检索结果-南通市图书馆

Chinese Journal of Polymer Science 2024年第8期42卷 1085-1092页

作者： Hong-Yu Ji Hong-Liang Mu Chun-Feng Tang Yu-Xing Zhang Yue Chi Zhong-Bao Jian key laboratory of Advanced structural Materials Ministry of EducationSchool of Materials Science and EngineeringChangchun University of TechnologyChangchun 130012China state key laboratory of Polymer Physics and chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

Olefin polymerization is one of the most im portant chemical reactions in *** work presents a strategy that emphasizes the synergistic meta/poro-steric hindrance of N-aryl groups and electronic effects in newly synthesized neutral salicylaldiminato nickel *** nickel(Ⅱ)catalysts exhibit exceptional thermostability,ranging from 30℃to 130℃,demonstrating enhanced catalytic activities and broadly regulated polyethylene molecular weights(3-341 kg·mol^(-1))and controlled polymer branch density(2-102 brs/1000C).The preferred catalyst Ni3 with concerted steric and electronic effects enables the production of solid-state semi-crystalline polyethylene materials at temperatures below 90℃.Notably,Ni3 exhibits an impressive tolerance of 110℃and can withstand even the challenging polymerization temperature of 130℃,leading to the production of polyethylene wax and ***,functionalized polyethylene is produced.

关键词： Polyolefin Salicylaldiminato ligand Nickel catalyst Oil Wax

Copper-catalyzed enantioselective desymmetrizing C(sp^(2))-H functionalization of azide-ynamides via α-imino copper carbenes

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2024年第9期67卷 2982-2988页

作者： En-He Huang Li-Gao Liu You-Wei Yin Hao-Xuan Dong Ji-Jia Zhou Xin Lu Bo Zhou Long-Wu Ye key laboratory for Chemical Biology of Fujian Province and state key laboratory of Physical chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China state key laboratory of Organometallic chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

α-Imino metal carbenes are versatile intermediates in organic synthesis,and have broad applications in the assembly of divergent ***,the catalytic enantioselective desymmetrization based onα-imino metal carbenes has not been developed to ***,we disclose an enantioselective desymmetrizing C(sp^(2))-H functionalization of azide-ynamides viaα-imino copper carbenes,leading to the efficient assembly of divergent chiral indoloazepines in generally moderate to excellent yields with high ***,this reaction represents the first enantioselective desymmetrization based onα-imino metal *** synthetic transformations and biological tests show the potential utility of this ***,computational studies are employed to elucidate the reaction mechanism and the origin of enantioselectivity.

关键词： enantioselective desymmetrization metal carbenes copper catalysis nitrene transfer alkynes

Recovering noble metals from waste streams using porous organic frameworks for heterogeneous catalysis

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2024年第11期67卷 3578-3587页

作者： Yu Pan Michelle ?hlén Maria Str?mme Chao Xu Division of Nanotechnology and Functional Materials Department of Materials Science and Engineering ?ngstr?m LaboratoryUppsala University state key laboratory of structural chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Recovering noble metals from waste resources and incorporating them into catalysts stands out as a promising strategy for advancing sustainability within the catalysis field. This review provides a comprehensive overview of recent investigations into noble metal recovery from waste streams, specifically employing porous organic frameworks(POFs). Additionally, the study delves into the utilization of the resultant composites, enriched with noble metals, in heterogeneous catalysis. Moreover, we offer insights into the challenges faced and outline prospects for the practical implementation of extracting noble metal catalysts from waste streams using POFs, aiming to develop cost-effective, sustainable, and efficient heterogeneous catalysts.

关键词： porous organic frameworks noble metal recovery heterogeneous catalysis sustainability

Rapid and controllable in-situ self-assembly of main-group metal nanofilms for highly efficient CO_(2)electroreduction to liquid fuel in flow cells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5718-5725页

作者： Miao Wang Huaizhu Wang Yaoda Wang Junchuan Liang Mengfei Zhu Jiarui Li Zuoxiu Tie Zhong Jin state key laboratory of Coordination chemistry MOE Key Laboratory of Mesoscopic ChemistryMOE Key Laboratory of High Performance Polymer Materials and TechnologyJiangsu Key Laboratory of Advanced Organic MaterialsTianchang New Materials and Energy Technology Researc

The electrocatalytic reduction of CO_(2)is a promising pathway to generate renewable fuels and ***,its advancement is impeded by the absence of electrocatalysts with both high selectivity and ***,we present a scalable in-situ thermal evaporation technique for synthesizing series of Bi,In,and Sn nanofilms on carbon felt(CF)substrates with a high-aspect-ratio *** resulting main-group metal nanofilms exhibit a homogeneously distributed and highly exposed catalyst surface with ample active sites,thereby promoting mass transport and ad-/desorption of reaction *** from the unique fractal morphology,the Bi nanofilms deposited on CF exhibit optimal catalytic activities for CO_(2)electroreduction among the designed metal nanofilms electrodes,with the highest Faradaic efficiency of 96.9%for formate production at−1.3 V *** hydrogen electrode(RHE)in *** an industrially relevant current density of 221.4 mA·cm−2 in flow cells,the Bi nanofilms retain a high Faradaic efficiency of 81.7%at−1.1 V(***)and a good long-term stability for formate ***,a techno-economic analysis(TEA)model shows the potential commercial viability of electrocatalytic CO_(2)conversion into formate using the Bi nanofilms *** results offer a green and convenient approach for in-situ fabrication of stable and inexpensive thin-film catalysts with a fractal structure applicable to various industrial settings.

关键词： CO_(2)electroreduction non-noble metal nanofilms flow cells efficiency and selectivity techno-economic analysis

Performance enhancement and active sites identification of Cu-Cd bimetallic oxide derived catalysts for electrochemical CO_(2) reduction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第4期91卷 50-58页

作者： Cai Wang Xin Hu Bairong Chen Houan Ren Xiaoyu Wang Yilin Zhang Xinyu Chen Yuping Liu Qingxin Guan Wei Li state key laboratory of Elemento-Organic chemistry Key Laboratory of Adv.Energy Mater.Chemistry(Ministry of Education)College of ChemistryNankai UniversityTianjin 300071China

The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great ***-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of ***,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 ***,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such *** results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.

关键词： CO_(2)reduction Cu-Cd bimetallic Real active sites CO production

Micelle-directed self-assembly of single-crystal-like mesoporous stoichiometric oxides for high-performance lithium storage

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第4期11卷 195-205页

作者： Yanhua Wan Changyao Wang Xingmiao Zhang Yang Yin Mengmeng Liu Bing Ma Linlin Duan Yuzhu Ma Wei Zhang Changlin Zheng Dongliang Chao Fei Wang Yongyao Xia Wei Li Department of chemistry Laboratory of Advanced Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials State Key Laboratory of Molecular Engineering of Polymers College of Chemistry and Materials ScienceFudan University state key laboratory of Surface Physics and Department of Physics Fudan University

Due to their uncontrollable assembly and crystallization process,the synthesis of mesoporous metal oxide single crystals remains a formidable ***,we report the synthesis of single-crystal-like mesoporous Li2TiSiO5by using soft micelles as *** key lies in the atomic-scale self-assembly and step-crystallization processes,which ensure the formation of single-crystal-like mesoporous Li2TiSiO5microparticles via an oriented attachment growth mechanism under the confinement of an in-situ formed carbon *** mesoporous Li2TiSiO5anode achieves a superior rate capability(148 mAh g-1at5.0 A g-1) and outstanding long-term cycling stability(138 mAh g-1after 3000 cycles at 2.0 A g-1) for lithium storage as a result of the ultrafast Li+diffusion caused by penetrating mesochannels and nanosized crystal frameworks（5-10 nm）.In comparison,bulk Li2TiSiO5exhibits poor rate capability and cycle performance due to micron-scale diffusion *** method is very simple and reproducible,heralding a new way of designing and synthesizing mesoporous single crystals with controllable frameworks and chemical functionalities.

关键词： mesoporous materials micelles single-crystal-like Li2TiSiO5 lithium-ion batteries

Highly crystallization-induced emissive luminophores with mechanoluminescent features for two-photon harvesting fluorescence imaging and latent fingerprint identification

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第7期17卷 6475-6482页

作者： Jian Lu Juan Gao Rui-Xuan Qian Shuai-Hua Wang Fa-Kun Zheng Guo-Cong Guo Fujian Science and Technology Innovation laboratory for Optoelectronic Information of China Fuzhou 350108China state key laboratory of structural chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Fluorescence imaging can be employed in fields of medical treatment,astronomical exploration,and national defense *** fluorescence imaging often takes the single-photon techniques,which is vulnerable to background interference and ***,two-photon fluorescence imaging can achieve much higher-resolution fluorescence imaging for reducing scattering and deeper ***,by assembling the tetraphenylethylene backbones with nontoxic and non-noble K^(+)ions,compound 1([(Hdma)K(H_(2)ettc)]_(n),H_(4)ettc=4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxylic acid)))with the crystallization-induced emissions exhibited charming fluorescence imaging under two-photon excitation microscopy(TPEM).Besides,luminescent powders based on compound 1 can achieve high-resolution fingerprint recognition,providing secure access control and identification for a novel authentication *** with the commercial fluorescent dyes coumarin-6,the as-synthesized compound 1 showed great solvent stability,indicating its durability against harsh ***,compound 1 shows mechanoluminescent properties for the perturbation of weak supramolecular interactions within ordered arrangements of the H_(2)ettc^(2−)*** novel compound has provided an important insight to the development of twophoton fluorescence imaging and advanced external-stimuli responsive materials.

关键词： crystallization-induced emission fluorescence imaging two-photon absorption fingerprint recognition mechanoluminescence

Lead-free hybrid two-dimensional double perovskite with switchable dielectric phase transition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第6期35卷 176-179页

作者： Tian Yang Yi Liu Lina Hua Yaoyao Chen Wuqian Guo Haojie Xu Xi Zeng Changhao Gao Wenjing Li Junhua Luo Zhihua Sun College of chemistry Fuzhou UniversityFuzhou 350108China state key laboratory of structural chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Molecular dielectric switches constitute a type of intelligent materials that are highly coveted for their distinctive advantages of switchable dielectric responses,lightweight,and mechanical ***(2D)hybrid perovskites have demonstrated excellent promise for assembling dielectric switches,in which the dynamic motions of organic moieties afford driving force to trigger switchable dielectric phase ***,we successfully assembled a new lead-free hybrid double perovskite,(CHA)4Cu Bi Br8(1,CHA=cyclohexylammonium),adopting a typical 2D structural motif,which shows dielectric anisotropy and bistable behaviors during the reversible phase transition near T_(c)=378 K(the Curie temperature).That is,its dielectric constants could be switched and tuned between high-dielectric and low-dielectric *** analyses reveal that the ordered-disordered transformation of the organic CHA+moiety and distortion of inorganic framework account for its phase *** result will stimulate further exploration of molecular dielectric switches in this 2D environmentally friendly family.

关键词： Dielectric switch Lead-free Double perovskite Phase transition Symmetry breaking

Reduction of dinitrogen to ammonia on doped three-atom clusters Nb_(2)M(M=Sc to Cu & Y to Ag)

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 3810-3818页

作者： Ran Cheng Chao-Nan Cui Zhi-Xun Luo Beijing National laboratory for Molecular Science(BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Science University of Chinese Academy of SciencesBeijing 100049China

Catalytic reduction of dinitrogen to ammonia under mild conditions remains an attractive topic for the purpose of lowering energy ***-atom metal clusters have been proved an ideal model to explore highly efficient catalysts taking advantage of unique geometric/electronic structures and cooperative active *** a study of N2 activation and reduction on seventeen bimetallic Nb_2M(M=Sc to Cu,and Y to Ag) clusters was *** key processes for ammonia fixation(namely nitrogen activation,hydrogenation,and ammonia desorption) are fully studied,and three preferred systems(Nb_2Ni,Nb_2Rh and Nb_2Pd) are highlighted with outstanding catalytic *** d-σ and d-π~* orbital hybridizations between these metal clusters and N_(2) were demonstrated and the internal association with the N≡N bond activation was *** examining the ammonia synthesis on four chosen Nb_(2)M clusters(M=Fe,Ni,Rh and Pd),it can be elucidated that the distal pathway is more favorable than the alternative pathway in these *** work not only clarifies the N_(2) reduction on the bimetallic Nb_(2)M clusters,but also guides efficient bimetallic catalyst design.

关键词： Three-atom cluster catalysis Three-criteria strategy Nitrogen fixation Ammonia synthesis Theoretical calculations

Topology Optimization of Metamaterial Microstructures for Negative Poisson’s Ratio under Large Deformation Using a Gradient-Free Method

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第5期139卷 2001-2026页

作者： Weida Wu Yiqiang Wang Zhonghao Gao Pai Liu state key laboratory of structural Analysis for Industrial Equipment Dalian University of TechnologyDalian116024China

Negative Poisson’s ratio(NPR)metamaterials are attractive for their unique mechanical behaviors and potential applications in deformation control and energy ***,when subjected to significant stretching,NPR metamaterials designed under small strain assumption may experience a rapid degradation in NPR *** address this issue,this study aims to design metamaterials maintaining a targeted NPR under large deformation by taking advantage of the geometry nonlinearity mechanism.A representative periodic unit cell is modeled considering geometry nonlinearity,and its topology is designed using a gradient-free *** unit cell microstructural topologies are described with the material-field series-expansion(MFSE)*** MFSE method assumes spatial correlation of the material distribution,which greatly reduces the number of required design *** conveniently design metamaterials with desired NPR under large deformation,we propose a two-stage gradient-free metamaterial topology optimization method,which fully takes advantage of the dimension reduction benefits of the MFSE method and the Kriging surrogate model ***,we use homogenization to find a preliminary NPR design under a small deformation *** the second stage,we begin with this preliminary design and minimize deviations in NPR from a targeted value under large *** this strategy and solution technique,we successfully obtain a group of NPR metamaterials that can sustain different desired NPRs in the range of[−0.8,−0.1]under uniaxial stretching up to 20% ***,typical microstructure designs are fabricated and tested through *** experimental results show good consistency with our numerical results,demonstrating the effectiveness of the present gradientfree NPR metamaterial design strategy.

关键词： Topology optimization microstructural design negative Poisson’s ratio large deformation