Table of Content

10 February 2023, Volume 44 Issue 2

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Content

Cover and Content of Chemical Journal of Chinese Universities Vol.44 No.2(2023)

2023, 44(2):  1-6. 

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Review

Self-assembly of Cellulose Nanocrystals in Spatial Confinement： from Colloidal Liquid Crystals to Functional Materials

DUAN Yixiong, YANG Bai, LI Yunfeng

2023, 44(2):  20220474.  doi:10.7503/cjcu20220474

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Cellulose nanocrystals（CNCs）， as one of the most promising bioderived materials， have many important applications in the fields of energy， biomedicine and photonic materials because of their abundance， biocompatibility， and ability to form photonic structures. This perspective highlights the recent advances in the self-assembly of CNCs in spatially confined geometry. We review the preparation of CNCs， the cholesteric liquid crystal formed by CNCs， photonic materials derived from CNCs， self-assembly of CNCs in the droplets and cylindrical capillary and functional materials based on the confined assembly of CNCs， and discuss the new research directions in the self- assembly of CNCs in spatial confinement.



Article: Inorganic Chemistry

Effect of Aluminium Nanopowders on Activation of Dendritic Cells

ZHU Ge, LI Zhihan, LIU Kun, SUN Tianmeng

2023, 44(2):  20220602.  doi:10.7503/cjcu20220602

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Aluminum nanopowders（ALEX） were prepared by electrical explosion and their effects of immune enhancing and tumor prevention were verified. The ALEX with well-dispersion were synthesized by electrical explosion of wires method， combing with carboxyl group polymer ligand reaction. The antigenic protein ovalbumin（OVA） and peptide was grafted onto ALEX surface by physical electrostatic adsorption. Fourier transform infrared spectroscopy demonstrated the grafting of antigen to ALEX. The immune enhancing effect of ALEX was verified： in vitro experiments showed that ALEX could improve the antigen presentation function of dendritic cells and the quantitative detection of antibodies in the serum of mice after immunization showed that ALEX could significantly increase the titer of antigen-specific antibodies. Finally， the tumor vaccine containing ALEX was proved to be effective for tumor prevention using mouse melanoma model.



Analytical Chemistry

High-throughput Biological Microarrays Based on Framework Nucleic Acids

SONG Lu, ZHANG Shuyang, WANG Lihua, ZUO Xiaolei, LI Min

2023, 44(2):  20220563.  doi:10.7503/cjcu20220563

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A high-throughput biological microarray based on framework nucleic acid（FNA） was constructed. Using an automated ultra-micro pipetting platform， the droplets containing FNAs-based probes were fabricated onto the glass substrates according to the pre-defined commands. After the targets were captured by the probes， the micro- arrays were scanned by the integrated gene chip scanner， the results of which could be further used for the quantifi- cation of target concentration. It was found that the FNA probes could be prepared with high throughput on the bio- logical microarrays， and the microarrays with 150000 spots can be prepared within 24 h. Moreover， the relative deviation（W） of distance between the points is less than 10%， and the coefficient of variation（CV） of fluorescence intensity is 3.30%. The properties of each spot on the microarrays were stable， which is much higher than the national standard. Additionally， we demonstrated that the FNA-based microarray possessed high addressability， high sen- sitivity and high-throughput capabilities. The limit of detection for nucleic acid target was down to 100 pmol/L. With the progress of various probe technologies， the microarray platform shows great potential for bioanalysis.



Conjugate Size and Surface Oxidation Synergistically Trigger Red Fluorescence in Carbon Dots for Detecting Trace Water in Organic Solvents

FU Fangmei, XU Mengru, LIANG Zishan, HUANG Sirui, LI Hui, ZHANG Haoran, LI Wei, ZHENG Mingtao, LEI Bingfu

2023, 44(2):  20220464.  doi:10.7503/cjcu20220464

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In this paper， o-phenylenediamine and dopamine hydrochloride were used as precursors， and the pH values of the reaction system（pH=7， 3， 1） were adjusted by phosphoric acid to obtain carbon dots（CDs） with gradually red-shifted fluorescence， namely CDs-7（green）， CDs-3（orange） and CDs-1（red）， respectively. Trans-mission electron microscopy（TEM）， Raman spectroscopy（Raman）， Fourier transform infrared spectroscopy （FTIR）， X-ray electron spectroscopy（XPS）， UV-Vis absorption spectrum and fluorescence lifetime decay curves analysis demonstrated that the decrease of the reaction system pH promoted the precursor carbonization and cross-linking， which led to the increase of sp² conjugate domain size and graphitization， resulting in the fluorescence red-shift of CDs. In addition， the acidic environment favors the formation of carboxyl groups by oxidation on the surface of CDs， which further promotes the red-shift of CDs fluorescence while improving the quantum efficiency（QY）. Finally， because of its high QY（14.8%） and solvent-dependent luminescence， CDs-1 was used as a fluorescent probe to detect trace water in ethyl alcohol（EtOH）， N，N-dimethylformamide（DMF） and 1，4-dioxane（DIO）， with detection limits of 0.86%， 0.123% and 0.023% respectively. It is proved that CDs-1 has great potential in the detection of trace water.



Organic Chemistry

Dominoes Type Reaction of Spatially Close Diamides and Their Applications in Organic Synthesis

ZHANG Jialing, WU Yuanyuan, ZHANG Man, TAO Zhengyu, TIAN Yongpan, ZHANG Qianfeng, TONG Bihai, HE Gufeng, KONG Hui

2023, 44(2):  20220597.  doi:10.7503/cjcu20220597

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A monoaddition reaction of spatially close diamides and Grignard reagents under mild conditions was found. In some case， kinetic-controlled products and thermodynamic-controlled products were obtained at the same time. The key step involved an intramolecular nucleophilic reaction. 4-Substituted phthalazinones were conveniently synthesized by this method. Pure red-light-emitting tris-cyclometalated iridium（Ⅲ） complex based on phthalazine building blocks that exhibit high efficiency［maximum external quantum efficiency（EQE_max）=10.3%］ had also been synthesized.



Palladium Catalyzed Selective Synthesis of Pyrrolofuran Derivatives and Carbamates from Propargylic Alcohols and tert⁃Butyl Isonitrile

LIN Junxu, XI Zhiwei, LI Zhiping, WANG Yingchun

2023, 44(2):  20220473.  doi:10.7503/cjcu20220473

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Palladium catalyzed highly selective synthesis of pyrrolofuran derivatives and carbamates from propargy⁃lic alcohols and tert-butyl isonitrile was described. In the presence of 10%（molar fraction） Pd（OAc）₂ and 110% （molar fraction） LiBr， an “orderly” isonitrile triple insertion reaction occurred between one molecule of propargylic alcohols and three molecules of tert-butyl isonitrile with the participation of water， and pyrrolofuran derivatives were selectively obtained in 56%—73% yields. Whereas in the presence of 10%（molar fraction） Pd（PPh₃）₄ and 110%（molar fraction） K₃PO₄， carbamates were exclusively produced in 51%—74% yields via oxidative coupling reaction between a molecule of propargylic alcohols and a molecule of tert-butyl isonitrile with the participation of air（O₂）. Different products with high selectivity could be obtained by simply changing different kinds of palladium catalyst and salt， and this method provides an attractive synthesis route toward pyrrolofuran derivatives and carbamates， respectively.



Physical Chemistry

Theoretical Prediction on the Catalytic Effect of Selenium-deficient WSe₂ in Lithium-sulfur Batteries

HU Pingao, ZHANG Qi, ZHANG Huiru

2023, 44(2):  20220595.  doi:10.7503/cjcu20220595

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Due to the excellent electrical conductivity， high specific surface area and large interlayer spacing， WSe₂ has been used as catalytic material to effectively improve the electrochemical performance of lithium sulfur batteries. However， the active sites are concentrated at the few edges， which hinders the further improvement of catalytic activity. Manufacturing surface defects can expose more surface active sites and improve catalytic activity. Herein， theoretical study was carried out on the polysulfide adsorption， lithium ion migration and polysulfide conversion of selenium-deficient WSe₂ with different vacancy concentrations（3.125%， 6.25%， 9.375% and 12.5%）， to explore the application potential of Se-deficient WSe₂ in Li-S batteries. It is revealed that medium vacancy concentration WSe₂（6.25%） has moderate polysulfide adsorption capacity， rapid lithium ion migration and synchronous promotion to charge and discharge process， which is the most advantageous surface. In comparison， the low vacancy（3.125%） defect surface is unfavorable to polysulfide adsorption， lithium ion migration and charge-discharge process. For the high vacancy defect surface（9.375% and 12.5%）， although it is conducive to the lithium migration， it has too strong short chain polysulfides adsorption and unfavorable discharge process. The results provide theoretical guidance for the application of defective tungsten selenide in lithium sulfur battery.



Preparation and Application of a Novel Porphyrin-based Porous Organic Polymer COP-180 Supported Palladium Catalyst

HE Jianyun, JIANG Yunbo, ZHANG Aimin, TANG Zhenyan, LI Hongpeng

2023, 44(2):  20220535.  doi:10.7503/cjcu20220535

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5，10，15，20-Tetra（4-nitrophenyl）-21H，23H porphyrin（TNPPH₂） was synthesized by condensation reaction with p-nitrobenzaldehyde， acetic anhydride and pyrrole as raw materials and propionic acid as solvent. The porphyrin-based porous organic polymer COP-180 was synthesized with TNPPH₂ and p-phenylenediamine as raw materials and anhydrous N，N'-dimethylformamide（DMF） as solvent. Then the catalyst Pd@COP-180 was prepared by impregnation method without reducing agent with COP-180 as carrier and chloroparadic acid as precursor. The structures of the support and catalyst were characterized by Fourier transform infrared spectroscopy（FTIR）， differential scanning calorimetry-thermogravimetric analysis（DSC-TG）， transmission electron microscopy（TEM）， X-ray photoelectron spectroscopy（XPS） and N₂ adsorption desorption. Finally， the Suzuki-Miyaura cross-coupling reaction and 4-nitrophenol（4-NP） hydrogenation reduction reaction were used as model reactions to test the catalytic performance of catalyst； 0.5%（molar fraction） catalyst shows high efficiency in Suzuki coupling reaction of iodobenzene and phenylboric acid as substrate， and it has been used 10 times， there is still a high yield. When the amount of catalyst was 0.01%（molar fraction）， the turn over frequency（TOF） was up to nearly 10000 h^‒1. At room temperature， 20.46 μg 4-NP can be completely reduced by 8.00 μg catalyst in 10 minutes， and the standardized activity parameter k_n was 894.60 s^‒1·g^‒1Pd.



Preparation of Mesoporous Silica Supported Highly Dispersed Vanadium Catalyst and Their Catalytic Performance for Selective Oxidation of Ethane

SONG Jiaxin, CUI Jing, FAN Xiaoqiang, KONG Lian, XIAO Xia, XIE Zean, ZHAO Zhen

2023, 44(2):  20220532.  doi:10.7503/cjcu20220532

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A series of mesoporous silica supported vanadium catalysts was prepared by incipient-wetness impregnation method using porous silica with high specific surface area as support. And the catalytic performances were tested for the selective oxidation of ethane. The catalysts were characterized by X-ray diffraction（XRD）， ultraviolet-visible diffuse reflectance spectrum（UV-Vis DRS） and H₂-temperature programmed reduction（H₂-TPR）. The effects of vanadium loadings on the structure of the catalyst were investigated. It was found that the vanadium species on the surface of the catalysts changed from highly dispersed oligomeric VO _x to highly polymerized VO _x with the increase of vanadium loading. The highly dispersed vanadium species can improve the selectivity of ethene and acetaldehyde.



Electrochemical Impedance Spectroscopy and Kinetics of Chloride Ion Removal by Electroadsorption

SUN Zhumei, FU Jie, LI Xin, WANG Haifang, LU Jing, TONG Tianxing, ZHU Mingfei, SHU Yude, WANG Yunyan

2023, 44(2):  20220528.  doi:10.7503/cjcu20220528

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The dynamics of electroadsorption faces the problem of large experimental workload， and can’t directly reveal the rate control steps. In this study， a method to determine the relaxation time of Cl^- adsorbed on activated carbon was proposed based on electrochemical impedance spectroscopy. The speed control step was determined according to the relaxation time. The effects of anode potential， pretreatment time and pretreatment concentration on the electrochemical process were studied. Based on the obtained electrochemical impedance spectroscopy， the relaxation time and coverage of electroadsorbed Cl^- under different conditions were obtained. The results show that the Nyquist plots obtained under different conditions are composed of a capacitive reactance arc and an inductive reactance arc， which represent the charge transfer process of Cl^- on the anode and the adsorption process of Cl^- on the activated carbon electrode， respectively. The relaxation time can be effectively shortened by anode polarization. When the anode polarization is applied， the relaxation time is 2.0×10^-5 s. With the increase of pretreatment time， the relaxation time gradually increases. When the pretreatment time is 180 min， the relaxation time increases to 4.9×10^-5 s. The effect of pretreatment concentration on relaxation time is negligible. The relaxation time shows that the adsorption rate of Cl^- is slower than the diffusion rate， and adsorption is the speed control step of the electroadsorption process. The electrode surface coverage is low， only 10^-4 orders of magnitude. This method is more accurate and intuitive than the kinetic model fitting to determine the control steps， and provides a theoretical and methodological basis for the study of electroadsorption process dynamics.



Law and Mechanism of Enrichment of Baicalin in Scutellaria baicalensis by Cu-NIC-TMED

GUO Wenjuan, ZHANG Ying, YU Jie, DAI Zhao, HOU Weizhao

2023, 44(2):  20220511.  doi:10.7503/cjcu20220511

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In this paper， nicotinic acid was used as the ligand to prepare copper nicotinate coordination polymer， and the metal organic framework（MOFs） material was used for the adsorption， separation and purification of baicalin in Scutellaria baicalensis， and a non-toxic， environmentally friendly， simple process， and efficient extraction method was obtained. In this experiment， the copper nicotinate coordination polymer Cu-NIC-TMED was synthesized by solvothermal method， and then its structure was characterized for proper coordination and accurately synthesized. The law and mechanism of the adsorption of baicalin by Cu-NIC-TMED were studied： the adsorption conformed to the Quasi-secondary kinetic equations， and the equilibrium adsorption data conformed to the Langmuir adsorption isothermal model. At the same time， the optimal adsorption parameters were obtained by optimizing the response surface（RSM）. Under the condition of obtaining the optimal adsorption parameters， the adsorption rate of Cu-NIC-TMED on baicalin in S. baicalensis was as high as 84.08%， and the adsorption effect on other ingredients in S. baicalensis was minimal. Using pH=6.8 phosphate buffered saline（PBS） as the desorption solution， the ratio of Cu-NIC-TMED desorbed baicalin was 41.24%， and the purity of baicalin was increased from 21.55% before adsorption to 75.77% after desorption， Cu-NIC-TMED had good stability before and after adsorption， and the recovery rate reached 78.64%. Therefore， Cu-NIC-TMED has application value in the adsorption and purification of baicalin.



5Ni-5La/SiO₂ Catalysts Prepared by Dielectric Barrier Discharge Plasma Applying in the Dry Reforming of Methane

WANG Yazhi, JIA Xianzhi, ZHANG Honggang, LIU Lu, ZHAO Binran

2023, 44(2):  20220503.  doi:10.7503/cjcu20220503

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Ni-La catalysts were prepared using dielectric barrier discharge plasma method and applied in the dry reforming of methane. CH₄ conversion and CO₂ conversion for the plasma-treated catalysts were 81.2% and 88.4%， respectively， and the catalyst remained stable within 30 h. While for conventional catalyst， the initial conversion rates of CH₄ and CO₂ were 81% and 88.4%， respectively， which finally decreased to 58.8% and 68.6% after 30 h. Thus， the stability of the catalyst prepared by the plasma method was significantly improved. The characterization results showed that the catalyst prepared by dielectric barrier discharge plasma has higher dispersion and stronger Ni-La₂O₃ interaction. The plasma treatment increased the electron density around Ni， which could enhance the adsorption and activation of CO₂ on the surface of the catalyst， promote the formation of HCOO^- intermediates， and facilitate the positive progress of the reaction.



Interaction Mechanism of the Natural Product Falcarindiol and Human GABA_A Receptor

SHEN Qi, CHEN Haiyao, GAO Denghui, ZHAO Xi, NA Risong, LIU Jia, HUANG Xuri

2023, 44(2):  20220500.  doi:10.7503/cjcu20220500

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Falcarindiol is a natural polyacetylene alcohol compound that has demonstrated anti-inflammatory， neurological and potentially anticancer properties， and modulates the activity of the γ-aminobutyric acid type A（GABA_A） receptor which is an important therapeutic target for neurological disorders in humans， but the mechanism of action is not clear. In this paper， the binding mode and dynamic properties of falcarindiol acting on GABA_A receptor were investigated by molecular dynamics simulation， umbrella sampling simulations， binding free energy calculations and molecular docking， and determined that all three effective binding sites have antagonistic effects on this receptor. This work will provide a theoretical basis for the subsequent study of the effects of polyethynyl alcohol analogues on GABA_A receptors and the corresponding drug development.



Preparation of Hierarchical Porous Carbon Materials Using Cellulose Nanocrystals as Templates and Their Electrochemical Properties

WANG Pengfei, FU Wenhao, SUN Shaoni, CAO Xuefei, YUAN Tongqi

2023, 44(2):  20220497.  doi:10.7503/cjcu20220497

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Cellulose nanocrystals（CNC）， phenolic resins， and KOH were used as templates， carbon sources， and activator， respectively， to prepare hierarchically porous carbon materials by high-temperature carbonization. The needle shaped CNC used was 20—40 nm wide and 200—500 nm long， and the carbon residue rate of which at 800 ℃ was only 5.18%（mass fraction）. The as prepared carbon materials were characterized by transmission electron microscopy（TEM）， scanning electron microscopy（SEM）， X-ray photoelectron spectra（XPS）， etc. The results showed that the degradation of CNC in the precursor could form mesopores comparable to diameter of CNC in carbon materials， and KOH activation could result in a large number of micropores and macropores， as well as some smaller mesopores around 4 nm， leading to a typical hierarchical porous structure of the carbon materials. The presence of these pores is beneficial to shorten the electrolyte diffusion path and change the diffusion process of the electrolyte in the internal cavities of the material. The XPS spectra showed that the surface of the carbon material was rich in oxygen-containing functional groups， which help to improve the wetting ability of the carbon material surface in the electrolyte. The specific surface area and total pore volume of the carbon materials prepared using CNC as template and KOH as activator reached 554.7 m ²/g and 0.323 cm ³/g， respectively. This carbon material was further used as the electrode material， the specific capacitance of which could reach 202.8 F/g at a current density of 1.0 A/g， and the capacitance retention rate still reached 69% when the current density increased from 1.0 A/g to 40.0 A/g， indicating the excellent rate performance of the prepared carbon material. The electrode material was further assembled into a supercapacitor. After 10000 charge and discharge cycles， the capacitance retention rate of the supercapacitor was still over 95%， suggesting its good cycle stability. This study showed that using CNC as template can introduce specific-scale mesopores into carbon materials， thereby improving their electrochemical performance， which provide a new method for the preparation of hierarchically porous carbon materials.



Theoretical Calculation of Solvent Dependence in Pd-catalyzed Hydrogenation of Furfural

DENG Yuan, WANG Si, FENG Haisong, ZHANG Xin

2023, 44(2):  20220486.  doi:10.7503/cjcu20220486

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The catalytic hydrogenation reaction process of furfural is mainly divided into gas phase， liquid phase and catalytic transfer hydrogenation. Compared with gas-phase hydrogenation of furfural， liquid-phase hydrogenation provides more sustainability and freedom for the reaction， but the mechanism of the solvent-dependent phenomenon on the directional catalytic conversion of furfural is still unclear. For the above problems， this work selected three solvents（methanol， water and cyclohexane） as the research objects， and used the density functional theory method to explore the effect of solvent on the reactivity and selectivity of Pd-catalyzed furfural hydrogenation. The results showed that the solvent could form hydrogen bond network to promote proton shuttle， stabilize reactants， interme- diates and products， and effectively reduce the energy barrier of C=O hydrogenation. Free energy calculations show that the energy barrier for the first step C=O hydrogenation gradually decreases（0.70 eV>0.68 eV>0.44 eV） with decreasing solvent polarity（water>methanol>cyclohexane）. During the hydrogenation of furfural mediated by water and methanol， the reaction barriers for the first C=O hydrogenation were further reduced to 0.47 and 0.41 eV. Differential charge density and Bader charge analysis indicated the existence of charge transfer between furfural and Pd catalysts. The projected density of states（PDOS） analysis showed that the addition of the solvent shifted the center of the d-band toward the Fermi level， implying the improved catalytic activity of the Pd catalyst. This work reveals the key role of solvent in regulating the selectivity of furfural catalytic hydrogenation.



Modification Mechanism of Mannitol for Preparation of Highly Active Nano-zerovalent Iron

HE Yuting, NIU Huibin, ZHANG Zhaonian, ZHANG Jing, FU Guirong, CHEN Chuncheng, HUANG Yingping, FANG Yanfen

2023, 44(2):  20220470.  doi:10.7503/cjcu20220470

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Nano zero-valent Iron（nZVI） has been widely used in water pollution treatment. The preparation method of nZVI with high purity and good dispersion has always been a research focus. In this paper， alcohols with different numbers of hydroxyl groups were used as modifiers， including ethanol， ethylene glycol， erythritol， mannitol and sorbitol， to prepare nZVI-EA， nZVI-EG， nZVI-ER， nZVI-M and nZVI-S sample， respectively. The above samples were applied to the reduction and removal of microcystin（Microcystin-LR， MC-LR） in water. The results showed that with the increase of hydroxyl groups， the antioxidant capacity and dispersity of modified nZVI were enhanced， and the degradation rate of MC-LR was also increased. The surface-area-normalized rate coefficient of nZVI-M（79.35×10^-5 L·m^‒2·min^‒1） was 9.3 times that of nZVI-S（8.55×10^-5 L·m^‒2·min^‒1） and 61.0 times that of nZVI₀（unmodified sample， 1.30×10^-5 L·m^‒2·min^‒1）. It was found by X-ray diffraction（XRD）， energy dispersive spectroscopy（EDS） and potassium dichromate titration that this may be due to the highest Fe⁰ purity of nZVI-M（total iron content is 83.5%）. In order to reveal the modification mechanism， the preparation process of nZVI-M was observed by optical microscope. It was found that transparent rod-like mannitol crystal clusters formed on the surface of Fe⁰， which improved the antioxidant capacity and dispersion of nZVI in water， and realized the efficient degradation of MC-LR. Unlike the hydroxyl group of sorbitol， the hydroxyl group of mannitol has a “jagged” distribution and its O_2p orbital is prone to electron delocalization to form strong coordination with Fe³⁺. This will provide a new way to obtain nZVI with high purity and good dispersion by the coordination of alcohol hydroxyl groups.



Preparation of CoO Nanoparticles/Hollow Graphene Nanofiber Composites and Its Electrochemical Performances

HU Shiying, SHEN Jiayan, HAN Junshan, HAO Tingting, LI Xing

2023, 44(2):  20220462.  doi:10.7503/cjcu20220462

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Using the graphenes and Co（CH₃COO）₂·4H₂O as raw materials， the CoO nanoparticles/hollow graphene nanofiber composites were synthesized by the ultrasound-assisted method as the anode materials for lithium-ion batteries. X-ray diffraction（XRD） was used to determine the phase compositions of the materials， scanning electron microscope（SEM） and transmitting electron microscope（TEM） were used to observe the surface morphologies and microstructures of the materials， and X-ray photoelectron spectroscopy（XPS） was used to determine the valence structures of the materials. Cyclic voltammetry， galvanostatic charge and discharge， and AC impedance spectroscopy tests were performed on the materials to characterize its electrochemical performances. The electrochemical performances of the composite materials showed that the reversible capacity still exceeded 800 mA/g and the coulombic efficiency was above 99% at a current density of 100 mA/g after 160 cycles. The excellent electrochemical performances were attributed to the hollow fiber structures of graphenes. The prepared materials exhibited two very excellent characteristics： one was that the hollow interior could contain electrolytes， which would directly transport ions to the particle surfaces， realizing rapid ion transmission； second， the two-dimensional hollow fibers were built into a three-dimensional network structures to realize a three-dimensional electronic conduction network.



Transfer Learning Modeling for Predicting the Methane and Hydrogen Delivery Capacity of Metal-organic Frameworks

CHEN Shaochen, CHENG Min, WANG Shihui, WU Jinkui, LUO Lei, XUE Xiaoyu, JI Xu, ZHANG Changchun, ZHOU Li

2023, 44(2):  20220459.  doi:10.7503/cjcu20220459

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As critical energy resources， methane and hydrogen have been limited in large-scale applications due to their difficulty in storing at low pressure. Metal-organic frameworks（MOFs） are promising materials for gas delivery due to their highly tunable nanoporous structures. At present， machine learning（ML） has been used to assist in the screening of high-performing MOFs， but the traditional ML modeling needs to pay a high cost to obtain a large amount of data， when the amount of data is insufficient， the availability of ML will be greatly reduced. In this paper， based on deep neural network（DNN） and transfer learning（TL）， TL models are established using a small amount of data to accurately predict the methane and hydrogen delivery capacity of a large number of MOFs to reduce modeling costs and quickly respond to the changing delivery standards. Before TL modeling， six geometric descriptors of 12020 MOFs based on experimental synthesis are calculated， covering the largest cavity diameter， pore limiting diameter， density， accessible volumetric surface area， accessible mass surface area， void fractions， and grand canonical Monte Carlo simulation is used to calculate the delivery capacity data of methane and hydrogen by these MOFs. The first step of TL modeling is to train a DNN［Source task（ST） model］ with a coefficient of determination（R^{\mathrm{2}}） of 0.973 using methane delivery capacity data from 8414 MOFs at 298 K/65 bar—298 K/5.8 bar（1 bar=0.1 MPa）. Since then， partial parameters of the ST model are frozen， and data of 100 MOFs delivering methane at 233 K/65 bar—358 K/5.8 bar（Task 1， T1） and 100 MOFs delivering hydrogen at 198 K/100 bar—298 K/5 bar（Task 2， T2） are used， the ST model is fine-tuned twice to obtain two TL models， and the 11820 data in T1 and T2 are predicted， with R² of 0.968 and 0.945， respectively， which are higher than other five traditional ML models. In addition， TL models have high precision and high stability in predicting small data sets and do not produce bad prediction results. Finally， the permutation feature importance is used to measure the importance of descriptors. For the three models of different tasks（ST， T1， and T2）， accessible mass surface area（AMSA）， accessible volumetric surface area（AVSA）， and void fraction（VF） are the most important descriptors for these models， and there is a large amount of shared “know⁃ledge” between the models. On this basis， the relationship between important descriptors and delivery capacity is shown. It provides an efficient research method for future researches on other advanced nanoporous materials to deliver methane and hydrogen.



Synthesis and Tribological Properties of Polyurethane Microcapsules Based on TDI and IPDI

ZHANG Rui, YANG Qi, CHEN Sijia, WANG Lijuan, ZHAO Zenghui, CUI Yuchao, TIAN Yuxuan

2023, 44(2):  20220444.  doi:10.7503/cjcu20220444

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As a new material category being researched and developed in practical application， self-lubricating materials still have the ability to reduce degradation， provide lubrication effect and prolong the service life of materials after structural damage. In this paper， ionic liquid@polyurethane（PU） microcapsules were prepared by in⁃situ polymerization with toluene diisocynate（TDI） and isophorone diisocyanate（IPDI） as the monomer， respectively， and epoxy resin composites were prepared by blending ionic liquid@PU with epoxy resin. The surface morphology of the composite and microcapsule was analyzed by scanning electron microscopy. The mechanical and tribological properties of the microcapsule modified composite were investigated by electronic universal testing machine and friction and wear testing machine under different conditions. The microcapsules were characterized by Fourier transform infrared spectroscopy. The results show that the microcapsules with IPDI as the monomer had more excellent tribological performance， and with the increase of dosage of microcapsule， the tribological properties of the composite material increased significantly. When microcapsule adding amount was 20%， the microcapsule- containing composite material had a low friction coefficient of sliding friction and the surface was relatively smooth， This is because in the experimental process， with the damage of the microcapsule wall material， the ionic liquid of the core material is released， forming dense lubrication film.



Theoretical Study on the Strain Energy and Reorganization Energy Based on Planar Grid Benzothiophene

PENG Xinzhe, GE Jiaoyang, WANG Fangli, YU Guojing, RAN Xueqin, ZHOU Dong, YANG Lei, XIE Linghai

2023, 44(2):  20220313.  doi:10.7503/cjcu20220313

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Organic semiconductor materials are widely used in organic light-emitting diodes（OLEDs）， organic field-effect transistors（OFETs）， and organic solar cells（OSCs）， but they still have some defects， such as poor mobility， which are not conducive to electron transport. In this paper， a series of novel organic charge-transporting nanomolecules were designed and studied based on benzothiophene. Then the molecular structure and electronic properties were studied by using density functional theory， such as molecular orbitals， electrostatic potential， ionization potential， electron affinity， and reorganization energy. Furthermore， intramolecular weak interactions and the contribution of each vibrational mode to the reorganization energy were estimated using non-covalent interaction（NCI） analysis and normal mode analysis， respectively. The results showed that the reorganization energy decreased with the increase of benzothiophene and gridization effect. Compared with the monomer， the electron and hole reorganization energies were reduced by at least 0.394， and 0.056 eV， respectively， which proves that gridization effect is an effective way to reduce the reorganization energy.



Polymer Chemistry

Molecular Dynamics Simulation of Structural Variations of Ionic Polymeric Vesicles under Electric Field

LI Jichen, CAI Shanshan, PENG Jubo, LI Hongfei, DUAN Xiaozheng

2023, 44(2):  20220553.  doi:10.7503/cjcu20220553

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Using coarse-grained molecular dynamics simulations， we studied the deformation and break of ionic polymeric vesicles under the external electric field. We systematically analyzed the structural variations of the polymeric vesicles during the breaking process（including deformation degree and break rate of the vesicles and redistri-bution of each component， etc.） and the structure of the disassembled vesicles. Our study shows that under the weak electric field， the adhered polyelectrolyte preferentially desorb from the vesicle surface， and the vesicle undergoes a spherical-to-ellipsoidal transition. As the electric field strength increases， the ionic side-groups of ionomer are rearranged， and the ordered structure of the vesicle surface charge is wrecked， resulting in vesicle collapse. The collapsed vesicle further disassembles into the ionomer clusters or tiny ionomer aggregates， which are uniformly dispersed in the solution. Our simulations clarify the mechanism for the breaking process of the ionic polymeric vesicle induced by electric field application on a molecular level， and provide insights into the development of drug release technologies.



Magnetic Gradient Slippery Surfaces with Shape Memory Property for Smart Sliding Control of Superparamagnetic Droplet

HU Dongdong, LAI Hua, LIU Yuyan, SONG Yingbin, LUO Xin, ZHANG Dongjie, FAN Zhimin, XIE Zhimin, CHENG Zhongjun

2023, 44(2):  20220442.  doi:10.7503/cjcu20220442

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A kind of magnetic material with gradient shape was prepared， which is composed of magnetic particles and shape memory polymers. After further coating the dimethyl silane lubricant， we obtained a magnetic gradient slippery surface. A superparamagnetic droplet can self-transport directionally on the surface under the effect of magnetic gradient. Meanwhile， reversible control of surface morphology can be achieved based on the shape memory effect， which is favorable for on/off control of droplet sliding. Based on the above two merits， the combination of directional self-transportation and on/off sliding control was successfully achieved. In addition， we also investigated the influence of magnetic particles content on the shape memory property of materials in detail and the relationship between the deformation size of surface morphology and superparamagnetic droplet sliding performance. The mechanism analysis further demonstrates that the self-transportation of superparamagnetic droplet is driven by the directional force provided by magnetic field gradient， the resistance can be increased/eliminated during droplet self-transportation by the reversible control of the morphology of the surface. The synergistic effect of these two factors endows the surface with excellent manipulation of superparamagnetic droplet.