ADVANCED MATERIALS
·
2020
·Vol. 33
·期 3
·2006118
·
IF 27.398
Zhengping Ding,Chen Yang,Jian Zou,Shulin Chen,Ke Qu,Xiumei Ma,Jingmin Zhang,Jing Lu,Weifeng Wei,Peng Gao,Liping Wang
Fluorographites (CF x ) are ultrahigh-energy-density cathode materials for alkaline-metal primary batteries. However, they are generally not rechargeable. To elucidate the reaction mechanism of CF x cathodes, in situ transmission electron microscopy characterizations and ab initio calculations are employed. It is found that it is a two-phase mechanism upon K/Na/Li ion insertion; crystalline KF (crystalline NaF nanoparticles and amorphous LiF) is generated uniformly within the amorphous carbon matrix, retaining an unchanged volume during the discharge process. The diffusivity for K/Na/Li ion migration within the CF x is ≈2.2–2.5 × 10 –12 , 3.4–5.3 × 10 –12 , and 1.8–2.5 × 10 –11 cm 2 s –1 , respectively, which is comparable to the diffusivity of K/Na/Li ions in liquid-state cells. Encouraged by the in situ transmission electron microscopy (TEM) results, a new rechargeable all-solid-state Li/CF x battery is further designed that shows a part of the reversible specific discharge capacity at the 2nd cycle. These findings demonstrate that a solid-state electrolyte provides a different reaction process compared with a conventional liquid electrolyte, and enables CF x to be partly rechargeable in solid-state Li batteries.
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PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
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2020
·Vol. 217
·期 8
·1900806
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IF 1.759
Jingbo Li,Yu Liu,Fang Xu,Junping Hu,Nan Chen,Guoping Du,Changshuang Jiang
As a 2D material, Ti 3 C 2 (MXene) has been recently used as electrodes for electrochemical capacitors. Herein, a two-step procedure is used to obtain a highly opened layer structure for Ti 3 C 2 , which differs from the methods used in the literature for synthesizing exfoliated MXene. First, the mild NH 4 HF 2 etching agent is used to prepare the regular Ti 3 C 2 MXene. Second, KOH is added into the obtained solution for K + to intercalate the MXene. The K + intercalation is found to greatly increase the (002) crystal planar spacing of the Ti 3 C 2 from 10.8 to 12.4 Å. More importantly, this K + -intercalated MXene exhibits a highly opened layer structure, whereas the regular MXene only has a partially opened layer structure. Consequently, the former is expected to allow much more active sites exposed to liquid electrolyte, and also facilitates remarkably higher ion and electron transport efficiency. To investigate their electrochemical capacitance properties, the regular and K + -intercalated Ti 3 C 2 MXenes are used to fabricate binder-free electrodes on nickel foams by an electrophoretic deposition method. The K + -intercalated MXene-based electrode is found to have twice higher specific capacitance than the regular MXene. Furthermore, the K + -intercalated Ti 3 C 2 MXene-based electrode exhibits an excellent cyclic stability.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2021
·
IF 5.455
Ying Shi,Qiuming Zhou,Zhangfeng Qin,Zhiwei Wu,Weiyong Jiao,Mei Dong,Weibin Fan,Jianguo Wang
The aromatization of alkanes is an important process for improving the quality of Fischer-Tropsch synthesis (FTS) gasoline and producing high-valued aromatics from naphtha ; however, currently available catalysts in this regard are often deficient due to the low aromatics yield and short lifetime. In this work, a series of hierarchically structured Beta (Beta-HS) zeolites with high crystallinity and meso-porosity were synthesized by steam treatment with various organosilanes as pore-forming reagent and ethanol as solvent. The nano-sized Beta-HS zeolites were further modified with K through ion-exchange and with Pt through incipient wetness impregnation; the resultant Pt/K-Beta-HS catalysts were then used in the aromatization of n -heptane. The results indicate that the abundant mesopores present in Beta-HS are conducive to the diffusion of reactants and products, whilst the modification with K is able to passivate the strong Brønsted acid sites and the loading of Pt metal can promote the dehydrogenation of alkanes and cycloalkanes, which can effectively suppress the cracking and carbonaceous deposition reactions and enhance the dehydrogenation aromatization activity. As a result, the Pt/K-Beta-HS catalysts exhibit excellent performance in the aromatization of n -heptane, with a much longer lifetime (205 h), higher selectivity to aromatics (80%) and larger turnover number of aromatic products (Pt-based TON, 240 × 10 3 ) than conventional Beta zeolites. These results prove that the steam treatment with organosilanes as pore-forming reagent is a facile and cost-effective strategy to synthesize the hierarchically structured Beta zeolites and after loading K and Pt, the Pt/K-Beta-HS zeolites can be an efficient catalyst for the conversion of n -heptane to aromatics.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 105
·期 1
·461-468
·
IF 3.784
Baoyu Deng,Yiming Ma,Tianxiang Chen,Huajing Wang,Jinfeng Lin,Cong Lin,Xiao Wu,Chunlin Zhao,Tengfei Lin,Min Gao,Xinghua Zheng,Changqing Fang
Dense (K, Na)NbO 3 ceramics are successfully fabricated via the cold sintering process at 350°C under a uniaxial pressure of 400 MPa for 4 h. Equimolar KOH and NaOH solutions were utilized as a transient alkaline flux. The microstructure and dielectric properties were studied in detail. Scanning electron microscope and the relative densities reveal dense structures of the ceramics. After post-annealing at 800°C for 1 h, the ceramics show good electrical performance. The relative dielectric permittivity is 829 (at 10 kHz) at room temperature, and the piezoelectric constant ( d 33 ) reaches up to 148 pC/N. The cold sintering technique with equimolar KOH and NaOH solutions as a transient alkaline flux endow KNN ceramics with excellent dielectric and piezoelectric properties, showing a potential way to fabricating other KNN-based ceramics at low temperature.
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CARBON
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2021
·
IF 9.594
Xiang Gao,Wei Liu,Tianqi Wang,Jingrou Dai,Yuanyuan Pan,Yongxu Du,Yongpeng Cui,Hongguang Fan,Shuang Liu,Yongcheng Jin
N-doping can endow carbon materials with high electrochemical activity. Besides the widely validated sp 2 -hybridized nitrogen doping, sp -hybridized nitrogen ( sp - N ) atoms are also expected to be new active sites. However, both sp - N atoms and cyano (CN) groups containing sp - N are rarely produced in carbon materials presently. In this work, the first cyano groups-modified carbon materials are synthesized firstly via an interesting struggle between the chemical etching of KOH and the catalytic graphitization of Co nanoparticles in carbon frameworks. The theoretical calculations and experimental results manifest that the stronger electronegativity of CN groups renders carbon materials a higher electrochemical activity. As K + storage anodes, the CN − modified carbon materials exhibit an obvious boost in potassium storage performance in both ester- and ether-based electrolytes. Therefore, as a new N doping form, the successful introduction of CN groups into carbon materials opens a door for exploring sp -N doped carbon materials for applications in energy storage and other fields.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2019
·
IF 2.298
Chao Ye,Zhong-Zhong Wu,Shi-Hua Sang,Xiao-Yun Qi,Xing Liu
The solid–liquid phase equilibria of the ternary system KBr–LiBr–H2O at 273 and 308 K were determined by the isothermal dissolution equilibrium method. On the basis of the obtained experimental data, the stable phase diagrams of ternary system KBr–LiBr–H2O at 273 and 308 K were plotted, respectively. The results show that the ternary system is a simple cosaturated type at two different temperatures, and there is neither a solid solution nor a double salt in the system. Both of the phase diagrams include one invariant point, two univariant curves, and two crystalline regions (where the solids are LiBr·2H2O and KBr, respectively). The crystalline area of KBr is much larger than that of LiBr·2H2O, indicating that the solubility of KBr is much smaller than that of LiBr in the ternary system. The mass fraction of KBr in the equilibrium liquid phase is obviously reduced, which indicates that LiBr has a strong salting-out effect on KBr.
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MACROMOLECULES
·
2019
·
IF 5.997
Chao Qian,Runxin Bei,Tianwen Zhu,Weiwen Zheng,Siwei Liu,Zhenguo Chi,Matthew. P. Aldred,Xudong Chen,Yi Zhang,Jiarui Xu
An original design strategy for the preparation of polymers with a low dielectric constant is presented. The key to this design strategy is taking the most advantage of the secondary relaxation behavior of the polymer chains to obtain more free volume in the bulk, which can effectively reduce the dielectric constant of the polymer. By using this design strategy, we have successfully synthesized a novel polyimide TmBPHF with a pendant group that consists of a biphenyl unit attached to the meta-position of a phenyl ring that is part of a triaryl unit. The intrinsic k and dielectric loss values of the TmBPHF are 2.09 and 0.0012 at 10 kHz, respectively. More importantly, such outstanding low-k performance remains stable up to 300 °C. The excellent low-k performance of TmBPHF is mainly due to the secondary relaxation, especially the β relaxation, which occurs from the rotation of the pendant group. The TmBPHF film shows an ultralow moisture rate (∼0.17%), which is able to maintain the low-k property stability in different humid environments. Meanwhile, the TmBPHF film also shows excellent thermal stability and excellent mechanical properties, with a glass transition temperature (Tg) of 302 °C, 5 wt % decomposition temperature (Td5%) of 549 °C, and residual of 70% at 800 °C under N2. The tensile strength and tensile modulus of the polyimide film are equal to 85.8 MPa and 2.02 GPa, respectively. In addition, the TmBPHF film is soluble in common solvents, which allows simple solution processing and efficient, low-cost, and continuous roll-to-roll processes. The design strategy is beneficial for lowering the k value and simultaneously maintaining the overall properties of polyimides, which possibly could also be extended to other novel high-performance polymer systems.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Maruthupandy Muthuchamy,Rajivgandhi Govindan,Kadaikunnan Shine,Veeramani Thangasamy,Naiyf S. Alharbi,Muneeswaran Thillaichidambaram,Jamal M. Khaled,Jun-Li Wen,Khalid F. Alanzi
In this study graphene/chitosan nanoparticles (GR/CS NCs) were developed. The homogenous combination of GR and CS was confirmed by FTIR spectroscopy. The combination of CS with GR sheets reduced the XRD intensity of the GR peak in GR/CS NCs, while TEM images revealed the immobile CS coating of GR sheets. Further, the anti-biofilm activity of GR/CS NCs was tested. The tests showed that the formation of biofilm by Pseudomonas aeruginosa and Klebsiella pneumoniae was inhibited at 40□g/mL GR/CS NCs up to 94 and 92 %, respectively. The intracellular and cell surface damage of the bacteria was observed by CLSM and SEM. Also, GR/CS NCs produced a toxic effect of 90 % on Artemia franciscana at 70□g/mL upon 24 h incubation. The recorded properties of the synthesized GR/CS NCs qualify them as potential agents against multi-drug resistant bacteria.
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JOURNAL OF MOLECULAR LIQUIDS
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2012
·
IF 1.58
Mengyin Hou,Yingjie Xu,Yajuan Han,Bin Chen,Wenxia Zhang,Qinghua Ye,Jinzhi Sun
Densities ( ρ ), refractive indices ( n D ) and electrical conductivities ( κ ) of ethylammonium acetate (N2Ac) protic ionic liquid + water and propylammonium acetate (N3Ac) protic ionic liquid + water binary mixtures over the entire composition range were measured at 298.15 K under atmospheric pressure. The excess molar volumes ( V E ), apparent molar volumes ( V ϕi ), partial molar volumes ( V ¯ m , i ) and excess partial molar volumes ( V ¯ m , i E ) of the binary mixtures were calculated from the density data. The refractive index deviations (Δ n D ) of the binary mixtures were determined using the refractive index data. The excess molar volumes and refractive index deviations were correlated with the Redlich–Kister equation. The excess molar volumes of the above-mentioned systems are negative over the whole composition range, while the refractive index deviations are positive. The concentration dependence of electrical conductivity was fitted according to the empirical Casteel–Amis equation. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties.
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TALANTA
·
2015
·
IF 3.545
Shenguang Ge,Lina Zhang,Yan Zhang,Haiyun Liu,Jiadong Huang,Mei Yan,Jinghua Yu
A low-cost, simple, portable and sensitive paper-based electrochemical sensor was established for the detection of K-562 cell in point-of-care testing. The hybrid material of 3D Au nanoparticles/graphene (3D Au NPs/GN) with high specific surface area and ionic liquid (IL) with widened electrochemical windows improved the good biocompatibility and high conductivity was modified on paper working electrode (PWE) by the classic assembly method and then employed as the sensing surface. IL could not only enhance the electron transfer ability but also provide sensing recognition interface for the conjugation of Con A with cells, with the cell capture efficiency and the sensitivity of biosensor strengthened simultaneously. Concanavalin A (Con A) immobilization matrix was used to capture cells. As proof-of-concept, the paper-based electrochemical sensor for the detection of K-562 cells was developed. With such sandwich-type assay format, K-562 cells as model cells were captured on the surface of Con A/IL/3D AuNPs@GN/PWE. Con A-labeled dendritic PdAg NPs were captured on the surface of K-562 cells. Such dendritic PdAg NPs worked as catalysts promoting the oxidation of thionine (TH) by H 2 O 2 which was released from K-562 cells via the stimulation of phorbol 12-myristate-13-acetate (PMA). Therefore, the current signal response was dependent on the amount of PdAg NPs and the concentration of H 2 O 2 , the latter of which corresponded with the releasing amount from cells. So, the detection method of K-562 cell was also developed. Under optimized experimental conditions, 1.5×10 −14 mol of H 2 O 2 releasing from each cell was calculated. The linear range and the detection limit for K-562 cells were determined to be 1.0×10 3 –5.0×10 6 cells/mL and 200 cells/mL, respectively. Such as-prepared sensor showed excellent analytical performance with good fabrication reproducibility, acceptable precision and satisfied accuracy, providing a novel protocol in point-of-care testing of cells.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2013
·
IF 2.004
Fuqiong Lei,Qinbo Wang,Xing Gong,Binwei Shen,Bingyan Mao,Xiang Ye
Liquid–liquid equilibrium (LLE) data for the ternary system water + cyclohexane + acetic acid have been measured at (303.2 to 333.2) K under atmospheric pressure. The Othmer–Tobias and Bachman equations were used to check the reliability of the obtained tie-line data. The experimental data were correlated by NRTL (nonrandom two-liquid) activity coefficient model, and the relevant interaction parameters were regressed with the experimental data. The predicted values by NRTL method show good consistency with the measured data. The obtained interaction parameters can be used in the calculation of LLE for the ternary system water + cyclohexane + acetic acid as well as for the design and optimization of the related separation process.
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JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Hengde Li,Zhangni Feng,Li Wan,Cheng Huang,Tianfei Zhang,Yanxiong Fang
As an eco-friendly compound from essential oils, 1,8-cineole (cineole, eucalyptol) has the potential to replace the ozone depleting industrial solvents. This paper presents experimental (liquid + liquid) equilibrium (LLE) data for four alcohol–water systems containing 1,8-cineole. To evaluate the phase equilibrium properties of 1,8-cineole in aqueous alcohol mixtures, LLE values for the ternary systems (water + methanol or ethanol or 1-propanol or 1-butanol + 1,8-cineole) were determined with a tie-line method at T = 298.15 K under atmospheric pressure. The well-known Hand, Bachman and Othmer–Tobias equations were used to test the reliability of the experimental results. The binodal curves and distribution ratios of alcohol in the mixtures are shown and discussed. The experimental LLE values were satisfactorily correlated by the NRTL and UNIQUAC models.
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危险品化学品经营许可证（带存储）