查找使用阿拉丁产品的科研文献

The intrinsic kinetic study on oxidation of a Cu-based oxygen carrier in chemical looping combustion

Chaohe Zheng,Mingze Su,Haibo Zhao

As the kinetic influencing factors were not considered properly in the previous studies, the obtained activation energies of copper oxidation were discrepantly ranging from 15.0 kJ/mol to 100.0 kJ/mol. The gas diffusion in the crucible and sample layer, the surface reaction and the defect diffusion of copper cations all have an impact on the conversion process of copper oxidation samples. Using the high diameter-height ratio crucible in our self-made TGA could effectively eliminate the gas diffusion in the crucible and reduce the error of the kinetic tests. Based on the previous four-step oxidation mechanism, the kinetic parameters of copper oxidation are identified using a grain-scale kinetic model, coupling with a defect transport model. The potential kinetic impact factors including the particle polydispersity, gas diffusion, defect diffusion, surface reaction and particle sintering are adequately considered in this work. First, it is found that the copper oxidation is not dominated by the defect diffusion in the solid product layer, but governed by the surface reaction in the gas–solid interface. The copper oxidation is likely to be adsorption-limited during the surface reaction in the gas–solid interface, and the intrinsic activation energy is identified as 48.0 kJ/mol. The particle-scale model is then performed to investigate the impact of physical properties of oxygen carrier particles. It can significantly accelerate the conversion rate of copper oxidation by means of decreasing the particle size and increasing the porosity. However, it is not advisable to decrease the grain size too much when preparing the oxygen carriers, for this will only increase diffusion resistance inside the particle for small grain. Finally, it can be found that in most conditions of the air reactor, Cu-based oxygen carrier with the grain size of 220–300 nm exhibits the best oxidation performance.

Fast synthesis and thermoelectric properties of BixCu2−3xSe0.95Te0.05 (x = 0, 0.001, 0.002, 0.003, 0.004)

Xue Lisha,Wang Yuan,Zhu Shuangmei,Mao Qianhui,Jia Xiaopeng,Zhang Yuewen

We have synthesized the quaternary copper selenide Bi x Cu 2−3 x Se 0.95 Te 0.05 compounds by high-pressure followed with ball milling method and investigated their thermoelectric properties. The crystal structure and element doping are characterized and verified by the X-ray diffraction, high-resolution transmission electron microscope and X-ray photoelectron spectroscopy. Compared with other samples, the samples with x  = 0.001 and 0.002 have larger layered grain size and smaller grain boundary. This may lead to the reduction of resistivity in a wide temperature range, thus realizing the optimization of electronic characteristics. The dislocation-induced lattice strain fluctuations may cause the abrupt thermal conductivity, which is contrary to the previous results. Eventually, a peak value of zT  = 1.03 at 873 K is obtained for Bi 0.001 Cu 1.997 Se 0.95 Te 0.05 and Bi 0.002 Cu 1.994 Se 0.95 Te 0.05 .

Thermal conductive proppant with self-suspension ability

Guo-Qing Xu,Xiu-Ping Lan,Si-Si Zhao,Kai-Yi Hu,Si-Meng Qi,Li-Dong Geng,Quan Xu,Yang Zhou

The in situ mining technology is applied to the exploitation of medium- and low-maturity shale oil, which can use heaters to warm up the oil shale formations and pyrolyze the kerogen. Due to the low thermal conductivity of oil shale, electric heaters need extra equipment to improve heat transfer efficiency. In this study, a thermally conductive proppant is fabricated by coating epoxy-resin and graphite on ceramic proppants for the first time, which could support the fracturing crack and transfer heat. The thermal conduction property of epoxy-resin and graphite coated proppants (EGPs) is 245% higher than that of uncoated proppants, which can transfer more heat to the oil shale formation and accelerate the conversion of kerogen. The adhesive property of EGPs is improved by 47.9% under the load force of 1500 nN, which prolongs the time for the fracture to close. In summary, this novel proppant is expected to assist in-situ mining technology in the production of medium and low-maturity shale oil.

Water-soluble β-cyclodextrin based turn-on amplifying fluorescent probes for sensitive and selective detection of Hg2+/Hg+ ions

Kaiqi Liu,Luminita Marin,Xinjian Cheng

In this work, fluorescent β- cyclodextrin (β-CD) based probes containing naphthalimide group were synthesized to realize the specific recognition of Hg 2+ /Hg + in aqueous system. Firstly, three small fluorescent molecules (N1, N2 and N3) with -NH 2 groups were synthesized from 4-bromo-1, 8-naphthalene anhydride . Secondly, CH CCH 2 - group was introduced into β-CD by Williamson ether formation reaction. Finally, the target probes (β-CD-PI, β-CD-PY and β-CD-TP) were obtained by Amino-Yne click reaction. These probes can efficiently recognize Hg 2+ /Hg + . β-CD-PI emits bright yellow fluorescence after binding with Hg 2+ /Hg + , which is a turn-on fluorescent probe . When the Hg 2+ /Hg + concentration exceeds 26 μM, the fluorescence intensity amplifies sharply (20 folds). The hydrophobic parts of the probes aggregated together to form a micelle-like structure due to complexation with Hg 2+ /Hg + , resulting in special micelle-sensitizing properties. Meanwhile, the HOMO-LUMO energy levels of the probes were calculated by cyclic voltammetry (CV). The probe is expected to be used for the detection of Hg 2+ /Hg + in aqueous solutions without any organic solvents.

The beneficial effects of black phosphorous modification of the anode current collector in Li-metal free Li2S-based batteries

Yun Zhao,Hualin Ye,Huanyu Zhang,Dan Zhao,Limin Huang,Jim Yang Lee

Li–S batteries assembled without a lithium metal anode can significantly increase the battery specific energy and obviate the safety issue of excess Li metal in the battery. In this study we found that a black phosphorous (BP) modified cooper foil current collector could provide a beneficial anode solid-electrolyte-interface (SEI) to enable the charging and discharging of Li-metal free Li 2 S-based batteries at higher C rates. The BP modification is effective in several aspects: the lithiophilicity of BP reduces the energy barrier in Li metal deposition and stripping during battery charge and discharge. The reactions between BP and lithium polysulfides also form Li 7 PS 6 in the anode SEI layer. Since Li 7 PS 6 has a high ionic conductivity for Li  +  diffusion, the Li plating/stripping efficiency is improved. The synergy of the lithiophilicity of BP and a Li 7 PS 6 -rich anode interphase layer was demonstrated in Li-metal free Li 2 S batteries, where the capacity retention over 100 cycles is 64.8% at the 0.2 C rate. The findings here show that current collector modifications should attend to multiple functionalities in order to be effective for the Li-metal free Li 2 S batteries.

Effect of Nitrogen and Sulfur Co-Doped Graphene on the Electrochemical Hydrogen Storage Performance of Co0.9Cu0.1Si Alloy

Fan Wenhao,Zhao Jianxun,Liu Dayong,Liang Qingcheng,Liu Wanqiang,Wang Qingshuang,Liu Heng,Chen Peng,Gao Shang,Bao Xinlong,Cheng Yong,Wang Xinwei,Guo Xin

Co 0.9 Cu 0.1 Si alloy was prepared by mechanical alloying method. Nitrogen-doped graphene (NG) and nitrogen–sulfur co-doped graphene (NSG) were prepared by hydrothermal method. 5 wt% graphene oxide, NG and NSG were doped into Co 0.9 Cu 0.1 Si alloy, respectively, by ball milling to improve the electrochemical hydrogen storage performance of the composite material. X-ray diffraction and scanning electron microscopy were used to characterize the structure and morphology of the composite material, and the LAND battery test system and three-electrode battery system were used to test the electrochemical performance of the composite material. The composite material showed better discharge capacity and better cycle stability than the pristine alloy. In addition, in order to study the optimal ratio of NSG, 3%, 5%, 7% and 10% of NSG were doped into Co 0.9 Cu 0.1 Si alloy, respectively. Co 0.9 Cu 0.1 Si alloy doped with 5% NSG had the best performance among all the samples. The best discharge capacity was 580.1 mAh/g, and its highest capacity retention rate was 64.1%. The improvement in electrochemical hydrogen storage performance can be attributed to two aspects. On the one hand, the electrocatalytic performance of graphene is improved by co-doping nitrogen and sulfur, on the other hand, graphene has excellent electrical conductivity.

Photocatalytically Active Semiconductor Cu3P Unites with Flocculent TiN for Efficient Removal of Sulfamethoxazole

Huancong Shi,Xulei Yao,Shijian Lu,Yuanhui Zuo,Tao Zheng,Liangquan Jia

Sulfamethoxazole is a widely—used antibiotic with high water solubility and low biodegradability, which was considered a refractory environmental pollutant. Hence, a series of functionalized hybrids uniting Cu3P with TiN were prepared. The Cu3P/TiN—x composites remarkably removed the sulfamethoxazole in solution compared with Cu3P and TiN alone. All the as—prepared Cu3P/TiN—x hybrids integrated the advantages of strong adsorption and photocatalysis and achieved removal rates above 70% of sulfamethoxazole. Among the composites, the Cu3P/TiN—2 with a 1:1 molar ratio of Cu: Ti reached a 90% removal rate under dark adsorption for 30 min and subsequent photodegradation for 120 min. The enhanced performance of the Cu3P/TiN—x composites is attributed to the introduced flocculent TiN with a large specific surface area and high conductivity that provide more reactive sites and high electron transferability. Meanwhile, the strong corrosion resistance and chemical stability were also beneficial to the improved performance. Cycling experiments further demonstrate the stability and reliability of the composites. In addition, the capture experiments indicated that the superoxide radical (·O2−) and hydroxyl radical (·OH) played a major role in sulfamethoxazole degradation.Keywords:Cu3P/TiN;plasmonic photocatalyst;sulfamethoxazole;photodegradation

Synthesis of N-(2-ethylhexyl)-pyridine-4-carboxamide and its synergistic behaviors with dinonylnaphthalene sulfonic acid for the selective extraction of nickel and cobalt

Wensen Liu,Hui Su,Jian Zhang,Lina Wang,Yahui Liu,Jie Liang,Zhaowu Zhu

The hydrometallurgical process for the recovery of nickel and cobalt requires a complex and expensive impurity removal process. Solvent extraction is widely used in industry for the separation, purification, and concentration of metals. However, current commercial extractants encounter some difficulties when cobalt and nickel are extracted from solutions containing a large amount of impurities such as manganese and calcium. There is an urgent need to develop new reagents for the selective extraction of Ni and Co. In this study, N-(2-ethylhexyl)-pyridine-4-carboxamide (NEHPCA) was synthesized, and the metal extraction capacity of its synergistic solvent extraction (SSX) system with dinonylnaphthalene sulfonic acid (DNNSA) and tributyl phosphate (TBP) modifier was examined. The experimental results show that the selectivity of the new SSX system has the order Cu > Ni > Co > Zn > Mn > Ca > Al ≈ Cr (III) ≈ Mg ≈ Fe (III), with excellent selectivity for nickel and cobalt. Using an organic phase composed of 0.7 M NEHPCA, 0.35 M DNNSA, and 0.2 M TBP under 1:1O/A operation, after three-stage theoretical extraction, more than 99% of nickel and cobalt can be recovered from a synthetic leaching solution of nickel laterite ore. Mechanistic studies showed that NEHPCA and water molecules participate in the internal coordination of metals, and DNNSA provided coordination anions to achieve charge balance, forming the Ni complex in this SSX system which existed most likely in the form of [Ni(NEHPCA) 2 (H 2 O) 4 ](DNNS) 2 in the organic phase.

Approaching the structure-property relationship of sintered metal nano/microparticles from the perspective of the agglomerate size effect

Guannan Yang,Haiqi Lai,Wei Lin,Jing Tong,Zhen Peng,Jun Cao,Jiye Luo,Yu Zhang,Chengqiang Cui

In this study, we explore the structure-property relationship of sintered metal nano/microparticles from the perspective of the agglomerate size effect. Through sintering experiments and mechanical tests of Cu particle pastes with different solvents, a linear correlation between the agglomerate size in the particle paste ( L a ) and the size of large-scale cavities in the sintered structure ( L c ) is revealed, and a negative correlation between the cavity size and the shear strength of the sintered structure is discovered. Based on these results, a quantitative model is proposed to predict the overall strength of the sintered structure ( τ f ). A relationship τ f = τ c /(1 + √(2 L cmax / d )) is established, which fits the experimental results very well. The model reveals that the relative agglomerate size ( L a / d ) or relative cavity size ( L c / d ) plays a more important role than the particle size ( d ) itself in terms of defining the final sintering properties of metal nano/microparticles.

Integration of ultrafine CuO nanoparticles with two-dimensional MOFs for enhanced electrochemical CO2 reduction to ethylene

Linlin Wang,Xin Li,Leiduan Hao,Song Hong,Alex W. Robertson,Zhenyu Sun

To facilitate the electrochemical CO 2 reduction (ECR) to fuels and valuable chemicals, the development of active, low cost, and selective catalysts is crucial. We report a novel ECR catalyst consisting of CuO nanoparticles with sizes ranging from 1.4 to 3.3 nm anchored on Cu metal-organic framework (Cu-MOF) nanosheets obtained through a one-step facile solvothermal method. The nanocomposites provide multiple sites for efficient ambient ECR, delivering an average C 2 H 4 faradaic efficiency (FE) of ~50.0% at –1.1 V (referred to the reversible hydrogen electrode) in 0.1 mol/L aqueous KHCO 3 using a two-compartment cell, in stark contrast to a C 2 H 4 FE of 25.5% and 37.6% over individual CuO and Cu-MOF respectively, also surpassing most newly reported Cu-based materials under similar cathodic voltages. The C 2 H 4 FE remains at over 45.0% even after 10.0 h of successive polarization. Also, a ~7.0 mA cm −2 C 2 H 4 partial geometric current density and 27.7% half-cell C 2 H 4 power conversion efficiency are achieved. The good electrocatalytic performance can be attributed to the interface between CuO and Cu-MOF, with accessible metallic moieties and the unique two-dimensional structure of the Cu-MOF enhancing the adsorption and activation of CO 2 molecules. This finding offers a simple avenue to upgrading CO 2 to value-added hydrocarbons by rational design of MOF-based composites.

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