查找使用阿拉丁产品的科研文献

Fabrication and Sintering Behavior of Nano Cu–Ag Composite Paste for High-Power Device

Weishan Lv,Jiaxin Liu,Yun Mou,Yongjie Ding,Mingxiang Chen,Fulong Zhu

Nanoflower core-shell Cu@Pd catalysts for glycol oxidation reaction with an enhanced performance

Jianguo Yu,Zehui Yu,Yunling Jia,Ting Ran,Ming Song,Yanshuang Zhang,Qing Wang,Yuning Qu,Lili Wang

Direct alcohol fuel cells' performance is significantly affected by the phase and composition of the catalyst, thereby the development of high-performance alcohol oxidation catalysts is essential. In this study, PVA preparation was used for the first time to create PdCu core-shell nanoflowers with a high electrochemically active surface area and a potent synergistic effect. Notably, the presence of PVA causes Pd and Cu nanoparticles with different reduction rates to form a core-shell structure, and the Pd nanoparticles continue to migrate regularly under the action of PVA, forming a flower-like morphology with a high degree of branching. Cu@Pd 22.3 catalyst exhibited 13 times higher catalytic performance (4353.04 mA mg Pd −1 ) than Pd/C (334.09 mA mg Pd −1 ) in ethylene glycol oxidation reaction. The Cu@Pd 22.3 catalyst also exhibits higher stability than commercial Pd/C in stability tests lasting up to 20,000 s. This core-shell combination and highly branched structural design result in more active sites for fast ion adsorption/desorption,offering an original method to improving the activity and endurance of polyol oxidation.

Highly efficient electrocatalysis dechlorination of Dichloromethane over Single-Atom Cu/Co3O4-β spinel nanofibers

Jing Yang,Shiying Fan,Xinyong Li,Yiyuan Tao,Jingang Wang,Guohua Chen

Electrochemical selective dechlorination of dichloromethane (DCM) to chloromethane is a promising and sustainable strategy of resources. However, the current lack of high-performance electrocatalysts and complicated dechlorination mechanisms pose significant challenges. In this study, we report a series of Cu single-atom catalysts (SACs) supported on Co 3 O 4-β spinel with a tube-in-tube nanofiber structure, denoted as Cu x SACs/Co 3 O 4-β , where x represents the theoretical Cu loading (0.26 wt%, 0.30 wt% and 0.50 wt%). These catalysts effectively dechlorinate DCM, producing high-value hydrocarbons like chloromethane and methane. Notably, Cu 0.30 SACs/Co 3 O 4-β exhibited a high chloromethane production rate (2931 μmol g −1 h −1 ) and selectivity (76%) at −2.98 V vs (Ag/AgCl/Me 4 NCl) due to the synergy of cobaltosic oxide (Co 3 O 4 ) spinel and Cu single atom. X-ray photoelectron spectroscopy and electron paramagnetic resonance experiments confirmed the presence of additional surface oxygen vacancies in Cu 0.30 SACs/Co 3 O 4-β , which improved the electrocatalysis performance for DCM dechlorination. Furthermore, a concerted dechlorination mechanism was suggested based on the transfer coefficient α . This research paves the way for the development of novel spinel electrocatalysts and the advancement of dechlorination reactions.

Dielectrophoresis-assisted removal of Cd and Cu heavy metal ions by using Chlorella microalgae

Kai Zhao,Xun Zhao,Tianbo Gao,Xuan Li,Guanqi Wang,Xinxiang Pan,Junsheng Wang

A novel dielectrophoresis (DEP)-assisted device for the bioremediation of heavy metal ions by using Chlorella microalgae is presented in this paper. To generate the DEP forces, pairs of electrode mesh were inserted in the DEP-assisted device. By applying DC electric field via the electrodes, the inhomogeneous electric field gradient is induced and the strongest non-uniform electric field exists near the mesh cross-corner. After the adsorption of Cd and Cu heavy metal ions by Chlorella , the Chlorella chain were trapped along the vicinity of the electrode mesh. Then, the effects of Chlorella concentration on the adsorption of heavy metal ions, and the applied voltage and electrode mesh size on the removal of Chlorella are conducted. In the co-existing Cd and Cu solutions, the individual adsorption ratio of Cd and Cu reaches as high as approximately 96% and 98%, respectively, showing excellent bioremediation capability of multiple heavy metal ions in wastewater. By adjusting the applied electric voltage and the mesh size, the Chlorella adsorbed with Cd and Cu are captured by negative DC-DEP effects and the removal ratio of Chlorella reach an average of 97%, providing a method for the removal of multiple heavy metal ions in wastewater by using Chlorella microalgae.

Dry sliding tribological properties of Cu-WS2 self-lubricating composites at 25–500 °C

Jianhui Yan,Yi Wang,YuanJun Guo

Cu-WS 2 composites are being used as self-lubricating materials for various engineering applications. The poor wettability between Cu and WS 2 is a main obstacle for obtaining high-performance Cu-WS 2 . In order to improve the wettability, a thin Cu layer was deposited on the surface of the WS 2 powder through an electroless plating technology. Cu-WS 2 composites were prepared via spark plasma sintering (SPS) using the mix powders of Cu and Cu-WS 2 . Microstructure, mechanical properties and tribological properties of the Cu-WS 2 composites were investigated, and that of the Cu were also comparatively studied. Results show that the WS 2 powder coated with Cu (abbreviated as WS 2 @Cu powder) improves the poor wettability between Cu and WS 2 and meanwhile the distribution of WS 2 . Cu-WS 2 composites sintered below 750 °C could reduce the reaction between Cu and WS 2 and ensure more WS 2 in the composites. Both the coefficient of friction (COF) and the wear rate of the Cu-WS 2 are lower than that of the Cu. A lubricant film leads to the excellent tribological properties as the Cu-WS 2 composites were tested at 25−200 °C. However, the disappearance of WS 2 and the formation of Cu 2 O cause to the decreasing self-lubricating performances at 300−500 °C. With an increase in the test temperature, the dominant wear mechanisms of the Cu-WS 2 composites change from adhesive wear to a mixture of abrasive and oxidation wear, and that of the Cu change from adhesive wear to a mixture of fatigue and oxidation wear.

BN/Cu/CNT nanoparticles as an efficient tri-functional electrocatalyst for ORR and OER

Jiemei Yu,Zhankun Jiang,Taizhong Huang,Chengchun Tang

Preparing economic, stable, and highly efficient non-precious-metal materials for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great significance to the development of storage technologies and energy conversion. In this manuscript, we report a novel Cu based nano-catalyst as an electrode material fabricated by complexation-reduction method. Benefit from the stable of h-NB and the good electrical conductivity of CNT , the tri-functional electrocatalyst BN/Cu/CNT displays enhanced activity towards ORR and with the high current density of 0.95 mA/cm 2 , which is comparable to that of commercial Pt/C catalyst (cathodic peak current: 1.05 mA/cm 2 ). The BN/Cu/CNT also demonstrates high catalyst activity for the OER. From the rotating disk electrode and rotating ring-disk electrode tests, the number of electrons exchanged during the ORR is revealed to be 3.92, suggesting a 4e − pathway of O 2 reduction to H 2 O. The as prepared catalyst also has good stability and superior methanol tolerance to the commercial Pt/C catalyst in alkaline medium . Thus, it is anticipated that the BN/Cu/CNT catalyst is surely helpful for providing a new space to develop Pt-free catalyst.

Coupling Ni–Cu atomic pair to promote CO2 electroreduction with near-unity CO selectivity

Yu Weiting,Zhu Jieyun,Chen Sizhuo,Tang Juntao,Ye Jiexu,Song Shuang

The electrocatalytic reduction of CO 2 towards CO is one of the most desirable routines to reduce atmospheric CO 2 concentration and maintain a global carbon balance. In this work, a novel porous NiCu-embedded ZIF-derived N-doped carbon nanoparticle (NiCu@NCNPs) catalyst has been identified as an active, highly selective, stable, and cost-effective catalyst in CO 2 reduction. A CO selectivity as high as 100% has been achieved on NiCu@NCNPs which is the highest reported to date. The particle current density of CO on NiCu@NCNPs is around 15 mA cm –2 under the optimized potential at −0.9 V vs. RHE. The NiCu@NCNPs electrode also exhibits excellent stability during the five sequential CO 2 electroreduction experiments. The superior catalytic performance of NiCu@NCNPs in CO 2 RR can be related to its microstructure with high electrochemical surface area and low electron transfer resistance. Furthermore, a kinetic analysis has shown the formation of intermediate *COOH is the rate-determining step in CO 2 RR towards CO. According to the results of density functional theory (DFT) calculations, a low Gibbs-free energy change (∆ G ) for the rate-determining step leads to the enhanced catalytic performance of CO 2 RR on NiCu@NCNPs.

Facile fabrication of bimetallic Cu–Ag binary hybrid nanoparticles and their application in catalysis

Yuxi Meng,Hanyu Gao,Shuang Li,Fang Chai,Lihua Chen

Herein, high efficiency and recyclable Cu–Ag hybrid catalyst (Trp–Cu–Ag) NPs were prepared by the hydrothermal method using L-tryptophan as a reducing agent and protecting reagent. The structure, morphology and catalytic properties of the Trp–Cu–Ag NPs were investigated in detail. The binary Trp–Cu–Ag NPs were assembled using Trp–Cu nanosheets and Ag nanoparticles through a one-step process. The developed Trp–Cu–Ag NPs show excellent catalytic performance in the reduction of nitrophenols (4-nitrophenol, 2-nitrophenol and 3-nitrophenol). Meanwhile, the Trp–Cu–Ag NPs exhibited a stable conversion efficiency of over 95% for more than 10 recycles in the reduction of 4-nitrophenol. The binary Trp–Cu–Ag NPs can also catalytically reduce K3(Fe(CN)6) in the presence of a NaBH4 aqueous solution with high efficiency. All in all, the obtained Trp–Cu–Ag NPs show potential as a catalyst in practical environmental protection applications due to their cost-effective and recyclable features.

Promoting solar-to-hydrogen evolution on Schottky interface with mesoporous TiO2-Cu hybrid nanostructures

Jiaxin Zhu,Jinyan Xiong,Gang Cheng,Weijie Li,Shixue Dou

Developing a highly efficient photocatalysis system based on a photocatalyst-cocatalyst host for the hydrogen evolution reaction has potential but is still challenging. Herein, we report enhanced splitting of water achieved by loading copper metal particles on mesoporous TiO 2 microrods through involving of dual ligand agents into the reaction system. The composition , structure, and surface characteristics of the TiO 2 -Cu hybrid were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy , and nitrogen adsorption . The formation of a Schottky contact in the interface between the Cu metal and the n -type semiconductor TiO 2 was confirmed experimentally by photo/electrochemical measurements. This Schottky junction, the TiO 2 -Cu hybrid photocatalyst , exhibited superior hydrogen evolution capability with rate of 6046 μmol g −1  h −1 , which is 23 times higher than that of pristine TiO 2 (260 μmol g −1  h −1 ). The experimental results demonstrated that efficient separation and transfer of photo-induced electron-hole pairs greatly contributed to the enhanced photocatalytic H 2 evolution. The Schottky contact between Cu and TiO 2 as well as cocatalyst characteristic of Cu play significant roles in preventing the recombination of electron-hole pairs and enhancing water splitting to form hydrogen. This study demonstrates a rational design to construct Schottky contacts in metal-semiconductor junctions to significantly boost their photocatalytic capacity.

Synthesis of Cu/Ni-La0.7Sr0.3Cr0.5Mn0.5O3–δ and its catalytic performance on dry methane reforming

Dingwen Kang,Jie Yu,Wenhui Ma,Min Zheng,Yunfei He,Pengfei Li

In this study, Cu/Ni-La 0.7 Sr 0.3 Cr 0.5 Mn 0.5 O 3– δ (LSCM) catalysts were synthesized via the citric acid-nitrate process (CNP) and chemical co-precipitation. The catalytic performance of Cu/Ni-LSCM catalysts on dry methane reforming was evaluated in a fixed-bed reactor at 550/650 °C and atmosphere pressure. Cu/Ni loading was investigated as an influencing factor, which led to 5 cases of samples according to the different Cu/Ni mass ratios. The catalysts were characterized by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), Brunauer-Emmett-Teller (BET) measurement, X-ray photoelectron spectroscopy (XPS), hydrogen-based temperature-programmed reduction (H 2 -TPR) and thermos gravimetric analyzer (TGA). The results show that the methane conversion increases, the resistance against metal sintering increases and the carbon deposition drops after the copper is introduced. This optimum performance can be obtained under Case 3 (Cu:Ni:LSCM = 1:3:6 in mass ratio).

Cu Nanoparticles Supported on Oxygen-Rich Boron Nitride for the Reduction of 4-Nitrophenol

Xinrui Jiang,Bo Han,Chenggang Zhou,Kaisheng Xia,Qiang Gao,Jinping Wu

Hexagonal boron nitride (h-BN) with a unique 2D architecture is a promising support for catalyst due to its large surface area, high thermal stability, and chemical inertness. However, the weak interaction between h-BN and active metal particles would lead to unexpected agglomeration or loss of active components. In this work, an oxygen-rich mesoporous boron nitride (BNO) support was synthesized by a two-step calcining process, on which Cu nanoparticles were dispersed via a typical adsorption–reduction procedure. The reduction of p-nitrophenol (4-NP) was successively carried out as a model reaction to determine the catalytic performance of the Cu/BNO catalyst. Excellent catalytic activity of 4-NP reduction was implemented with a reaction rate constant of 0.692 min–1, which is maintained almost intact within five cycles. First-principles calculations suggest that the superior durability of Cu/BNO is largely attributed to the weakened conjugation effect of BNO upon O doping, which strengthens the interactions between Cu nanoparticles and BNO supports. Moreover, the doping O atom would significantly enrich the electron density of Cu, which is responsible for the superior activity toward 4-NP reduction.

Cu (II) coordination modification of aramid fiber and effect on interfacial adhesion of composites

Ting Li,Zengxiao Wang,Junrong Yu,Yan Wang,Jing Zhu,Zuming Hu

In this article, active groups were introduced to the surface of aramid fiber by building a Cu2+ bridge between the aramid fiber and polyethyleneimine (PEI) to improve adhesion in composites between the aramid fiber and the matrix such as epoxy resin. The changes in the structure and properties of the aramid fiber were verified with Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and the single-fiber pull-out test. The FTIR and XPS results show a significant change in the structure and morphology of the aramid fiber after modification. The results of the single-fiber pull-out test show that the interfacial shear strength (IFSS) of epoxy composites reinforced with PEI-grafted aramid fiber increases by 48.8% compared with the IFSS of epoxy composites reinforced with untreated fiber. Thus, the proposed method can improve the interfacial bonding of composites by creating a copper ion bridge between the aramid fiber and PEI.