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Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-Dong Li Hong Li Lu-Kun Feng Feng Bao Ming-Liang Wang Cai-Zhen Zhu Zhao-Hui Zheng Xiao-Bin Ding Jian Xu Chengdu institute of Organic chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

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Polyoxometalate as the assembly material to self-assembled Ni(OH)_(2) nanosheets with electrocatalytic performance

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Nano Research 2024年第8期17卷 7061-7067页

作者： Danyang He Tianyang Li Luozhen Jiang Fei Wang Zihao Xing Nan Wang Zhiyu Jia Guo-Yu Yang Key Laboratory of Cluster Science Ministry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China Shanghai Advanced Research institute Chinese Academy of ScienceShanghai 201210China Key Laboratory of Polyoxometalate and Reticular Material chemistry of Ministry of Education Facluty of ChemistryNortheast Normal UniversityChangchun 130024China

Developing non-noble metal-based electrocatalyst with high catalytic activity is essential for advancing hydrogen energy *** study introduces a hydrothermal method for synthesizing order Ni(OH)_(2) nanosheets,with H_(3)O_(40)PW_(12)(denoted as PW_(12))loaded onto reduced graphene oxide(rGO)coated on nickel foam(referred to as PW_(12)-Ni(OH)_(2)/rGO).This method contrasts with the electrodeposition of Ni(OH)_(2),where PW_(12) is added to the synthetic system to direct the assembly and morphology of the Ni(OH)_(2) through a hydrothermal *** this work,the nickel foam acts dual roles as both the substrate and the source of nickel for the formation of Ni(OH)_(2).The PW_(12)-Ni(OH)_(2)/rGO nanosheets,when successfully prepared and loaded onto the nickel foam(NF),exhibited superior electrocatalytic activity for the hydrogen evolution reaction(HER)in an alkaline electrolyte,achieving a current density of 10 mA·cm^(-2) at an overpotential of 69 ***,we endeavored to expand the application of this material towards the oxygen evolution reaction(OER)by preparing PW_(12)-(Fe/Co)Ni(OH)_(2)/rGO through the addition of metal *** nanocomposite displayed outstanding electrocatalytic activity in alkaline electrolytes,with a current density of 10 mA·cm^(-2)at an overpotential of 211 mV,and demonstrated excellent stability over a 50 h period in a 1 M KOH *** results presented in this paper offer an effective strategy for the preparation of polyoxometalate-based inorganic materials with diverse functionalities,applicable to both HER and OER.

关键词： polyoxometalate Ni(OH)_(2) assembly hydrogen evolution reaction oxygen evolution reaction

Defect engineering of W^(6+)-doped NiO for high-performance black smart windows

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Nano Research 2024年第4期17卷 3043-3052页

作者： Yingjun Xiao Xiang Zhang Dukang Yan Jianbo Deng Mingjun Chen Hulin Zhang Wenhai Sun Jiupeng Zhao Yao Li School of chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China Center for Composite Materials and Structure Harbin Institute of TechnologyHarbin 150001China

In this report,W^(6+)doping as a defect engineering strategy has been proposed to improve the electrochromic properties of NiO *** research was conducted to explore the electrochromic properties and the modified mechanism of W-doped NiO *** to the pure NiO,W-doped NiO film exhibits improved electrochromic properties with significant optical modulation(61.56%at 550 nm),fast switching speed(4.42 s/1.40 s for coloring/bleaching),high coloration efficiency(45.41 cm^(2)·C-1)and outstanding cycling stability(no significant attenuation after 2000 cycles)in Li-based *** functional theory(DFT)calculations combined with the experimental results indicate that the improved electrochromic properties were due to enhanced the electronic conductivity and ion conductivity after the introduction of W^(6+).The charge capacity of W-doped NiO has also been improved,and it can function with WO_(3) to achieve a high performance black electrochromic smart window(ECSW)by balancing *** work could advance the fundamental understanding of defect engineering as an effective strategy to boost the electrochromic properties of NiO anodic material,manifesting a significant development as a candidate counter electrode in high-performance black smart windows.

关键词： NiO defect engineering charge balance black electrochromic windows

Programmed DNA walkers for biosensors

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Chinese Chemical Letters 2024年第9期35卷 119-129页

作者： Chang Liu Tao Wu Lijiao Deng Xuzi Li Xin Fu Shuzhen Liao Wenjie Ma Guoqiang Zou Hai Yang School of chemistry and Chemical Engineering Hunan Institute of EngineeringXiangtan 411104China College of chemistry and Chemical Engineering Central South UniversityChangsha 410083China

Nowadays,due to excellent biological and polymeric characteristics,DNA has been widely noted as an emerging building block to construct diverse materials for biosensing,in vivo imaging,drug delivery,and disease ***,relying on programmability,predictability,and stability of DNA,DNA walkers have opened new and exciting opportunities in modern life sciences for target detection and biological analysis,which are constructed by self-assembly of DNA or combining DNA with other nanomaterials(e.g.,quantum dots,gold nanoparticles,magnetic nanoparticles,polymers).Compared with conventional nanomaterials(lanthanide-doped upconversion nanoparticles,magnetic nanomaterials,carbon dots,silicon dots,and so on),DNA walkers showed convenient modification,lower biotoxicity,excellent biocompatibility and high biostability,improving the biological ***,with high-speed operating efficiency and sustainable operation,DNA walkers powered by strand displacement reaction or protein enzyme/DNAzyme reaction,have highly sensitive detection and signal amplification abilities,which are applied in biosensing,material assembly and synthesis,and early cancer ***,DNA walkers could be regarded as signal amplifiers,which enhanced the signal transduction and amplified biosensor sensing ***,we systematically and comprehensively summarized the operating principles of various DNA walkers,categorized rational design of the DNA walker,and outlined the application of DNA walker in ***,the challenges and future trends of DNA walkers were discussed.

关键词： DNA walker Biosensors Signal amplification strategies Operating principles Design strategies

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Highly efficient nitrogen fixation over S-scheme heterojunction photocatalysts with enhanced active hydrogen supply

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National Science Review 2024年第5期11卷 315-325页

作者： Tong Bao Yamin Xi Chaoqi Zhang Peiyang Du Yitong Xiang Jiaxin Li Ling Yuan Chengzhong Yu Chao Liu School of chemistry and Molecular Engineering East China Normal University Australian institute for Bioengineering and Nanotechnology The University of Queensland

Photocatalytic N2fixation is a promising strategy for ammonia（NH3） synthesis;however,it suffers from relatively low ammonia yield due to the difficulty in the design of photocatalysts with both high charge transfer efficiency and desirable N2adsorption/activation ***,an S-scheme CoSx/ZnS heterojunction with dual active sites is designed as an efficient N2fixation *** CoSx/ZnS heterojunction exhibits a unique pocket-like nanostructure with small ZnS nanocrystals adhered on a single-hole CoSxhollow *** the heterojunction,the ele ctronic interaction between ZnS and CoSxcreates electron-deficient Zn sites with enhanced N2chemisorption and electron-sufficient Co sites with active hydrogen supply for N2hydrogenation,cooperatively reducing the energy barrier for *** combination with the promoted photogenerated electron-hole separation of the S-scheme heterojunction and facilitated mass transfer by the pocket-like nanostructure,an excellent N2fixation performance with a high NH3yield of 1175.37 μmol g-1h-1is *** study provides new insights into the design of hetero junction photocatalysts for N2fixation.

关键词： photocatalysis nitrogen fixation S-scheme heterojunction active hydrogen ammonia

A Highly Efficient Ni/Al_(2)O_(3)-LaO_(x) Catalyst for the Reductive Amination of Furfural to Furfurylamine:the Promoting Effect of La

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Chemical Research in Chinese Universities 2024年第1期40卷 36-46页

作者： YANG Yinze ZHANG Liyan ZHOU Leilei CHENG Haiyang ZHAO Fengyu State Key Laboratory of Electroanalytical chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China School of Applied chemistry and Engineering University of Science Technology of ChinaHefei 230026P.R.China Jilin Province Key Laboratory of Green chemistry and Process Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China

The reductive amination of furfural to furfurylamine is an important and still challenging topic in the field of biomass conversion. In this work, we prepared a series of Ni/Al_(2)O_(3)-LaO_(x) catalysts by co-precipitation method, the role of La played in promoting the catalytic performances of reductive amination furfural was discussed based on the changes in the electronic state of Ni species, acidity, and Ni particle size. The catalytic activity and the selectivity of furfurylamine are highly dependent on the surface properties and the structure of the catalyst. The addition of La promoted the amount of strong acidic sites and the H2dissociation and spillover on the surface, thus inducing the improvement of the catalytic activity and furfurylamine selectivity. The Ni/Al_(2)O_(3)-0.5LaO_(x)catalyst with suitable acid sites gave a high yield of furfurylamine (94.9%) under mild reaction conditions. Moreover, the catalyst could be recycled five times without significant loss in activity. The Ni/Al_(2)O_(3)-LaO_(x) catalyst is of great promise in the production of amines via reductive amination reaction.

关键词： Reductive amination Furfural Nickel catalyst Furfurylamine Lanthanum

A novel metal-free porous covalent organic polymer for efficient room-temperature photocatalytic CO2 reduction via dry-reforming of methane

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Green Energy & Environment 2024年第9期9卷 1407-1418页

作者： Sheng-Yan Yin Ziyi Li Yingcai Hu Xiao Luo Jishan Li College of chemistry and Chemical Engineering Hunan University institute of Basic Medicine and Cancer (IBMC) Chinese Academy of Sciences

At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane（DRM） is quite promising and ***,we developed a novel covalent organic porous polymer （TPE-COP） with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas （CO and H2）.Both electron donor (tris（4-aminophenyl）amine,TAPA) and acceptor (4,4',4'',4'''-(（1 E,1'E,1''E,1'''E）-(ethene-1,1,2,2-tetrayltetrakis （benzene-4,1-diyl）)tetrakis （ethene-2,1-diyl）)tetrakis (1-（4-formylbenzyl）quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic *** functional theory （DFT） simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating *** 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g-1for CO and H2,respectively,which are significantly higher than those of TPE-CHO small *** excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of ***,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.

关键词： Metal-free Photocatalytic CO 2 reduction Covalent organic polymer Dry-reforming of methane Electron donor and acceptor

A Tri-Salt Composite Electrolyte with Temperature Switch Function for Intelligently Temperature-Controlled Lithium Batteries

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Energy & Environmental Materials 2024年第6期7卷 84-93页

作者： Ende Fu Huimin Wang Yating Zhang Zhenxue Xiao Xiu Zheng Shuai Hao Xueping Gao institute of New Energy Material chemistry School of Materials Science and EngineeringNankai UniversityTianjin300350 China

The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic *** emerging of intelligent control in kinds of devices brings new requirements for battery *** high-energy lithium batteries are expected to respond or react under different environmental *** this work,a tri-salt composite electrolyte is designed with a temperature switch function for intelligently temperature-controlled lithium ***,the halide Li_(3)YBr_(6)together with LiTFSI and LiNO_(3)works as active fillers in a low-melting-point polymer matrix(polyethyleneglycol dimethyl ether(PEGDME)and polyethylene oxide(PEO)),which is further filled into the pre-lithiated alumina fiber *** 60°C,the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface,effectively minimizing the interfacial resistance and leading to high discharge capacity in the *** electrolyte is changed into a solid state below 30°C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid ***,by simply adjusting the temperature,the cell can be turned“ON”or“OFF”*** novel function of the composite electrolyte has enlightening significance in developing intelligently temperature-controlled lithium batteries.

关键词： composite electrolyte halide electrolyte low melting point solid-state battery temperature switch function

Atmospheric chemistry of 2-nitrobenzaldehyde:Initiated by photo-excitation,OH-oxidation,and small TiO_(2) clusters adsorption catalysis

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Journal of Environmental Sciences 2024年第5期139卷 123-137页

作者： Feng-Yang Bai Xiang-Huan Liu Ting-Ting Meng Zhou Yu Yi-Chen Wang Shuang Ni Zhen Zhao institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034China

The fate of 2-nitrobenzaldehyde(2-NBA)is of interest in atmospheric chemistry as it is a semi-volatile organic compound with high *** study presents a quantum chemical study of the gas-phase reactions of 2-NBA photo-excitation and OH-oxidation in the absence and presence of small TiO_(2) *** further understand the unknown photolysis mechanism,the photo-reaction pathways of ground singlet state and the lying excited triplet state of 2-NBA were investigated including the initial and subsequent reactions of proton transfer,direct CO,NO_(2),and HCO elimination routes in the presence of O_(2) and ***,the OH-mediated degradation of 2-NBA proceeded via five H-extraction and six OH-addition channels by indirect mechanism,which follows a succession of reaction steps initiated by the formation of weakly stable intermediate *** H-extraction from the-CHO group was the dominant pathway with a negative activation energy of-1.22 kcal/*** calculated rate coefficients at 200–600 K were close to the experimental data in literature within 308-352 K,and the kinetic negative temperature independence was found in both experimental literature and computational ***,2-NBA was favored to be captured onto small TiO_(2) clusters via six adsorption configurations formed via various combination of three types of bonds of Ti…O,Ti…C,and O…H between the molecularly adsorbed 2-NBA and TiO_(2) *** indicted that the chemisorptions of aldehyde oxygen have largest *** results suggested adsorption conformations have a respectable impact on the catalysis *** study is significant for understanding the atmospheric chemistry of 2-nitrobenzaldehyde.

关键词： 2-nitrobenzaldehyde OH radical oxidation Rate coefficient Photolysis mechanism Adsorption catalysis

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