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Single-atom catalysts: controlled synthesis and dynamic mechanism in electrochemical oxygen evolution substitution reactions

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Rare Metals 2024年第10期43卷 4903-4920页

作者： Qin Zhao Rong gan Yi-Ling Ran Quan-Lei Ma Wen-Wen Chen Yue-Xin Guo yan Zhang Ding-Sheng Wang School of Chemistry Southwest Jiaotong University School of Life Science and Engineering Southwest Jiaotong University Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua University

Single-atom catalysts(SACs) have attracted much attention in the field of electrocatalysis due to their100% atomic utilization efficiency, clear active center and adjustable support. The application of SACs to anodic oxygen evolution substitution reactions with high conversion efficiency and selectivity is undoubtedly ***, a full understanding of the interactions between metal single-atom active sites and supports, and an in-depth understanding of the active centers and catalytic mechanisms of SACs in the electro-oxidation of small molecules are the keys to the development of high-performance catalysts. This review focuses on the synthesis of different support SACs and the interactions between single atoms and supports at the inter-face, and introduces the reaction mechanism of SACs in the electro-oxidation of different small-molecule substrates, such as ethanol, urea and hydrazine, with the aim of providing insights and ideas for the design of more efficient and ideal catalysts. Finally, we discuss the current challenges and future opportunities in the field.

关键词： Synthesis (chemical)

Structure regulating of metal clusters in carbonized metallic organic frameworks for high-efficient microwave absorption via tuning interaction strength between metals and ligands

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Nano Research 2024年第3期17卷 1699-1709页

作者： chang Sun Kun-yan Zhao Ming-Lu Huang Cheng-Long Luo Xu-Dong Chen Ming Wang School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function ManufacturingSouthwest UniversityChongqing 400715China Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory(Rongjiang Laboratory) Jieyang 515200China

Carbonized metallic organic frameworks(CMOF)have been attracting attention in microwave absorption(MA)research area because of their diverse structures,tunable compositions,and rich ***,structure regulation on metal clusters in CMOF is achieved by tuning the interaction strength between metals and ligands to enhance microwave absorption *** to relatively weak interaction among copper cations and ligands,copper nanoclusters(CuNC)can be uniformly formed and embedded within the cobalt/zinc(Co/Zn)***,copper cations are added to the Co/Zn bimetallic zeolitic imidazolate frameworks(ZIFs).Secondly,the CMOF composite particles with CuNCs(CuNCs/CoZn-CMOF)were developed by a pyrolysis *** CuNCs/CoZn-CMOF with an appropriate amount of CuNCs can harmonize both dielectric and magnetic *** a result,the minimum reflection loss(RLmin)reaches–45.1 dB at a matching thickness of 2.30 mm and the effective absorption bandwidth(EAB)is 8.80 GHz at a thickness of 3.10 *** broadband response to electromagnetic waves is attributed to interfacial polarization at CuNCs surface and heterogeneous interfaces,impedance matching and multiple scattering of electromagnetic *** study provides a feasible method to develop CMOF microwave absorption materials with high EAB values.

关键词： heterogeneous interface carbonized metallic organic frameworks microwave absorption interfacial polarization

SmEGY3 mediates H_(2)O_(2) production to enhance high-temperature stress tolerance by activating the expression of SmCSD1 in eggplant

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Horticultural Plant Journal 2024年第5期10卷 1247-1251页

作者： Renjian Liu Bingwei Yu Bingbing Shu Yuyuan Wang Yuwei gan Yonggui Liang Zhengkun Qiu Shuangshuang yan Bihao Cao Key Laboratory of Horticultural Crop Biology and Germplasm Innovation in South China Ministry of AgricultureCollege of HorticultureSouth China Agricultural UniversityGuangzhouGuangdong 510642China Guangdong Vegetable Engineering and Technology Research Center South China Agricultural UniversityGuangzhouGuangdong 510642China

High temperature(HT)has major effects on the growth and production of vegetable crops,including eggplant(Solanum melongena L.).Eggplant seedlings,flower organs,and fruits are affected by high temperature stress(HTS).Nonetheless,key HT response factors are rare in *** this study,we found that SmEGY3 was localized in chloroplasts and nuclei,and the expression was induced by *** confirmed that SmEGY3 played a positive role in regulating heat tolerance of plants by virus-induced gene silencing(VIGS)and overexpression *** to the control plants,the SmEGY3-silenced plants showed significantly decrease in the H_(2)O_(2) content and H_(2)O_(2)-mediated retrograde signalling genes expression while the SmEGY3-overexpressing plants displayed significantly increase.

关键词： crops fir organs

Evolution of the Mangrove Wetland since the Holocene:Current Progress and Future Perspectives

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Journal of Earth Science 2024年第5期35卷 1669-1678页

作者： Xueyan yan Xianzhong Ke Qinghua Li Yiqun gan Xianjun Xie Yamin Deng Geological Survey China University of GeosciencesWuhan 430074China Wuhan Center China Geological Survey(Central South China Innovation Center for Geosciences)Wuhan 430205China School of Environmental Studies China University of GeosciencesWuhan 430074China

Mangrove wetlands are among the four most productive tropical and subtropical *** are also a core component of the coastal blue carbon ecosystem,which is of great ecological significance to human beings,plants,animals,and the global carbon *** has been a global decrease in the distribution of mangrove forests,and their ecological function has gradually degenerated since the *** from coastal mangrove wetlands can provide records of climate change and human activities,and multiple proxies including palynology,leaf fossil,biomarkers,DNA,phytolith and stable isotopes,can be used to reconstruct the evolutionary stages of paleo-mangroves and to identify the effect of natural processes and human activities on the distribution and evolution of *** information can provide theoretical support for mangrove protection and for improving carbon sequestration *** paper summarizes and compares the multiple proxies for mangrove reconstruction,reviews progress in the study of natural succession of global mangroves since the Holocene,expands on the influence mechanisms of human activities on mangrove growth and development and uses past information to lay a foundation for a model to predict future mangrove development.

关键词： mangrove Holocene multiproxy sedimentary environment climate change environ-mental geology

Room-temperature ferromagnetism and piezoelectricity in metalfree 2D semiconductor crystalline carbon nitride

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Nano Research 2024年第6期17卷 5670-5679页

作者： Yong Wang Dingyi yang Wei Xu Yongjie Xu Yu Zhang Zixuan Cheng Yizhang Wu Xuetao gan Wei Zhong yan Liu Genquan Han Yue Hao Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory School of MicroelectronicsAcademy of Advanced Interdisciplinary ResearchXidian UniversityXi’an 710071China Emerging Device and Chip Laboratory Hangzhou Institute of TechnologyXidian UniversityHangzhou 311200China INRS Centre for Energy Materials and Telecommunications1650 Boul.Lionel BouletVarennesQC J3X 1P7Canada National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures and Jiangsu Provincial Key Laboratory for NanotechnologyNanjing UniversityNanjing 210093China School of Education Jiangsu Open UniversityNanjing 210036China Department of Physics Shaanxi University of Science and TechnologyXi’an 710021China Department of Applied Physical Sciences The University of North Carolina at Chapel HillChapel HillNC 27514USA Key Laboratory of Light Field Manipulation and Information Acquisition Ministry of Industry and Information Technologyand Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi'an 710129 China

Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic ***,the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems,which limits their practical applications due to a Curie temperature lower than room temperature(RT).Here,we report a high-crystallinity carbon nitride(CCN)material based on sp-electrons using a chemical vapor deposition *** exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane ***,we acquired clear evidences of ferromagnetic behavior at room *** structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites,which is primarily responsible for generating room-temperature ferromagnetism and *** a result,the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room *** addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices.

关键词： crystallinity carbon nitride room-temperature ferromagnetism piezoelectricity magnetic force microscopy density functional theory(DFT)calculations

Comprehensive evaluations of heat transfer performance with conjugate heat dissipation effect in high-speed rotating free-disk modeling of aero-engines

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Fundamental Research 2024年第3期4卷 611-623页

作者： Aqiang Lin Gaowen Liu Ran chang yan Chen Qing Feng School of Power and Energy Northwestern Polytechnical UniversityXi'an 710129China Shaanxi Key Laboratory of Thermal Science in Aero-engine System Northwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwester

Thermal boundary conditions of the turbine disk cavity system are of great importance in the design of secondary air systems in *** study aims to investigate the complex heat transfer mechanisms of a rotating turbine disk under high-speed conditions.A high-speed rotating free-disk model with Dorfman empirical solutions is developed to evaluate the heat transfer performance considering various ***,the influence of compressibility,variable properties,and heat dissipation is determined using theoretical and numerical *** particular,a novel combined solution method is proposed to simplify the complex heat transfer *** results indicate that the heat transfer performance of a free disk is primarily influenced by the rotating Mach number,rotating Reynolds number,Rossby number,and wall temperature *** heat transfer temperature and Nusselt number of the free disk are strongly correlated with the rotating Mach number and rotating Reynolds *** reveals that heat dissipation is a critical factor affecting the accurate evaluation of the heat transfer performance of the turbine ***,the combined solution method can serve as a reference for future investigations of flow and heat transfer in high-speed rotating turbine disk cavity systems in aero-engines.

关键词： Aero-engine Rotating turbine disk Dimensional analysis Compressibility Heat dissipation Dorfman empirical solution

Design of Ca-type todorokite catalysts with highly active for the selective reduction of NO_(x) by NH_(3) at low temperatures

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Journal of Environmental Sciences 2024年第4期138卷 697-708页

作者： Chuang chang Zidi yan Chunlei Zhang yanshuang Zhang Miao Jiang Luna Ruan Min Xiao Yunbo Yu Hong He School of Rare Earths University of Science and Technology of ChinaHefei 230026China ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NO_(x) by NH_(3)(NH_(3)-SCR)for the first *** with the Na-type manjiroite prepared by the same method,the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NO_(x) *** them,Mn8Ca4 catalyst exhibited the best NH_(3)-SCR performance,achieving 90%NO_(x) conversion within temperature range of 70-275℃ and having a high sulphur *** to the Na-type manjiroite sample,Ca-type todorokite catalysts possessed an increased size of tunnel,resulting in a larger specific surface *** increased the amounts of Ca doping,the Na content in Ca-type todorokite catalysts significantly decreased,providing larger amounts of Bronsted acid sites for NH_(3) adsorption to produce NH_(4)^(+).The NH_(4)^(+)species were highly active for reaction with NO+O_(2),playing a determining role in NH_(3)-SCR process at low ***,larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite,promoting the oxidation of NO and fast SCR *** the Ca-type todorokite catalysts,furthermore,nitrates produced during the flow of NO+O_(2),were more active for reaction with NH_(3) than that over Na-type manjiroite,benefiting the occurrence of NH_(3)-SCR *** study provides novel insights into the design of NH_(3)-SCR catalysts with high performance.

关键词： NO_(x) NH_(3)-SCR Mn-based oxides Ca-type todorokite Bronsted acid sites

Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

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China Ocean Engineering 2024年第1期38卷 29-41页

作者： LI yan-wei LIU Xiu-quan WANG Jin-long CHEN Guo-ming chang Yuan-jiang SHENG Lei-xiang Centre for Offshore Engineering and Safety Technology China University of PetroleumQingdao 266580China National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China China CNOOC Research Institute Co. Ltd.Beijing 100028China

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of *** approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex *** accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβ*** analysis program is also developed in MATLAB for dynamic *** simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation *** bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and *** platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

关键词： deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method

Rhodium-catalyzed enantioselective in situ C(sp^(3))-H heteroarylation by a desymmetrization approach

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Chinese Chemical Letters 2024年第10期35卷 218-222页

作者： Yujia Shi yan Qiao Pengfei Xie Miaomiao Tian Xingwei Li Junbiao chang Bingxian Liu State Key Laboratory of Antiviral Drugs NMPA Key Laboratory for Research and Evaluation of Innovative DrugSchool of Chemistry and Chemical EngineeringHenan Normal UniversityPingyuan LaboratoryXinxiang 453007China Department of Pathophysiology School of Basic Medical SciencesZhengzhou UniversityZhengzhou 450001China

A rhodium-catalyzed desymmetrization reaction for enantioselective methyl C-H arylation is achieved by utilizing an in situ arylating reagent via nucleophilic cyclization of o-aminoaryl *** reaction results in chiral indoles containing all-carbon quaternary stereocenters under atmospheric conditions,with a wide range of substrates exhibiting good enantioselectivity(44 examples).Mechnism and DFT studies show that the stereocontrol is reasonably achieved through the collaborative control of a large silicon substituted chiral ligand and C-H···π,LP···πinteractions between aryl rings of the carboxylate group and the *** experiments demonstrate that Rh-aryl bond formation via in situ nucleophilic cyclization is more critical for reaction efficiency than via C-H activation of the nucleophilic cyclization byproduct.

关键词： Heteroarylation C(sp^(3))-H activation Enantioselective Desymmetrization πInteractions