermal interface materials (TIMs) as a thermal management strategy is commonly employed to tackle this problem. Herein, we report the development and characterization of highly thermally conductive but electrically insulating Cu@Al 2 O 3 /epoxy composites. Stemming from the excellent thermal conductivity of Cu, the Cu@Al 2 O 3 /epoxy composites exhibit thermal conductivity of 1.32 W/m·K at 10 vol% filler content , which is nearly 7 times higher than that of the epoxy resin . Simultaneously, the Cu@Al 2 O 3 /epoxy composites still retain a high electrical resistivity of 2.3 × 10 13 Ω·cm, which is 6 orders of magnitude greater than that of Cu/epoxy composites without Al 2 O 3 barrier layers, because the dense nanoscale insulating Al 2 O 3 shell effectively inhibits the electron transfer . In addition, the Cu@Al 2 O 3 /epoxy composites possess lower dielectric constant and dielectric loss , and better mechanical properties than those of Cu/epoxy composites.
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Advanced Sensor and Energy Materials
·
2023
·
IF 0
Di Chen,Xiao-Yu Shen,Rong-Hua Zhang,Luo-Yi Yan,Zheng Cheng,Gui-Xian Tian,Dong-Hai Lin,Xin-Wen Zhou
In the face of environmental pollution and an energy shortage, how to reduce the cost of a noble metal catalyst in clean energy such as the fuel cell system and improve its electrocatalytic performance is one of the hot issues in this field. Here, a facile stepwise co-reduction route for synthesizing a series of PdFe/Cu catalysts with surface reconstruction is investigated and the ethanol oxidation reaction (EOR) performance is explored. The greater exposure of Pd active sites makes it excellent in EOR in alkaline media compared to the homemade and commercial Pd black catalyst. The mass activity of PdFe/Cu (794.97 mA mg −1 Pd ) is 2.52 times that of the Pd black catalyst (315.64 mA mg −1 Pd ). This kind of PdFe/Cu catalyst shows enhanced mass current density (255.66 mA mg −1 Pd ) after the 1800 s chronoamperometry test and only exhibits a decay of 1.4% after accelerated 500-cycle measurement. The enhanced EOR performance may be due to the change in the electronic structure of Pd caused by synergistic and strain effects among Pd, Fe, and Cu. This work provides an effective and kindly strategy to synthesize electrocatalysts with superior activity and durability in relation to EOR.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2023
·Vol. 170
·期 7
·077509
·
IF 3.9
Qi Wang,Wenjing Liu,Jinjin Zhang,Jianying Qu
In this work, Cu/N-C derived from MOF composites were synthesized and characterized by SEM, XRD, FTIR, XPS and EIS, which was modified on the glassy carbon electrode (GCE) to construct a novel electrochemical sensor (Cu/N-C/GCE). Due to the good electrical conductivity and abundant catalytic active sites of Cu/N-C, Cu/N-C/GCE exhibited excellent electrocatalytic performance for catechol (CC) and hydroquinone (HQ) with the oxidation peak potential difference of 112 mV. The proposed sensor could realize the simultaneous detection of CC and HQ successfully. Under optimal conditions, the redox peak currents of both CC and HQ have good linear relationship with their concentrations in the ranges of 0.50–100.00 μM and 0.50–150.00 μM with the detection limits for CC and HQ of 0.12 μM and 0.09 μM, respectively. At the same time, the sensor exhibits good stability, reproducibility and selectivity in the analysis of practical samples.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2023
·
IF 8.4
Li Yang,Qixin Chen,Yiheng Yuan,Xishun Peng,Xinghua Li,Cheng Zuo,Zhangyu Zhou,Zhongchen Bai
Detecting γ-aminobutyric acid (GABA) in the mammalian body is vital for diagnosing neurological disorders. Here, we introduced a novel SERS sensor based on metal-semiconductor heterojunction ZnO/Cu@Ag substrate for highly sensitive detecting GABA molecules. The ZnO/Cu@Ag substrate fully leverages the electromagnetic field enhancement effect and the chemical enhancement effect of metal-semiconductors heterojunction, exhibiting an excellent enhancement factor of 2.23 × 10 6 and a low limit-of-detection (LOD) of 3.84 nM for GABA molecules in water. Moreover, the ZnO/Cu@Ag substrate could recognize 10 nM GABA molecules in human serum. This GABA SERS sensor provides a reliable tool and technological support for research and applications in neuroscience and medicine.
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RSC Advances
·
2018
·Vol. 8
·期 11
·6110-6119
·
IF 2.936
Chengkai Pang,Yuqun Zhuo,Qiyu Weng,Zhenwu Zhu
The activity and hydrothermal stability of Cu/SAPO and xMn–2Cu/SAPO for low-temperature selective catalytic reduction of NOx with ammonia were investigated. An ion-exchanged method was employed to synthesize xMn–2Cu/SAPO, which was characterized by N2 adsorption, ICP-AES, X-ray diffraction (XRD), NH3-temperature programmed desorption (NH3-TPD), NO oxidation, X-ray photoelectron spectrum (XPS), UV-vis, H2-temperature programmed reduction (H2-TPR) and diffuse reflectance infrared Fourier transform spectra (DRIFTS). 2Mn–2Cu/SAPO and 4Mn–2Cu/SAPO showed the best SCR activity, in that at 150 °C NO conversion reached 76% and N2 selectivity was above 95% for the samples. NO oxidation results showed that the 2Mn–2Cu/SAPO had the best NO oxidation activity and the BET surface area decreased as manganese loading increased. XRD results showed that the metal species was well dispersed. NH3-TPD showed that the acid sites have no significant influence on the SCR activity of xMn–2Cu/SAPO. H2-TPR patterns showed good redox capacity for xMn–2Cu/SAPO. UV-vis and H2-TPR showed that the ratio of Mn4+ to Mn3+ increased as manganese loading increased. XPS spectra showed a significant amount of Mn3+ and Mn4+ species on the surface and addition of manganese increased the ratio of Cu2+. The promotion effect of manganese to 2Cu/SAPO comes from the generation of Mn3+ and Mn4+ species. Deduced from the DRIFTS spectra, the Elay–Rideal mechanism was effective on 4Mn–2Cu/SAPO.
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Catalysis Science & Technology
·
2020
·Vol. 10
·期 13
·4412-4423
·
IF 5.721
Qiang Liu,Zhenbo Zhao,Masahiko Arai,Chao Zhang,Ke Liu,Ruhui Shi,Peixuan Wu,Zhuangqing Wang,Weiwei Lin,Haiyang Cheng,Fengyu Zhao
The transformation of γ-valerolactone (GVL) into 1,4-pentanediol (1,4-PDO) and 2-methyltetra-hydrofuran (2-MTHF) in the presence of H2, one of the useful biomass conversion and utilization processes, was investigated with monometallic Cu/Al2O3 and bimetallic ZnCu/Al2O3 catalysts. A 10 wt% Cu-loaded monometallic catalyst produced 1,4-PDO and 2-MTHF in comparable quantities at a medium conversion (∼50%). When Zn was added in a range of Zn/Cu molar ratios of up to 2, in contrast, the catalysts yielded 1,4-PDO in a high selectivity of about 97% at low and high conversion levels. In addition, the 1,4-PDO selectivity over the ZnCu/Al2O3 catalysts remained almost unchanged during recycled runs. That is, the addition of Zn to Cu/Al2O3 switched the product selectivity and improved the catalyst stability and reusability. Furthermore, the physicochemical properties of the catalysts were characterized by several methods including XRD, TEM, TPR, XPS, FTIR of adsorbed pyridine, and so on. On the basis of those results, the relationships between the catalytic performance (activity, selectivity, and reusability) and the catalyst structural features were discussed.
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INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2022
·Vol. 46
·期 13
·18562-18572
·
IF 4.672
Bo Tang,Hefei Fan,Qianfeng Liu,Qiang Zhang,Min Liu,Erdong Wang
Summary Aqueous zinc batteries (AZBs) hold great promise for advancing applications in next-generation energy storage devices because of their high safety, high energy density, and low cost. However, zinc metal anodes have greatly impeded the application in AZBs due to their poor cycle performance. Short lifespan, which is caused by dendritic growth, deformation, corrosion, and competing hydrogen evolution, is very tricky. Herein, a stable Sn@Cu foam, prepared by plating tin on copper foam, is reported as the substrate of Zn anodes. We evaluate the quality of plating tin layers, which are prepared by using different tin salt solutions, and Na 2 SnO 3 solution is eventually selected. Electrochemical tests show that Sn@Cu foam can not only inherit the merits of Cu foam but also suppress hydrogen evolution reaction and lower the initial heterogeneous nucleation barrier of deposited Zn. Moreover, in situ observation by optical microscope demonstrates that Zn dendrite growth on Sn layer is suppressed during the plating-stripping process. As a result, a compact Zn layer on Sn@Cu foam is obtained (Zn/Sn@Cu foam), symmetrical cells display superior cycling life of 1800 h at 1 mA cm −2 for 1 mAh cm −2 , and full cells with VO 2 cathode deliver remarkably better cycling stability and longer lifespan.
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RSC Advances
·
2019
·Vol. 9
·期 23
·13065-13076
·
IF 3.049
Yuzhe Zhang,Tingting Bian,Da Xia,Dandan Wang,Yi Zhang,Xudong Zheng,Zhongyu Li
Although bio-materials are widely used for the adsorption of heavy metal ions, they have low specific surface area, slow adsorption rates, and poor selectivity. To overcome these limitations, in this study, we report a 3D-ordered macroporous ion-imprinted chitosan film (3DOM-IICF); the 3DOM-IICF coupled with a colloidal crystal template and ion imprinting (IIP) technology has been used to absorb copper ions (Cu(II)) present in water. Moreover, polystyrene (PS) micro-spheres and copper templates were added to form a three-dimensional ordered macroporous structure and ion-imprinted sites, respectively. Finally, the film was formed by drying. Adsorption experiments showed the removal of Cu(II) from the 3DOM-IICF in an aqueous solution. The 3DOM-IICF exhibited good adsorption performance under neutral conditions of pH = 7.0, and the adsorption efficiency was high. The maximum adsorption capacity of the 3DOM-IICF was 261.31 mg g−1. The adsorption processes were more consistent with the pseudo-second-order kinetic model and the Langmuir isotherm. The 3DOM-IICF exhibits superior selective adsorption of Cu(II). Moreover, the 3DOM-IICF could be regenerated multiple times, reused as an adsorbent and maintained high adsorption capacity. This kind of imprinted template method has important significance in the selective adsorption of pollutants in bio-materials and is worthy of in-depth research.
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Soft Matter
·
2021
·Vol. 17
·期 17
·4550-4558
·
IF 3.679
Zhaoyu Liu,Dong Yao,Lin Ai,Huiwen Liu,Shitong Zhang,Hao Zhang
Fluorescent Cu nanoclusters (NCs) have shown potential in lighting and display, because Cu is cheap and easily available. Despite recent successes in improving the emission intensity of Cu NCs on the basis of aggregation-induced emission enhancement and self-assembly-induced emission enhancement, the difficulty in tuning the emission color sheds the doubt for achieving high-performance white light-emitting diodes (WLEDs). In this work, halogen effects are utilized to tune the emission color of Cu nanocluster self-assembly nanosheets (NSASs). By altering the adsorbed halogens from Cl, Br to I, the emission peak of Cu NSASs is tunable from 495 to 674 nm. In this context, halogen atoms are capable of improving the charge transfer and molecular spin coupling of Cu NCs, and thereby narrow the S0T1 gap and facilitate the intersystem crossing of excitons from a singlet to triplet state. As a result, emission spectra redshift and the population of the exiton recombination via the triplet state pathway is increased, which leads to the improvement of the photoluminescence quantum yield (PLQY). By simply introducing and/or mixing different types of cuprous halides, Cu nanocluster co-assembly nanosheets (NCASs) with full-color emission are obtained. The as-prepared Cu NSASs and NCASs are further employed to fabricate monochrome and white LEDs.
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Nano Research
·
2018
·Vol. 11
·期 5
·2612-2624
·
IF 7.994
Gao Daowei,Li Shuna,Song Guolong,Zha Pengfei,Li Cuncheng,Wei Qin,Lv Yipin,Chen Guozhu
Shape-controlled synthesis of Pt−Cu alloy nanocrystals (NCs) with unique geometries is of great importance in the rational design and deterministic synthesis of highly active electrocatalysts. Herein, Pt−Cu alloy NCs with concave octahedron (COH), porous octahedron (POH), yolk–shell (YSH), and nanoflower (NOF) structures were fabricated by altering the sequential reduction kinetics in a one-pot aqueous phase. The effect of the reaction kinetics on the formation of Pt−Cu bimetallic NCs with different morphologies was analyzed quantitatively. The concentrations of glycine and metal cation are demonstrated to play a key role in the reduction of Pt(IV) and Cu(II) ions; these significantly affected the morphology of Pt−Cu NCs. These Pt−Cu alloy NCs exhibit substantially enhanced catalytic activity and durability for methanol and formic acid oxidation compared to the commercial Pt/C catalyst. Specifically, the COH and NOF Pt−Cu NCs with more step atoms, intragranular dislocations, and protrusions showed superior electrochemical properties than those of POH and YSH Pt−Cu NCs. The structure–property relationship between the Pt−Cu NCs and their electrochemical performances was also investigated in depth.
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Catalysts
·
2022
·Vol. 12
·期 4
·426
·
IF 4.501
Jinyun Liao,Yujie Wu,Yufa Feng,Haotao Hu,Lixuan Zhang,Jingchun Qiu,Junhao Li,Quanbing Liu,Hao Li
Promoting the activity of heterogeneous catalysts in the hydrolysis of ammonia borane for hydrogen production is still a challenging topic for researchers in the hydrogen energy and catalysis fields. Herein, we present a universal, simple and efficient strategy to boost the catalytic performance toward AB hydrolysis by mixing Co- and Cu-based catalysts for the first time. Synergistic catalysts with remarkably enhanced activity can be obtained by mixing a Co-based catalyst and a Cu-based catalyst together, such as Co3O4and Cu3(MoO4)2(OH)2, Co3O4and Cu3(PO4)2,Co3(PO4)2and Cu3(MoO4)2(OH)2, Co3(PO4)2and Cu3(PO4)2, and CuO and Co3O4. For example, the turnover frequency (TOF) for the mixture catalyst of Co3O4and Cu3(MoO4)2(OH)2with a mass ratio of 4:1 is up to 77.3 min−1, which is approximately 11.5 times higher than that of the sum of Co3O4and Cu3(MoO4)2(OH)2. The reasons for these findings are discussed in detail. The observations and conclusions in this work may provide a guideline for promoting the hydrolysis of ammonia borane through a simple and effective approach.
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