查找使用阿拉丁产品的科研文献

Rational design, two-step synthesis of Cu2GeS3 crystal with enhanced thermoelectric performance by Te alloying

Hu Zeqing,Xu Huihong,Lin Yangjian,Liu Yu,Xu Junsheng,Li Zhou,Song Jiming

Currently, Cu 2 GeS 3 has been obtained through solid-state reaction. However, the pure phase Cu 2 GeS 3 synthesized still faces challenges due to the low boiling point of the sulfur element. Herein, we have prepared pristine Cu 2 GeS 3 by a two-step method. Firstly, the pure phase GeS 2 was synthesized by solvothermal method and then used the freshly as-synthesized GeS 2 as raw material to react with copper powder to fabricate pure phase Cu 2 GeS 3 . Further, the thermoelectric properties of Cu 2 GeS 3 crystal have been explored. At room temperature, the electric resistance value measured by multimeter was ~ 2634 Ω for intrinsic Cu 2 GeS 3 crystal, which exceeded the instrument (electrical conductivity/Seebeck coefficient) test range of 0–2000 Ω, so there is no relevant report in the thermoelectric field about Cu 2 GeS 3 crystal. In order to improve its conductivity, Cu 2 GeS 3 crystal is alloyed with a small amount of Te powder to obtainable Cu 2 GeS 3− x Te x samples, which have obvious thermoelectric properties. By adjusting the content of Te, finally, the electrical conductivity of the Cu 3 GeS 2.6 Te 0.4 sample reached 364.20 S m −1 and the figure-of-merit ZT max value of ~ 0.12 were obtained at 816 K.

Novel closed-cycle reaction mode for totally green production of Cu1.8Se nanoparticles based on laser-generated Se colloidal solution

Zhangyu Gu,Yisong Fan,Yixing Ye,Yunyu Cai,Jun Liu,Shouliang Wu,Pengfei Li,Junhua Hu,Changhao Liang,Yao Ma

Non-stoichiometric copper selenide (Cu2 – xSe, x = 0.18 ∼ 0.25) nanomaterials have attracted extensive attentions due to their excellent thermoelectric, optoelectronic and photocatalytic performances. However, efficient production of Cu2 – xSe nanoparticles (NPs) through a green and convenient way is still hindered by the inevitable non-environmentally friendly operations in common chemical synthesis. Herein, we initially reveal the coexistence of seleninic acid content and elemental selenium (Se) NPs in pulsed laser-generated Se colloidal solution. Consequently, we put forward firstly a closed-cycle reaction mode for totally green production of Cu1.8Se NPs to exclude traditional requirements of high temperature and toxic precursors by using Se colloidal solution. In such closed-cycle reaction, seleninic acid works as the initiator to oxidize copper sheet to release cuprous ions which can catalyze the disproportion of Se NPs to form {{\rm{SeO}}}_{3}^{2-} and Se2– ions and further produce Cu2 – xSe NPs, and the by-product {{\rm{SeO}}}_{3}^{2-} ions promote subsequent formation of cuprous from the excessive Cu sheet. In experiments, the adequate copper (Cu) sheet was simply dipped into such Se colloidal solution at 70 °C, and then the stream of Cu1.8Se NPs could be produced until the exhaustion of selenium source. The conversion rate of Se element reaches to more than 75% when the size of Se NPs in weakly acidic colloidal solution is limited between 1 nm and 50 nm. The laser irradiation duration shows negative correlation with the size of Se NPs and unobvious impact to the pH of the solution which both are essential to the high yield of Cu1.8Se NPs. Before Cu sheet is exhausted, Se colloidal solution can be successively added without influences to the product quality and the Se conversion rate. Such green methodology positively showcases a brand-new and potential strategy for mass production of Cu2 – xSe nanomaterials.

A sustainable and environmental benign catalytic process for the production of valuable flavors and fragrances from lignin platform chemicals

Xue-Qi Wang,Zhe-Hui Zhang,Xiaohong Ren,Zeming Rong,Zhuohua Sun,Tong-Qi Yuan

Recent achievements in lignin depolymerization deliver various platform chemicals with high yields and provide great potential for further upgrading to value-added high-end products. 4-propylguaiacol as one of the most widely reported products via lignin-first depolymerization approach has been upgraded to a lot of valuable chemicals including polymer and pharma intermediates. In this work, we moved the focus to the field of flavors and fragrances, and proposed an environmental-friendly synthesis route to get the alternative of 4-tert-butylcyclohexyl acetate (an important fragrance ingredient with annual production of more than 1000 metric tonnes). The key for the methodology is the design and development of the Raney NiCu catalyst which prepared by ball milling and dealloying process. The obtained catalysts show improved activity compared to widely used Raney Ni catalyst and the highest yield of 87.8% for 4-propylcyclohexanol could be achieved at 160 °C when use 2-propanol as hydrogen donor. The second step aims to get 4-propylcyclohexyl acetate via esterification of 4-propylcyclohexanol with acetic acid. This could be proceeded at 90 °C via Amberlyst-15 catalyst with the highest yield of 88.3%. The proposed process presents the potential to produce the biobased flavors and fragrances in a sustainable way.

Multiple reinforcement of chloride ion on oxidizing acetaminophen with zero-valent copper particles: In-site formation and catalysis of hydrogen peroxide

Xin Liu,Peng Xu,Shiqi Xie,Lei Wang,Zhuoyu Yang,Pengfei Zhu,Jingwei Ma,Qiulai He,John C. Crittenden

Zero-valent copper particles (Cu 0 ) used to degrade pollutant due to its in-site generation and activation of hydrogen peroxide (H 2 O 2 ), while the disproportionation of Cu + limited the efficacy. In this study, spiking chloride ion (Cl − ) into zero-valent copper (Cu 0 ) system (Cl − /Cu 0 system) enhanced greatly acetaminophen degradation. The addition of Cl − not only reduced the dismutation reaction of Cu + , but also helped the comproportionation reaction of Cu 0 and Cu 2+ , leading to much generation of Cu + and H 2 O 2 . Hydroxyl radical ( OH) and reactive chlorine species were identified as the dominant reactive oxidants in the Cl − /Cu 0 system with its contribution ratio of degrading acetaminophen being respectively 73.4 % and 23.8 %. In the Cl − /Cu 0 system, Cu + was released by H + corrosion from Cu 0 , and then Cu + coupled with Cl − forming Cu-Cl complexes; Meanwhile, the reaction of O 2 and the species of Cu + (e. g. Cu-Cl complexes and Cu + ) produced H 2 O 2 and, then the species of Cu + catalyzed H 2 O 2 to form OH; Thereinto, partial OH was shifted by Cl − to reactive chlorine species. Except for fulvic acid , coexisting substrates such as sulphate, nitrate and phosphate ions had no obvious inhibition impact on oxidizing acetaminophen in the Cl − /Cu 0 system. Furthermore, the Cl − /Cu 0 system presented a good removal rate of acetaminophen in three actual water samples. Moreover, three kinds of dyes and painkillers was removed over 78 % in the Cl − /Cu 0 system. The residual total dissolved copper was under II-level of environmental quality standards for surface water in China by alkali precipitation and filtration after reaction. Therefore, the study provided a new idea to enhance Cu 0 for the purification of pollutants.

Rapid and highly selective capture of U(VI) from water by copper phosphate

Junxiang Tang,Yu Lei,Xiaoqin Nie,Ziyue Gao,Ning Pan,Xiaoan Li,Hao Zou,Long Li

The removal of highly hazardous U(VI)-containing contaminants of concern has been a major issue for effluent discharge and ecological protection because current some inorganic adsorbents lack ion selectivity and are economically viable. Inspired by these limitations, here we reported a simple and controlled technique for the synthesis of copper phosphate (CP) that combines chemical oxidation with in-situ precipitation, able to selectively capture uranium (VI) ions. The resulting CP has been analyzed using powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy , infrared spectroscopy , and X-ray photoelectron spectroscopy. Adsorption experiments with U(VI) show that CP quickly adsorbs U(VI) from acidic water within 1 min, with a high removal efficiency of up to 97.8%. A maximum adsorption capacity of 1000 mgU g −1 adsorbent can be achieved at pH 3.0. Importantly, the selective adsorption experiments for a total of 11 metal ions show that the U(VI) capture is very effective, with an adsorption capacity of 1.64 mmol g −1 for U(VI) and a total adsorption capacity of 4.89 mmol g −1 for Ln-An metal ions . Finally, XRD and XPS results reveal that the underlying mechanism for U(VI) capture is driven through the dissolution-precipitation and surface complexation. Overall, this work proposes a new metal ion trapping agent that may find potential applications in the fields of water purification and environmental remediation.

Catalytic oxidation of 4-acetamidophenol with Fe3+-enhanced Cu0 particles: In-site generation and activation of hydrogen peroxide

Xin Liu,Peng Xu,Zhuoyu Yang,Pengfei Zhu,Lei Wang,Shiqi Xie

Cu 0 coupled with O 2 was used to degrade contaminant due to in-site generation and catalysis of H 2 O 2 , while the low reactivity and active dismutation reaction of Cu + refrained the performance at acidic condition. In this study, the removal rate of 4-acetamidophenol increased from 27 % to 83.4 % with Fe 3+ spiked into the Cu 0 system within 60 min •OH was the primary reactive species in the Fe 3+ /Cu 0 system. In the Fe 3+ /Cu 0 system, Cu 0 was corroded to form Cu + by H + and O 2 , and then Cu + interacted with O 2 generating H 2 O 2 , and meanwhile Fe 3+ was reduced to Fe 2+ by Cu + and Cu 0 ; Consequently, Cu + and Fe 2+ induced H 2 O 2 to produce •OH, but Fe 2+ was easier to catalyze H 2 O 2 than Cu + at acidic pH. Except for fulvic acid , common water matrix including sulfate ion, phosphate ion, chloride ion and nitrate ion had no inhibition effect on the degradation of 4-acetamidophenol in the Fe 3+ /Cu 0 system. over 62 % of 4-acetamidophenol in tap water , Hou-lake water and well water was greatly oxidized by the Fe 3+ /Cu 0 system. Furthermore, the amount of total dissolved copper decreased to 0.895 mg/L by the method of alkali precipitation in the Fe 3+ /Cu 0 system. The study provided a theoretical direction to the Fe 3+ -enhanced Cu 0 system for purifying wastewater.

Synergistic effects of tungsten coating on the microstructure, thermophysical and mechanical properties of graphite flakes reinforced copper matrix composites

Xiaozhen Wang,Yishi Su,Qiubao Ouyang,Di Zhang

With the rapid development of the miniaturization and high-integration of electronic devices, conventional thermal conductive materials cannot ensure the safety and reliability of the high-power devices in working environments. It is urgent to develop thermal management materials with excellent thermophysical and mechanical properties . In this work, the tungsten-coated graphite flakes (GFs(W)) were prepared by the immersion reduction, and the GFs(W) reinforced copper matrix composites (GFs(W)/Cu composites) were prepared by the vacuum hot-pressing sintering. Based on the microstructure and surface analysis, the W coating obtained at 900 °C and 200 g/L AMT appears the excellent surface structure and interfacial adhesion, which transfer the interfacial bonding from mechanical combination to mechanical-metallurgical synergy between the GFs and Cu. In addition, the volume fraction of W coating has a threshold to improve properties of the GFs(W)/Cu composites, in which the GFs(6 W)/Cu composites show the outstanding comprehensive performance: the in-plane thermal conductivity and flexural strength are 879.0 ± 10.0 Wm −1 K −1 and 166.9 ± 3.4 MPa respectively, which are improved by 22.3% and 356.0%, and the lowest coefficient of thermal expansion is 4.3 ± 0.5 ppmK −1 . To sum up, it provides an effective way to develop novel structural and functional integrated graphite/copper composites for thermal management.

A green slurry electrolysis to recover valuable metals from waste printed circuit board (WPCB) in recyclable pH-neutral ethylene glycol

Kaixin Liu,Shuquan Huang,Yangxin Jin,Lan Ma,Wen-Xiong Wang,Jason Chun-Ho Lam

The continuous growth of e-waste necessitates an efficient method to recover their metal contents to improve their recycling rate. The successful recovery of the metallic component from Waste Electrical and Electronic Equipment (WEEE) can generate great economic benefits to incentivize the industrial recycling effort. In this study, we report the use of slurry electrolysis (SE) in pH-neutral ethylene glycol (EG) electrolyte to extract and recover the metallic component from waste printed circuit broad (WPCB) powder. The system operates at room temperature and atmospheric pressure, and the electrolyte can be recycled multiple times with no signs of chemical degradation . The EG electrolyte system can oxidize the metallic component without triggering anodic gas evolution, which allowed us to incorporate a reticulated vitreous carbon (RVC) foam anode to maximize the capture and oxidation of the metal content. The system demonstrated up to 99.1% Faraday efficiency for the cathodic metal deposition and could recover Cu from the WPCB powder in a selective manner of 59.7% in the presence of 12 other metals. The SE reaction system was also scalable and displayed no compromises on the Cu recovery selectivity . With the ability to leach and recover metallic content from WPCB in a mild and chemically benign condition, the SE system displayed much promise to be adapted for industrial-scale metal recovery from WPCB.

Laser-Engraved Boron-Doped Diamond for Copper Catalyzed Non-Enzymatic Glucose Sensing

Qian Gao,Wangyang Zhang,Chaopeng Zhao,Weishan Yan,Suqin Han,Yanyan Li,Qiao Liu,Xi Li,Duo Liu

Robust and high-performance electrochemical electrodes for non-enzymatic glucose sensing are in constant demand. Herein, a hierarchical nonenzymatic glucose sensing electrode on boron-doped diamond (BDD) is fabricated using high-speed laser engraving and pulsed electrodeposition of Cu nanostructures. The obtained electrode contains a densely packed Cu nanoflake (CuNF) array periodically decorated on the laser-engraved BDD. The hierarchical nanoarchitecture combines the d-band catalytic activity of the CuNFs with the low capacitive background current of the engraved BDD substrate, thus enabling fast, precise, and high signal-to-noise ratio detection of trace glucose. Outstanding performances that combine high sensitivity of 2119 µA cm –2 m m –1 , ultrafast response time of <1 s, and low detection limit of 0.2 × 10 −6 m are experimentally demonstrated. Furthermore, the electrode exhibits excellent cyclicality and anti-interference ability, and maintains 90% of its initial responsivity after being stored in air for >8 months, indicating great stability for practical usage.

Brazing of TiAl and Ti2AlNb alloys using high-entropy braze fillers

Z. Sun,X.X. Zhu,H.Z. Chen,L.X. Zhang

To address the excessive formation of brittle compounds when brazing TiAl alloys, a TiZrHfCoNiCu high-entropy brazed filler was developed to realize the brazing of TiAl/Ti 2 AlNb couples. The TiAl/Ti 2 AlNb brazed joints can be divided into 4 zones, i.e., 2 diffusion zones at the TiAl/braze filler, Ti 2 AlNb/braze filler interfaces and 2 zones divided inside the brazed seam. α 2  + γ-TiAl were the main reaction products formed at the TiAl/braze filler interface and α 2 + Ti 0.5 Al 0.12 Nb 0.38 were the main reaction products at the Ti 2 AlNb/braze filler interface. Effects of brazing temperatures on the interfacial microstructure and mechanical properties of the TiAl/Ti 2 AlNb brazed joints were investigated. When brazing at 1100°C/15 min, the highest shear strength can reach 157 MPa (room temperature), and 123 MPa (650°C) respectively. The relationship between the microstructure and the corresponding mechanical response were discussed in detail. This research can offer new insights on developing desirable brazing filler when joining TiAl and TiAl based alloys.

Comparative study of the electrocatalytic N2 reduction property of a Cu4 cluster with μ2-/μ3-OH and a Cu2 complex with μ2-OH

Wei Wang,Jing-Zhe Li,Shi-Jian Luo,Zi-Xuan Yao,Kuan-Guan Liu

Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production. Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production.

Leakage Rate Control of Magnetic Powder Seals by Lubricant Coatings on Magnetic Nanoparticles and Flow Field Simulation

Zhenghao Li,Decai Li