The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain ...The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain novel and valuable chemicals.The electrochemical synthesis of N-containing organic chemicals in electrocatalytic CO_(2) reduction via introducing N sources is an effective strategy to expand the product scope,since chemicals con-taining C–N bonds(e.g.amides and amines)are important reactants/products for medicine,agriculture and in-dustry.This article focuses on the research progress of C–N coupling from CO_(2) and inorganic nitrogenous species in aqueous solution.Firstly,the reaction pathways related to the reaction intermediates for urea,formamide,acetamide,methylamine and ethylamine are highlighted.Then,the electrocatalytic performance of different catalysts for these several N-containing products are summarized and classified.Finally,the challenges and op-portunities are analyzed,aiming to provide general insights into future research directions for electrocatalytic C–N coupling.展开更多
Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)...Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.展开更多
Urea is extensively used in agriculture and chemical industry,and it is produced on an industrial scale from CO_(2)and Haber-Bosch NH_(3)under relatively high temperature and high pressure conditions,which demands hig...Urea is extensively used in agriculture and chemical industry,and it is produced on an industrial scale from CO_(2)and Haber-Bosch NH_(3)under relatively high temperature and high pressure conditions,which demands high energy input and generates masses of carbon footprint.The conversion of CO_(2)and N sources(such as NO_(2)^(−),NO_(3)^(−),and N_(2))through electrocatalytic reactions under ambient conditions is a promising alternative to realize efficient urea synthesis.Of note,the design of electrocatalyst is one of the key factors that can improve the efficiency and selectivity of C-N coupling reactions.Defect engineer-ing is an intriguing strategy for regulating the electronic structure and charge density of electrocatalysts,which endows electrocatalysts with excellent physicochemical properties and optimized adsorption en-ergy of the reaction intermediates to reduce the kinetic barriers.In this minireview,recent advances of defect engineered electrocatalysts in urea electrosynthesis from CO_(2)and various N reactants are firstly introduced.Mechanistic discussions of C-N coupling in these advances are presented,with the aim of directing future investigations on improving the urea yield.Finally,the prospects and challenges of de-fect engineered electrocatalysts for urea synthesis are discussed.This overview is expected to provide in-depth understanding of structure-reactivity relationship and shed light on future electrocatalytic C-N coupling reactions.展开更多
Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of...Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.展开更多
Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized ...Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized and subse- quently used as macroinitiators for atom transfer radial polymerization (ATRP) of n-butyl acrylate (n-BA) and ethyl acrylate (EA). Both the polymerization processes were controlled and the polymers were characterized by 1H NMR, gel permeation chromatography (GPC) and thermal properties, which confirmed the successful synthesis of all the poly-mers. The microphase separated behaviors of the poly (4-butyltriarylamine)-block-poly (butyl acrylate) (PBTPA-b-PBA) were examined by AFM in the film showing phase separation structures for all the polymers. The photorefractive property of the composite based on PBTPA-b-PBA block copolymer was evaluated by two-beam coupling experiment. A relative high gain coefficient of 42.7 cm?1 was obtained at the electric field of 31 V/?m.展开更多
Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environme...Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of urea.Electrocatalysis provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond.展开更多
Urea,a critical nitrogen-based feedstock predominantly employed in fertilizer production,can be synthesized via electrocatalytic C-N coupling,which provides an efficient route for efficient nitrogen and carbon fixatio...Urea,a critical nitrogen-based feedstock predominantly employed in fertilizer production,can be synthesized via electrocatalytic C-N coupling,which provides an efficient route for efficient nitrogen and carbon fixation under mild conditions.Nonetheless,electrocatalytic urea synthesis is hindered by intricate intermediate pathways and competing side reactions,leading to low urea selectivity and yield.Therefore,improving the efficiency of electrocatalytic urea synthesis requires efficient catalysts.This review presents an overview of urea detection methodologies,elucidates the C-N coupling mechanisms,and explores catalyst design strategies.Accurate detection of urea detection is particularly vital in low-yield systems;thus,we analyze the advantages and limitations of several detection techniques.Additionally,we investigate the fundamental reaction mechanisms that allow reduction of CO_(2)and various nitrogen species to be reduced simultaneously.A detailed examination of catalyst design strategies aimed at improving electrocatalytic urea production,including heterostructure,atomically dispersed structures,and vacancy engineering,is provided.Finally,we address the emerging challenges that must be tackled as the technology progresses.展开更多
The conversion and utilization of carbon dioxide(CO_(2))is one of the central topics in the energy and environmental research community.The development of electrocatalytic CO_(2) reduction technology is expected to br...The conversion and utilization of carbon dioxide(CO_(2))is one of the central topics in the energy and environmental research community.The development of electrocatalytic CO_(2) reduction technology is expected to bring more economic and environmental benefits to the carbon-neutral policy.Although researchers have conducted extensive and in-depth studies on the electrocatalytic CO_(2) reduction to derive diverse carbonaceous products such as C_(1) and C_(2+),the introduction of inorganic nitrogenous molecules in the electrocatalytic CO_(2) reduction can further expand the production of more valuable C-N bondcontaining chemicals,such as amides,amines,and urea.This review focuses on the research progress in the electrochemical C-N coupling of CO_(2) with diverse nitrogenous small molecules(NH_(3),N_(2),NO,NO_(2)^(-),and NO_(3)^(-))in aqueous solution.The C-N coupling mechanisms and electrocatalytic performance of catalysts towards different products have been discussed in depth from both computational and experimental aspects.On this basis,the research directions and prospects in this field are proposed,aiming to provide valuable insights into future research on electrocatalytic C-N coupling.展开更多
Electrochemical urea synthesis from CO_(2)and NO(EUCN)offers a promising route for sustainable urea production,whereas it still suffers from low C-N coupling efficiency and poor selectivity.Herein,atomically dispersed...Electrochemical urea synthesis from CO_(2)and NO(EUCN)offers a promising route for sustainable urea production,whereas it still suffers from low C-N coupling efficiency and poor selectivity.Herein,atomically dispersed p-block Bi catalyst is explored for highly active and selective EUCN.Theoretical calculations and in situ spectroscopic analyses reveal a unique*CO-mediated C-N coupling mechanism,where isolated Bi sites facilitate CO_(2)reduction for*CO formation and enrichment,while*CO-enriched microenvironment boosts subsequent C-N coupling of*CO and*NO to*CONO,a critical C-N intermediate for urea generation,while simultaneously suppressing the competing side reactions.Notably,by pairing cathodic EUCN with anodic glycerol oxidation in a membrane electrode assembly electrolyzer,we achieve a record-high performance with urea yield rate of 86.5 mmol·h^(-1)·g^(-1)and Faradaic efficiency of 52.1%,as well as the outstanding stability for over 200 h electrolysis.展开更多
The electrocatalytic C-N coupling reaction as a green synthesis approach for C-N bond synthesis via electrochemical processes with catalytic assistance.However,inefficient reactant adsorption onto the catalyst surface...The electrocatalytic C-N coupling reaction as a green synthesis approach for C-N bond synthesis via electrochemical processes with catalytic assistance.However,inefficient reactant adsorption onto the catalyst surface,competing side reactions,and the complexity and diversity of reaction pathways hinder its widespread application.Atomically dispersed catalysts(ADCs),as an emerging class of catalytic materials,possess precisely defined active sites,high catalytic activity,and enhanced selectivity,thereby enabling efficient electrocatalytic C-N coupling to address these challenges.This review discusses current reaction pathways for converting small molecules(CO_(2)as the carbon source,N_(2),NO_(2)^(-),NO_(3)^(-)as the nitrogen source)into high-value organic nitrogen compounds(urea,amides,oximes,and amino acids)utilizing ADCs.It specifically focuses on the critical steps within electrocatalytic C-N coupling facilitated by these catalysts,encompassing reactant adsorption,transformation and selective hydrogenation of C-/N-intermediates,and the C-N coupling reaction itself.Based on these key steps,design principles for ADCs are proposed.Finally,the synthesis strategies for ADCs-vacancy engineering,confinement strategies,and alloying-are examined,alongside the mechanisms by which they enhance catalytic activity and selectivity.展开更多
Photocatalytic urea production from nitrogen(N_(2))and carbon dioxide(CO_(2))is a sustainable and ecofriendly alternative to the Bosch-Meiser route.However,it remains a significant challenge in developing highly effic...Photocatalytic urea production from nitrogen(N_(2))and carbon dioxide(CO_(2))is a sustainable and ecofriendly alternative to the Bosch-Meiser route.However,it remains a significant challenge in developing highly efficient photocatalysts for enhancing C-N coupling to high-yield urea synthesis.Herein,we propose a multi-site photocatalyst concept to address the concern of low yield by simultaneously improving photogenerated carrier separation and reactant activation.As a proof of concept,a well-defined multisite photocatalyst,Ru nanoparticles and Cu single atoms decorated CeO_(2)nanorods(Ru-Cu/CeO_(2)),is developed for efficient urea production.The incorporation of Ru and Cu sites is crucial not only to generate high-density photogenerated electrons,but also to facilitate N_(2)and CO_(2)adsorption and conversion.The in situ formed local nitrogen-rich area at Ru sites increases the encounter possibility with the carbon-containing species generated from Cu sites,substantially promoting C-N coupling.The Ru-Cu/CeO_(2)photocatalyst exhibits an impressive urea yield rate of 16.7μmol g^(-1)h^(-1),which ranks among the best performance reported to date.This work emphasizes the importance of multi-site catalyst design concept in guaranteeing rapid C-N coupling in photocatalytic urea synthesis and beyond.展开更多
Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural...This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural revitalization.By examining panel data from 30 Chinese provinces,autonomous regions,and municipalities between 2011 and 2022,the research constructs a weight-based evaluation system that integrates subjective and objective methods and a coupling coordination model to reveal its dynamic evolution patterns.Key findings indicate that digital economy–agriculture integration and rural revitalization achieve cross-coupling through critical activities.The impact of digital-agriculture integration on advancing rural revitalization lags by 2–3 years.Although the coupling development degree between the two systems continues to improve,it remains at the stage of primary coordination.Regional disparities are significant,showing a gradient pattern of“high degree of coupling development in the east and low degree of coupling development in the west.”展开更多
Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to ...Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to the unique functional attributes and interaction patterns inherent to different layers.This paper addresses the critical question of whether structural information from a known layer can be used to reconstruct the unknown intralayer structure of a target layer within general weighted output-coupling multilayer networks.Building upon the generalized synchronization principle,we propose an innovative reconstruction method that incorporates two essential components in the design of structure observers,the cross-layer coupling modulator and the structural divergence term.A key advantage of the proposed reconstruction method lies in its flexibility to freely designate both the unknown target layer and the known reference layer from the general weighted output-coupling multilayer network.The reduced dependency on full-state observability enables more deployment in engineering applications with partial measurements.Numerical simulations are conducted to validate the effectiveness of the proposed structure reconstruction method.展开更多
The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segmen...The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).展开更多
The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Rel...The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.展开更多
Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling ...Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.展开更多
This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,Calcu...This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,CalculiX,and preCICE to simulate fluid-particle-structure interactions with large deformations.Mesh motion in the fluid field is handled using the radial basis function(RBF)method.The particle phase is modeled by MPPIC,where fluid-particle interaction is described through momentum exchange,and inter-particle collisions are characterized by collision stress.The structural field is solved by nonlinear FEM to capture large deformations induced by geometric nonlinearity.Coupling among fields is realized through a partitioned,parallel,and non-intrusive iterative strategy,ensuring stable transfer and convergence of interface forces and displacements.Notably,the influence of particles on the structure is not direct but mediated by the fluid,while structural motion directly affects particle dynamics.The results demonstrate that the proposed approach effectively captures multiphysics interaction processes and provides a valuable reference for numerical modeling of coupled fluid-particle-structure systems.展开更多
In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally r...In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.展开更多
With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railg...With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railgun systems.Traditional aluminum alloy armatures often suffer from severe ablation,deformation,and uneven current distribution under high pulsed currents,which limit their performance and service life.To address these challenges,this study employs the Johnson–Cook constitutive model and the finite element method to develop armature models of aluminum matrix composites with varying heterogeneous graphene volume fractions.The temperature,stress,and strain of the armatures during operation were analyzed to investigate the effects of different graphene volume fractions on the deformation and damage behavior of aluminum matrix composite armatures under the multi-field coupling of electromagnetic,thermal,and structural interactions.The results indicate that,compared to the 6061 aluminum alloy matrix,the graphene-reinforced aluminum matrix composite armature significantly suppresses ablation damage at the tail and throat edges.The incorporation of graphene notably reduces the temperature rise during the armature emission process,increases the muzzle velocity under identical current excitation,and mitigates directional deformation of the armature.The 1 wt.% graphene-reinforced aluminum matrix composite armature demonstrates better agreement with experimental results at a strain rate of 2000 s^(-1),while simultaneously improving stress-strain response,reducing temperature rise,and improving velocity performance.展开更多
基金financially supported by National Natural Science Foundation of China(22072051,22122202,21972051).
文摘The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain novel and valuable chemicals.The electrochemical synthesis of N-containing organic chemicals in electrocatalytic CO_(2) reduction via introducing N sources is an effective strategy to expand the product scope,since chemicals con-taining C–N bonds(e.g.amides and amines)are important reactants/products for medicine,agriculture and in-dustry.This article focuses on the research progress of C–N coupling from CO_(2) and inorganic nitrogenous species in aqueous solution.Firstly,the reaction pathways related to the reaction intermediates for urea,formamide,acetamide,methylamine and ethylamine are highlighted.Then,the electrocatalytic performance of different catalysts for these several N-containing products are summarized and classified.Finally,the challenges and op-portunities are analyzed,aiming to provide general insights into future research directions for electrocatalytic C–N coupling.
基金supported by the Research Grants Council(26206115,16304821 and 16309418)the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(SMSEGL20SC01)+2 种基金the Innovation and Technology Commission(grant no.ITC-CNERC14EG03)of the Hong Kong Special Administrative Regionthe Hong Kong Postdoctoral Fellowship Scheme(HKUST PDFS2021-4S12 and HKUST PDFS2021-6S08)the support from the Shenzhen fundamental research funding(JCYJ20210324115809026,20200925154115001,JCYJ20200109141216566)。
文摘Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.
基金supported by the National Natural Science Foundation of China(Nos.22278094,22209029)Outstanding Youth Project of Guangdong Natural Science Foundation(No.2020B1515020028)+2 种基金Guangdong Natural Science Foundation(No.2022A1515011775)University Innovation Team Scientific Research Project of Guangzhou Education Bureau(No.202235246)China Postdoctoral Science Foundation(No.2023M730760).
文摘Urea is extensively used in agriculture and chemical industry,and it is produced on an industrial scale from CO_(2)and Haber-Bosch NH_(3)under relatively high temperature and high pressure conditions,which demands high energy input and generates masses of carbon footprint.The conversion of CO_(2)and N sources(such as NO_(2)^(−),NO_(3)^(−),and N_(2))through electrocatalytic reactions under ambient conditions is a promising alternative to realize efficient urea synthesis.Of note,the design of electrocatalyst is one of the key factors that can improve the efficiency and selectivity of C-N coupling reactions.Defect engineer-ing is an intriguing strategy for regulating the electronic structure and charge density of electrocatalysts,which endows electrocatalysts with excellent physicochemical properties and optimized adsorption en-ergy of the reaction intermediates to reduce the kinetic barriers.In this minireview,recent advances of defect engineered electrocatalysts in urea electrosynthesis from CO_(2)and various N reactants are firstly introduced.Mechanistic discussions of C-N coupling in these advances are presented,with the aim of directing future investigations on improving the urea yield.Finally,the prospects and challenges of de-fect engineered electrocatalysts for urea synthesis are discussed.This overview is expected to provide in-depth understanding of structure-reactivity relationship and shed light on future electrocatalytic C-N coupling reactions.
基金support from the Tangshan Talent Funding Project(Grant No.A202202007)National Natural Science Foundation of China(Grant Nos.22102136 and 21703065)+2 种基金Natural Science Foundation of Hebei Province(Grant Nos.B2018209267 and E2022209039)Natural Science Foundation of Hubei Province(Grant No.2022CFB1001)Department of Education of Hubei Province(Grant No.Q20221701).
文摘Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.
文摘Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized and subse- quently used as macroinitiators for atom transfer radial polymerization (ATRP) of n-butyl acrylate (n-BA) and ethyl acrylate (EA). Both the polymerization processes were controlled and the polymers were characterized by 1H NMR, gel permeation chromatography (GPC) and thermal properties, which confirmed the successful synthesis of all the poly-mers. The microphase separated behaviors of the poly (4-butyltriarylamine)-block-poly (butyl acrylate) (PBTPA-b-PBA) were examined by AFM in the film showing phase separation structures for all the polymers. The photorefractive property of the composite based on PBTPA-b-PBA block copolymer was evaluated by two-beam coupling experiment. A relative high gain coefficient of 42.7 cm?1 was obtained at the electric field of 31 V/?m.
基金National Natural Science Foundation of China (No. 22202065, 22075092 and U21A20500)。
文摘Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of urea.Electrocatalysis provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52273058 and 52073124)the Natural Science Foundation of Jiangsu Province(No.BK2022030167)the Fundamental Research Funds for the Central Universities.
文摘Urea,a critical nitrogen-based feedstock predominantly employed in fertilizer production,can be synthesized via electrocatalytic C-N coupling,which provides an efficient route for efficient nitrogen and carbon fixation under mild conditions.Nonetheless,electrocatalytic urea synthesis is hindered by intricate intermediate pathways and competing side reactions,leading to low urea selectivity and yield.Therefore,improving the efficiency of electrocatalytic urea synthesis requires efficient catalysts.This review presents an overview of urea detection methodologies,elucidates the C-N coupling mechanisms,and explores catalyst design strategies.Accurate detection of urea detection is particularly vital in low-yield systems;thus,we analyze the advantages and limitations of several detection techniques.Additionally,we investigate the fundamental reaction mechanisms that allow reduction of CO_(2)and various nitrogen species to be reduced simultaneously.A detailed examination of catalyst design strategies aimed at improving electrocatalytic urea production,including heterostructure,atomically dispersed structures,and vacancy engineering,is provided.Finally,we address the emerging challenges that must be tackled as the technology progresses.
基金supported by the National Key Research and Development Program of China(2021YFA1500702,2022YFE0108000,2023YFA1509103)the National Natural Science Foundation of China(22425207,22321002)+1 种基金the DICP(DICP I202314,DICP I202425)support from the China Postdoctoral Science Foundation(2024M753159).
文摘The conversion and utilization of carbon dioxide(CO_(2))is one of the central topics in the energy and environmental research community.The development of electrocatalytic CO_(2) reduction technology is expected to bring more economic and environmental benefits to the carbon-neutral policy.Although researchers have conducted extensive and in-depth studies on the electrocatalytic CO_(2) reduction to derive diverse carbonaceous products such as C_(1) and C_(2+),the introduction of inorganic nitrogenous molecules in the electrocatalytic CO_(2) reduction can further expand the production of more valuable C-N bondcontaining chemicals,such as amides,amines,and urea.This review focuses on the research progress in the electrochemical C-N coupling of CO_(2) with diverse nitrogenous small molecules(NH_(3),N_(2),NO,NO_(2)^(-),and NO_(3)^(-))in aqueous solution.The C-N coupling mechanisms and electrocatalytic performance of catalysts towards different products have been discussed in depth from both computational and experimental aspects.On this basis,the research directions and prospects in this field are proposed,aiming to provide valuable insights into future research on electrocatalytic C-N coupling.
基金supported by the National Natural Science Foundation of China(No.52561042)Gansu Province Key Talent Project(2025RCXM008).
文摘Electrochemical urea synthesis from CO_(2)and NO(EUCN)offers a promising route for sustainable urea production,whereas it still suffers from low C-N coupling efficiency and poor selectivity.Herein,atomically dispersed p-block Bi catalyst is explored for highly active and selective EUCN.Theoretical calculations and in situ spectroscopic analyses reveal a unique*CO-mediated C-N coupling mechanism,where isolated Bi sites facilitate CO_(2)reduction for*CO formation and enrichment,while*CO-enriched microenvironment boosts subsequent C-N coupling of*CO and*NO to*CONO,a critical C-N intermediate for urea generation,while simultaneously suppressing the competing side reactions.Notably,by pairing cathodic EUCN with anodic glycerol oxidation in a membrane electrode assembly electrolyzer,we achieve a record-high performance with urea yield rate of 86.5 mmol·h^(-1)·g^(-1)and Faradaic efficiency of 52.1%,as well as the outstanding stability for over 200 h electrolysis.
基金supported by the National Natural Science Foundation of China(No.22375019)Postdoctoral Fellowship Program of CPSF under Grant Number GZC20252673.
文摘The electrocatalytic C-N coupling reaction as a green synthesis approach for C-N bond synthesis via electrochemical processes with catalytic assistance.However,inefficient reactant adsorption onto the catalyst surface,competing side reactions,and the complexity and diversity of reaction pathways hinder its widespread application.Atomically dispersed catalysts(ADCs),as an emerging class of catalytic materials,possess precisely defined active sites,high catalytic activity,and enhanced selectivity,thereby enabling efficient electrocatalytic C-N coupling to address these challenges.This review discusses current reaction pathways for converting small molecules(CO_(2)as the carbon source,N_(2),NO_(2)^(-),NO_(3)^(-)as the nitrogen source)into high-value organic nitrogen compounds(urea,amides,oximes,and amino acids)utilizing ADCs.It specifically focuses on the critical steps within electrocatalytic C-N coupling facilitated by these catalysts,encompassing reactant adsorption,transformation and selective hydrogenation of C-/N-intermediates,and the C-N coupling reaction itself.Based on these key steps,design principles for ADCs are proposed.Finally,the synthesis strategies for ADCs-vacancy engineering,confinement strategies,and alloying-are examined,alongside the mechanisms by which they enhance catalytic activity and selectivity.
基金support by the National Natural Science Foundation of China(12222508,12475325,and 22209061)the Youth Innovation Promotion Association CAS(2020454)+2 种基金the National Key R&D Program of China(2019YFA0405601 and2023YFA1506304)the Fundamental Research Funds for the Universities of Inner Mongolia Autonomous Region(JY20250030)the Start-up Fund for Senior Talents in Jiangsu University(21JDG060)。
文摘Photocatalytic urea production from nitrogen(N_(2))and carbon dioxide(CO_(2))is a sustainable and ecofriendly alternative to the Bosch-Meiser route.However,it remains a significant challenge in developing highly efficient photocatalysts for enhancing C-N coupling to high-yield urea synthesis.Herein,we propose a multi-site photocatalyst concept to address the concern of low yield by simultaneously improving photogenerated carrier separation and reactant activation.As a proof of concept,a well-defined multisite photocatalyst,Ru nanoparticles and Cu single atoms decorated CeO_(2)nanorods(Ru-Cu/CeO_(2)),is developed for efficient urea production.The incorporation of Ru and Cu sites is crucial not only to generate high-density photogenerated electrons,but also to facilitate N_(2)and CO_(2)adsorption and conversion.The in situ formed local nitrogen-rich area at Ru sites increases the encounter possibility with the carbon-containing species generated from Cu sites,substantially promoting C-N coupling.The Ru-Cu/CeO_(2)photocatalyst exhibits an impressive urea yield rate of 16.7μmol g^(-1)h^(-1),which ranks among the best performance reported to date.This work emphasizes the importance of multi-site catalyst design concept in guaranteeing rapid C-N coupling in photocatalytic urea synthesis and beyond.
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
基金Youth project under the National Social Science Foundation of China(15CJY054)key project in Philosophy and Social Sciences funded by the Chongqing Municipal Education Commission(22SKGH091)。
文摘This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural revitalization.By examining panel data from 30 Chinese provinces,autonomous regions,and municipalities between 2011 and 2022,the research constructs a weight-based evaluation system that integrates subjective and objective methods and a coupling coordination model to reveal its dynamic evolution patterns.Key findings indicate that digital economy–agriculture integration and rural revitalization achieve cross-coupling through critical activities.The impact of digital-agriculture integration on advancing rural revitalization lags by 2–3 years.Although the coupling development degree between the two systems continues to improve,it remains at the stage of primary coordination.Regional disparities are significant,showing a gradient pattern of“high degree of coupling development in the east and low degree of coupling development in the west.”
基金Project supported by the National Natural Science Foun-dation of China(Grant No.62373197)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(Grant No.23KJB120010)+1 种基金the Industry-University-Research Cooperation Project of Jiangsu Province,China(Grant No.BY20251038)the Cultivation and In-cubation Project of the College of Automation,Nanjing Uni-versity of Posts and Telecommunications.
文摘Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to the unique functional attributes and interaction patterns inherent to different layers.This paper addresses the critical question of whether structural information from a known layer can be used to reconstruct the unknown intralayer structure of a target layer within general weighted output-coupling multilayer networks.Building upon the generalized synchronization principle,we propose an innovative reconstruction method that incorporates two essential components in the design of structure observers,the cross-layer coupling modulator and the structural divergence term.A key advantage of the proposed reconstruction method lies in its flexibility to freely designate both the unknown target layer and the known reference layer from the general weighted output-coupling multilayer network.The reduced dependency on full-state observability enables more deployment in engineering applications with partial measurements.Numerical simulations are conducted to validate the effectiveness of the proposed structure reconstruction method.
基金supported by the National Natural Science Foundation of China(Grant Nos.22193032 and 32401033)the Research Fund of Wenzhou Institute,Chinese Academy of Sciences(Grant Nos.WIUCASQD2020009,WIUCASQD2023005,XSZD2024004,2021HZSY0061,and WIUCASICTP2022)。
文摘The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).
基金supported by the National Science and Tech-nology Major Project,China(No.J2019-II-0012-0032)。
文摘The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.
基金supported by the National Key Research and Development Program of China (MOST)(Grant No.2022YFA1402800)the Chinese Academy of Sciences (CAS) Presidents International Fellowship Initiative (PIFI)(Grant No.2025PG0006)+3 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos.51831012,12274437,and 52161160334)the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-084)the CAS Youth Interdisciplinary Teamthe China Postdoctoral Science Foundation (Grant No.2025M773402)。
文摘Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.
基金supported in part by the Mining Hydraulic Technology and Equipment Engineering Research Center,Liaoning Technical University,Fuxin,China(Grant No.MHTE23-R04)the Fundamental Research Funds for the Central Universities(ID N25BSS068).
文摘This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,CalculiX,and preCICE to simulate fluid-particle-structure interactions with large deformations.Mesh motion in the fluid field is handled using the radial basis function(RBF)method.The particle phase is modeled by MPPIC,where fluid-particle interaction is described through momentum exchange,and inter-particle collisions are characterized by collision stress.The structural field is solved by nonlinear FEM to capture large deformations induced by geometric nonlinearity.Coupling among fields is realized through a partitioned,parallel,and non-intrusive iterative strategy,ensuring stable transfer and convergence of interface forces and displacements.Notably,the influence of particles on the structure is not direct but mediated by the fluid,while structural motion directly affects particle dynamics.The results demonstrate that the proposed approach effectively captures multiphysics interaction processes and provides a valuable reference for numerical modeling of coupled fluid-particle-structure systems.
基金Project supported by the National Natural Science Foundation of China(No.12472062)。
文摘In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.
基金funded Basic Research Projects of Higher Education Institutions in Liaoning Province(JYTZD20230004)Future Industry Frontier Technology Project in Liaoning Province in 2025(2025JH2/101330141)Key Research and Development Program of Liaoning Province in 2025.
文摘With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railgun systems.Traditional aluminum alloy armatures often suffer from severe ablation,deformation,and uneven current distribution under high pulsed currents,which limit their performance and service life.To address these challenges,this study employs the Johnson–Cook constitutive model and the finite element method to develop armature models of aluminum matrix composites with varying heterogeneous graphene volume fractions.The temperature,stress,and strain of the armatures during operation were analyzed to investigate the effects of different graphene volume fractions on the deformation and damage behavior of aluminum matrix composite armatures under the multi-field coupling of electromagnetic,thermal,and structural interactions.The results indicate that,compared to the 6061 aluminum alloy matrix,the graphene-reinforced aluminum matrix composite armature significantly suppresses ablation damage at the tail and throat edges.The incorporation of graphene notably reduces the temperature rise during the armature emission process,increases the muzzle velocity under identical current excitation,and mitigates directional deformation of the armature.The 1 wt.% graphene-reinforced aluminum matrix composite armature demonstrates better agreement with experimental results at a strain rate of 2000 s^(-1),while simultaneously improving stress-strain response,reducing temperature rise,and improving velocity performance.
