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10 September 2024, Volume 45 Issue 9

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Cover and Content of Chemical Journal of Chinese Universities Vol.45 No.9(2024)

2024, 45(9):  1-5. 

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Review

Research Progress on Luminescence Performance of Double Perovskite Quantum Dots Regulated by Ion Doping

ZHANG Liyuan, WANG Chasina, HU Jingxiang, ZHAN Chuanlang

2024, 45(9):  20240126.  doi:10.7503/cjcu20240126

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Lead based halide perovskite luminescent materials have attracted much attention due to their excellent properties such as flexible crystal structure， tunable bandgap， defect tolerance， and high fluorescence quantum yield. However， the toxicity of lead metal and the stability of perovskite have always been issues that hinder its commercial application and urgently need to be addressed. Therefore， exploring greener and more environmentally friendly non lead metal halide perovskite luminescent materials is becoming an increasing research topic. In recent years， non lead double perovskite structures， in which lead ions are replaced with monovalent and trivalent metal ions， have successfully achieved low toxicity and high stability， but their photoluminescence efficiencies are extremely low due to the indirect bandgap or parity-prohibited direct bandgap. To address this issue， scientists have explored ion doping strategies and successfully achieved a significant improvement in photoluminescence efficiency. In this article， the crystal structure and luminescent properties of non lead double perovskite materials are summarized. Second， the effects of doping with main group metals， rare earth metals， and transition metals on the luminescence performance and luminescent mechanism are summarized. Finally， the application of ion doping strategies and improving the performance of non lead perovskite luminescent materials are summarized and discussed.



Article: Inorganic Chemistry

Beta@ZIF-67 Composite for Catalytic Degradation of Polylactic Acid Plastics

WANG Chenzhu, GAO Mingkun, GAO Yanjing, QI Sixian, YU Jihong

2024, 45(9):  20240221.  doi:10.7503/cjcu20240221

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Biodegradable plastics， such as polylactic acid（PLA）， are preferable to traditional petroleum-based plastics. However， the natural degradation of PLA takes a long time and releases CO₂. Therefore， upcycling PLA is a better option for achieving sustainable development. In this study， a Beta@ZIF-67 composite was developed for efficient catalytic degradation of waste PLA plastics， which was achieved by growing the zeolitic imidazolate framework-67（ZIF-67） on the surface of Beta zeolite. As a result， the real-life PLA plastics were completely converted to methyl lactate in just 4 h at 180 ℃ with a yield up to 76.4%. The high catalytic efficiency was attributed to the composite's open pore structure， large specific surface area， and the synergistic effect of the active sites provided by ZIF-67（Lewis acid/base） and Beta zeolite（Brønsted acid）. Overall， this study provides a new way for designing and synthesizing zeolite-based composite catalysts， which show promising applications in the catalytic degradation of plastics.



Preparation of Micron Plate Sm₂O₃ Fillers Reinforced High-density Polyethylene Composites for Neutron and Gamma Radiation Shielding

LU Yidong, HUO Zhipeng, ZHANG Hong, ZHONG Guoqiang

2024, 45(9):  20240142.  doi:10.7503/cjcu20240142

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Samarium oxide （Sm₂O₃）/boron carbide （B₄C）/high-density polyethylene （HDPE） composites are respectively prepared by using synthesized Sm₂O₃ fillers （Sm₂O₃-I） and commercial Sm₂O₃ fillers （Sm₂O₃-II） for neutron and gamma radiation shielding. The X-ray diffraction （XRD） patterns reveal that the phase of Sm₂O₃-I fillers is a cubic crystal system， body-centered cubic lattices， and its space group is Ia\overline{\mathrm{3}}（206）. However， Sm₂O₃-II fillers have two phases. One is a monoclinic crystal system， simple monoclinic lattices， and its space is C2/m（12）. The other one is a cubic crystal system， body-centered cubic lattices， and the space group is Ia\overline{\mathrm{3}}（206）. Field emission scanning electron microscopy（FESEM） and specific surface area analyses reveal that the micromorphology of Sm₂O₃-I fillers is micron plate with silt and its Brunauer-Emmett-Teller（BET） specific surface area（S_BET） is 5.15 m²/g， while irregularly shaped Sm₂O₃-II fillers have two kinds of micromorphology caused by the two phases of Sm₂O₃-II fillers， which are plate-like agglomeration and agglomeration without specific shape， and the S_BET of Sm₂O₃-II fillers is 2.47 m²/g. The melting temperature （T_p） and yield strength （σ_y） of the synthesized Sm₂O₃-I/B₄C/HDPE composites are respectively 140.6 °C and 22.6 MPa， which are better than the commercial Sm₂O₃-II/B₄C/HDPE composites. The neutron and gamma radiation shielding tests reveal that the synthesized Sm₂O₃ fillers with even size and high BET-specific surface area can improve the neutron and gamma radiation shielding performance of composites. 10%Sm₂O₃-I/20%B₄C/70%HDPE（mass fraction） with a thickness of 15 cm has a neutron radiation shielding rate of 98.4% under the ²⁵²Cf neutron source and a gamma radiation shielding rate of 71.7% under ¹³⁷Cs gamma source.



Analytical Chemistry

Preparation of NPCl-CDs/Fe ³⁺ Fluorescent Probe and the Detection for L -Cys

XU Xiaohua, WANG Li, LIN Pengcheng, MA Tianfeng, SHI Lin, WANG Huan, LU Yongchang

2024, 45(9):  20240251.  doi:10.7503/cjcu20240251

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In this work， a blue-green NPCl-CDs was synthesized by one-step hydrothermal method using glucose， ethylenediamine， concentrated hydrochloric acid and concentrated phosphoric acid as reaction precursors. Then NPCl-CDs/Fe ³⁺ fluorescent probe was constructed for the quantitative detection of L-Cys in actual samples. The fluorescence intensity of NPCl-CDs could be quenched after addition of Fe ³⁺. The fluorescence intensity of the NPCl-CDs/Fe ³⁺system was restored when L-Cys was introduced into the system. Therefore， a novel "on-off-on" NPCl-CDs/Fe ³⁺- L-Cys fluorescence sensing system for L-Cys quantitative detection was constructed. This experiment showed a wide linear region in the concentration range of 5.8—60.0 µmol/L with a detection limit of 0.052 µmol/L. The results indicated that the fluorescence sensing system had good selectivity， sensitivity and potential application value for the detection of L-Cys in real samples.



Rapid Determination of D⁃（+）⁃Glucose in Urine Using Surface⁃enhanced Raman Spectroscopy

ZHANG Yu, CHEN Long, WANG Zhongcai, HU Guang, XU Dong, SHENG Quankang, CHEN Ao, CHEN Shaoyun, HU Chenglong, CHEN Jian

2024, 45(9):  20240215.  doi:10.7503/cjcu20240215

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The silver（Ag） snowiness micro-nanostructures with a large aspect ratio was prepared by the polyol reduction method， and it was used as the substrate for surface enhanced Raman scattering（SERS）. Rhodamine 6G（R6G） was used as the probe molecule to study the SERS effect of Ag nanowires. The results showed that the minimum detection concentration of R6G on Ag nanowires was 10^‒10 mol/L， and the enhancement factor（EF） was about 1.0×10⁴. The relative standard deviation（RSD） calculated based on the scattering peak intensities of 610 and 772 cm^‒1 was 14.66% and 13.75%， respectively， indicating that the SERS signal intensity distribution of R6G on Ag nanowires substrate was relatively uniform to lead to good signal reproducibility. In addition， Ag nanowires were used as SERS substrates to detect low levels of D-（+）-glucose in urine. It was found that the detection limit of Ag nanowires for D-（+）-glucose concentration was as low as 10^‒6 mg/mL， and the RSD value was less than 8%， indicating that Ag nanowires had good sensitivity and signal reproducibility for trace detection of D-（+）-glucose. This study could provide some technical support for blood glucose monitoring and early prevention of diabetes.



Prediction of Deep Vein Thrombosis Based on GC-MS and Machine Learning

HOU Zejin, LI Rongqi, LI Jian, FENG Yining, JIN Qianqian, SUN Junhong, CAO Jie

2024, 45(9):  20240199.  doi:10.7503/cjcu20240199

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This study investigated the changes of endogenous metabolites in the serum of deep vein thrombosis（DVT） rats， screened characteristic metabolites related to DVT， and constructed the prediction models for clinical diagnosis and forensic identification of DVT. The DVT rat model was constructed using the inferior vena cava ligation method， and blood samples were collected 72 h post-surgery. Gas chromatography-mass spectrometry（GC-MS） was used to analyze the small molecule metabolism profile in the rat serum. Then， orthogonal partial least squares discriminant analysis combined with the Mann-Whitney U test initially identified 22 differential metabolites associated with DVT， involving metabolic pathways， such as glyoxylate and dicarboxylate metabolism， tricarboxylic acid cycle（TCA cycle）， and alanine， aspartate and glutamate metabolism. Subsequently， a feature selection method based on the random forest classification algorithm（Boruta） was applied to screening out 13 characteristic metabolites correlated with DVT from the differential metabolites and predictive models for DVT were constructed using 3 machine learning algorithms（logistic regression， linear discriminant analysis and Adaboost ensemble learning algorithm）. The results showed that the DVT prediction model of linear discriminant analysis has a high performance with an accuracy of 87%， as well as precision of 0.88， recall of 0.86， F1 score of 0.87， and area under the receiver operating characteristic curve（AUROC） of 0.95. The research indicates that the DVT prediction model constructed using GC-MS metabolomics combined with machine learning algorithms can provide technical support for the diagnosis， treatment， and forensic identification of DVT.



Organic Chemistry

Synthesis， Photochromism and Fluorescence of Naphthopyran-tetraphenylethylene Hybrid

LIU Kejun, WEI Ruiqi, ZHOU Ruiyuan, SHEN Ripei, HAN Jie

2024, 45(9):  20240201.  doi:10.7503/cjcu20240201

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A novel class of naphthopyran-tetraphenylethylene hybrids NP1—NP5 were designed and synthesized， and their photochromic and fluorescent properties were investigated in detail. Compared to 2，2-diphenyl-2H-benzo［h］chromene（NP0）， the thermal fading rate of NP5 has significantly improved with the fastest half-time（τ_1/2） of 0.75 min. Such kind of compounds also exhibited fast photo-responsive speed and excellent fatigue resistance. In addition， the tetrahydrofuran solution of NP2 is fluorescent， which can be quenched by an irradiation with 360 nm UV light. However， no aggregation-induced emission was observed for these compounds.



［3+2］ Cyclization Addition of N-cyclopropyl Aniline in a Non-metallic Photocatalytic System

ZHANG Xiaofei, TIAN Pengcheng, CHANG Jingjing

2024, 45(9):  20240253.  doi:10.7503/cjcu20240253

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Cyclopentane structure is widely present in natural products and drug molecules， and is one of the important core skeletons in the synthesis of small molecule drugs. In this conversion， 19 kinds of cyclopentane derivatives were obtained with good to excellent yields and satisfied diastereoselectivity using N-cyclopropylaniline and 2-［acetoxy（phenyl）methyl］acrylate as starting materials. It is worth mentioning that one pure distereoisomer could be separated just by column chromatography. This protocol features mild conditions， broad substrate scope， green economy， giving a new pathway for the synthesis of cyclopentane and new application of Eosin Y in the field of photocatalytic synthesis.



Physical Chemistry

Study of Ozone Elimination via Chlorine Radical Chain Reaction Under Visible Light

ZHAO Ziwang, CONG Shurui, WANG Chunyu, ZHOU Shuyuan, PENG Meng, WANG Lei, XU Jiayu

2024, 45(9):  20240187.  doi:10.7503/cjcu20240187

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The concentration of ozone（O₃） in our atmosphere has increased， which makes O₃ a crucial pollutant in the prevention of air pollution. The photocatalytic reaction based on hydroxyl radical has low ozone elimination performance， and the modification method that only increases the production of hydroxyl radical is not suitable for ozone photocatalytic elimination. In this paper， a series of Fe-Bi₂WO₆@TiO₂ composites were prepared by Fe doping and TiO₂ supporting successively based on Bi₂WO₆. A series of physical properties characterization and ozone catalytic activity tests were carried out for the composites. The results show that Fe-Bi₂WO₆@TiO₂ has a typical coating structure， exhibits visible light response， and stimulates the formation of chlorine radicals. Chlorine radicals act as active species for eliminating O₃， driving a photochemical reaction mechanism similar to the "ozone hole effect"， that is， the surface chlorinated TiO₂ was photoexcited to produce chlorine radicals，triggering a chain reaction，and greatly improving the ozone decomposition performance. The maximum elimination rate of O₃ by Fe-Bi₂WO₆@TiO₂ is 93%. The introduction of chlorine radical and the expansion of visible light response of the composite can greatly improve the photocatalytic ozone elimination ability.



Catalytic Behavior of Different Amounts of WO₄ Active Sites on Na-W-Mn/SiO₂ Catalysts for Oxidative Coupling of Methane

SONG Jiaxin, FAN Xiaoqiang, LIU Baijun, ZHAO Zhen

2024, 45(9):  20240174.  doi:10.7503/cjcu20240174

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Oxidative coupling of methane（OCM） served as a direct pathway for producing C₂（C₂H₆ and C₂H₄） has received widespread attention. Among the conventional catalysts， Mn/Na₂WO₄/SiO₂（Na-W-Mn/SiO₂） catalysts have many advantages like： high methane conversion， high C₂ selectivity， and relatively high stability even at high temperature. In this work， a series of Na-nW-Mn/SiO₂ catalysts with different W loadings were prepared using silicotungstic acid as the precursor. In order to further investigate the effects of W loadings on the structure and OCM performance of the catalysts， X-ray diffraction（XRD）， transmission electron microscopy（TEM）， hydrogen temperature programmed reduction（H₂-TPR）， oxygen temperature programmed desorption（O₂-TPD）， and X-ray photoelectron spectra（XPS） characterizations and the activity evaluation for oxidative coupling of methane were performed on all samples. The results demondtrated that there is a strong interaction among the crystal phases of Na₂WO₄， Mn₂O₃ and α-cristobalite， which enhances the OCM performance of these catalysts through synergistic catalysis. It is interesting that with the continuous increase of W loading， the W species maintained the form of tetrahedral WO₄ on the surface of catalysts. Structure-activity relationship analysis shows that tetrahedral WO₄ is the active center for the OCM reaction on this series of catalysts. Therefore， the Na-10.0%W-Mn/SiO₂ catalyst with high tetrahedral WO₄ content has a lower reduction temperature from W⁶⁺→W⁴⁺ and a higher proportion of surface lattice oxygen， which may be the main reason for its optimal methane conversion and C₂ yield. When the temperature reached 775 ℃， the conversion of methane over Na-10.0%W-Mn/SiO₂ catalyst is 44.2%， the yield of C₂ is 24.1%， and the yield of ethylene is 18.7%.



Direct Synthesis of Acetic Acid from CH₄-CO₂ over Pd/LDH at Low Temperature

WU Yixiao, LIU Chaobo, ZAN Xueyu, ZHANG Chaoyu, TAO Shiqi, LI Zhiwen, WANG Kejing, LIU Yongjun, HUANG Wei

2024, 45(9):  20240125.  doi:10.7503/cjcu20240125

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The direct synthesis of acetic acid from CH₄ and CO₂ is an effective method for converting CH₄ and reducing CO₂ emissions in a 100% atom economy reaction. Hydrotalcite is widely used in CH₄ and CO₂ conversion reactions due to their large specific surface area， high thermal stability， good dispersion of active metals， and suitable acid-base properties， while Pd is often considered as the active center for C—C bond coupling. Herein， a series of Pd/LDH catalyst with Pd loading of 5%（mass fraction） was prepared by ion-exchange method using magnesium-aluminum hydrotalcite（MgAl-LDH） with Mg/Al molar ratios of 1.5， 3， 5， 7 and 9 as the carrier， and applied for the direct synthesis of acetic acid from CH₄-CO₂ by a two step-wise technique. The structure and surface acidity-alkalinity of the catalyst were analyzed by XRD， ICP， N₂ adsorption-desorption， XPS， NH₃-TPD， CO₂-TPD and in situ DRIFTS. The results showed that the yield of acetic acid over MA5 catalyst with Mg/Al molar ratio of 5 was the highest（61.8 μmol·g{}_{\mathrm{c}\mathrm{a}\mathrm{t}}^{-\mathrm{1}}·h^-1）， and acetic acid was the only product in the liquid phase product. Its yield was positively correlated with the amount of medium strong acid and surface Pd⁰/（Pd²⁺+Pd⁰） ratios. The rapid inactivation of the catalyst was due to the collapse of the hydrotalcite structure， which resulted in a significant decrease in the amount of medium strong acid. In situ DRIFTS experiments showed that CH₄ was firstly dissociated to form CH _x^* intermediate and H proton on the catalyst surface， then CO₂ was directly inserted into CH_x^* to form CH _x COO^*， with further hydrogenated to yield acetic acid， or CO₂ was combined with H protons to form COOH^* intermediates which were then coupled with CH _x^{* to form CH _x COOH*， and finally hydrogenated to obtain acetic acid.}



Electrochemical-mechanical Simulation of Ternary Cathode Materials with Core-shell Structure for Lithium-ion Batteries

GOU Lei, YANG Zheqi, YU Jinhua, FAN Xiaoyong, LI Donglin, LI Hui

2024, 45(9):  20240259.  doi:10.7503/cjcu20240259

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Ternary cathode material LiNi _x Co _y Mn _z O₂（NCM） with a core-shell structure is one of the key materials for the development of lithium-ion batteries with high specific capacity and long term cycle stability. However， stress-induced mechanical failure is one of the main factors that would lead to the capacity decay of such types of electrode materials. In order to better understand the stress distribution and evolution in the core-shell structural cathode during the electrochemical reaction process， a three-dimensional multiphysics lithium-ion battery model for electrochemistry-mechanics coupling was constructed in this paper. The distribution and evolution of Li⁺ concentration， strain and stress in the core-shell cathode during the discharge process were first obtained through the model， and then the effects of various discharge rates， shell thicknesses， and core radiuses on the strain-stress at the end of the discharge were investigated. The results show that stresses at the centre of the particle and the core-shell interface rapidly reach their maximum at the beginning of the discharge， and then undergo a gradual decreasing process with the prolonged diffusion process of Li⁺. The binder and neighboring particles have significant effects on the stress distribution in this cathode. Decreasing the discharge rate and core radius， as well as increasing the shell thickness， can reduce the stress in the cathode. The obtained conclusions can provide a reference for the design and optimization of core-shell cathode structures as well as discharge strategies for lithium-ion batteries.



Co Based Carbon Materials as Bifunctional Catalysts for Efficient Degradation of Ciprofloxacin in Electro-Fenton System

WANG Shuang, LYU Yueqin, LIU Xingyu, LI Yi

2024, 45(9):  20240247.  doi:10.7503/cjcu20240247

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The overuse of antibiotics has resulted in a significant accumulation of ciprofloxacin（CIP） and its degradation intermediates in the environment， posing a threat to the environment and human health. In recent years， it has been considered a promising method to use heterogeneous electron-Fenton technology for antibiotic pollution treatment. In this study， we used organic metal framework ZIF-67 as precursor， and prepared a series of Co based carbon electrocatalysts（Co-NC-T） under different temperatures. The successful formation of the catalysts was confirmed by morphology and crystal structure analysis， including scanning electron microscopy， high-resolution transmission electron microscopy and X-ray diffraction patterns. On the one hand， The results of X-ray photoelectron spectroscopy showed that Co-NC-900 contained the highest proportion of graphite N， which was beneficial for O₂ to generate H₂O₂ through 2e^‒ reduction reaction. On the other hand， the multiple valence states of Co［Co（0）， Co（Ⅱ）， Co（Ⅲ）］ could promote the conversion of H₂O₂ into various reactive oxygen species during the reaction. The Co-NC-900 catalyst could simultaneously promote the formation and activation of H₂O₂， which was beneficial for the degradation of CIP. The quenching experiment and electron spin resonance experiment results indicated that the main reactive oxygen species in the system were ·O₂^‒ and ·OH. Reactive oxygen species could synergistically participate in the reaction， thereby improving the degradation efficiency of CIP. Under pH=3， the removal rate of Co-NC-900 to CIP was 94.5% in 120 min. This study provided theoretical guidance for the efficient degradation of CIP in wastewater.



Ionic Liquid-assisted Hydrothermal Synthesis of 1T-MoS₂ and Its Zinc Ion Storage Performance

WANG Lu

2024, 45(9):  20240145.  doi:10.7503/cjcu20240145

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A 1T-MoS₂ nanosheets array with expanded interlayer spacing was synthesized on carbon cloth（CC） using an ionic liquid-assisted hydrothermal method. As a positive electrode material for zinc ion batteries， 1T-MoS₂/CC exhibits a discharge specific capacity of 194.2 mA·h/g at 0.1 A/g current density， and can still maintain a capacity retention rate of 95.5% after 750 cycles at a high current density of 1 A/g. The excellent zinc ion storage capacity of 1T-MoS₂/CC can be attributed to：（1） ionic liquids promote the formation of 1T phase， with a 1T-MoS₂ phase content of about 78% in the nanoarray， and a high concentration of 1T phase content gives it a good charge transfer rate； （2） the insertion of ionic liquids between 1T-MoS₂ layers increases the interlayer spacing to 1.06 nm， which can reduce the energy barrier during the insertion process of hydrated zinc ions； （3） the three-dimensional structure of carbon cloth can inhibit the aggregation of MoS₂ nanopages and promote sufficient contact between 1T-MoS₂/CC and electrolyte.



Polymer Chemistry

Directional Removal of Water Droplets by Magnetic Responsive Polydimethylsiloxane Arrays

TIAN Yongtu, ZHANG Yang, LI Hongjie, LAI Hua, CHENG Zhongjun

2024, 45(9):  20240220.  doi:10.7503/cjcu20240220

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In this paper， superhydrophobic low-adhesive magnetically responsive polydimethylsiloxane（PDMS） columnar arrays（SMPA） were prepared by combination of template method and surface modification. The columnar arrays can undergo reversible bending deformation under the action of the magnetic field， and the degree of bending will increase with the increase of the strength of the applied magnetic field and the increase of the content of magnetic particles in the columnar arrays. The findings indicate that， when the surface area of the columnar arrays remains constant， the dynamic magnetic response structure exhibits enhanced capability in removing smaller water droplets from the surface compared to its static counterpart， and droplets departure direction and volume are closely related to the structural parameters and bending angle of the columnar arrays. Based on the magnetic field， smart control of droplets jumping in both departing direction and droplets volume can be achieved.



Coordination Copolymerization of Ethylene with Vinyl Pentamethyldisiloxane

ZHANG Danfeng, GAO Chunxuan, HUANG Hailin

2024, 45(9):  20240205.  doi:10.7503/cjcu20240205

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Owing to the unique “chain walking” mechanism and tolerance of polar groups， post-transition metal catalysts can be utilized for the copolymerization of α-olefin with polar monomers， resulting in the production of high-quality functional polyolefins with desired structure and properties. In this study， under the activation of ethylaluminum sesquichloride， the coordination copolymerization of ethylene with vinyl pentamethyldisiloxane （VPMDSO） using α-diimine nickel（II） complexes（C1—C6） as catalysts was performed. The effects of VPMDSO monomer concentration， catalyst dosage， Al/Ni molar ratio， ethylene pressure， polymerization time， solvent， and catalyst structure on copolymerization were examined， and the optimal polymerization conditions were obtained. The microstructures， silicon content， thermal stability and surface energy of the copolymer were characterized by proton nuclear magnetic resonance（¹H NMR）， Fourier transform infrared（FTIR） spectroscopy， gel permeation chromato-graphy（GPC） analysis， thermogravimetry analysis（TGA） and contact angle measurement. The results show that the copolymerization catalytic activity of α-diimide nickel（II） complex could reach to 1.26×10⁶ g·mol{}_{\mathrm{N}\mathrm{i}}^{-\mathrm{1}}·h^-1 while the silicon content range between 0.25% to 0.87%. Compared to polyethylene， the surface energy of the copolymer films decreased and the hydrophobicity increased.