Improving the atom utilization of metals and clarifying the M–M’interaction is both greatly significant in assembling high-performance ultra-light electromagnetic wave-absorbing materials.Herein,a high-temperature e...Improving the atom utilization of metals and clarifying the M–M’interaction is both greatly significant in assembling high-performance ultra-light electromagnetic wave-absorbing materials.Herein,a high-temperature explosion strategy has been successfully applied to assemble the hierarchical porous carbon sponge with Co–Fe decoration via the pyrolysis of the energetic metal organic framework.The as-constructed hybrid displays a superior reflection loss(RL)value of-57.7 d B and a specific RL value of-192 d B mg-1 mm-1 at 12.08 GHz with a layer thickness of 2.0 mm(loading of 15 wt%).The off-axis electron hologram characterizes the highly distributed numerous polarized nanodomain variable capacitors,demonstrating the dipole and interfacial polarization along the edges of the nanopores.More importantly,the X-ray absorption spectroscopy analysis verifies the mutual interaction between the metal cluster and carbon matrix and the electronic coupling responsible for the greatly improved electromagnetic wave absorption.展开更多
Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode ...Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode cannot match the capacitor-type cathode, restricting the development of LICs. Herein, hierarchical carbon framework(HCF) anode material composed of 0D carbon nanocage bridged with 2D graphene network are developed via a template-confined synthesis process. The HCF with nanocage structure reduces the Li^(+) transport path and benefits the rapid Li^(+) migration, while 2D graphene network can promote the electron interconnecting of carbon nanocages. In addition, the doped N atoms in HCF facilitate to the adsorption of ions and enhance the pseudo contribution, thus accelerate the kinetics of the anode. The HCF anode delivers high specific capacity, remarkable rate capability. The LIC pouch-cell based on HCF anode and active HCF(a-HCF) cathode can provide a high energy density of 162 Wh kg^(-1) and a superior power density of 15.8 kW kg^(-1), as well as a long cycling life exceeding 15,000cycles. This study demonstrates that the well-defined design of hierarchical carbon framework by incorporating 0D carbon nanocages and 2D graphene network is an effective strategy to promote LIC anode kinetics and hence boost the LIC electrochemical performance.展开更多
Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the...Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis method.The large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the material.Notably,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host material.The porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature pyrolysis.At the same time,they can also be used in various complex environments,such as acidic and basic environments.Ultimately,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 mm.After soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.展开更多
Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder ...Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder their practical applications.Herein,a metal oxyacid salts-confined pyrolysis strategy is proposed to construct hierarchical porous metal oxide@carbon(MO@C,MO=MoO_(2),V_(2)O_(5),WO_(3))composites for solving the aforementioned problems.A water-evaporation-induced self-assembly mechanism has been put forward for fabricating the MO@polyvinyl pyrrolidone(PVP)@SiO_(2)precursors.After the following pyrolysis and etching process,small MO nanoparticles can be successfully encapsulated in the hierarchical porous carbon framework.Profiting from the synergistic effect of MO nanoparticles and highly conductive carbon framework,MO@C composites show excellent electrochemical properties.For example,the as-obtained MoO_(2)@C composite exhibits a large discharge capacity(1513.7 mAh·g^(−1)at 0.1 A·g^(−1)),good rate ability(443.5 mAh·g^(−1)at 5.0 A·g^(−1)),supernal long-lived stability(669.1 mAh·g^(−1)after 1000 cycles at 1.0 A·g^(−1)).This work will inspire the design of novel anode materials for high-performance LIBs.展开更多
Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative partic...Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative particle swarm optimization(MHCHPSO)to optimize sensor deployment location and improve the coverage of WSN.MHCHPSO divides the population into three types topology:diversity topology for global exploration,fast convergence topology for local development,and collaboration topology for exploration and development.All topologies are optimized in parallel to overcome the precocious convergence of PSO.This paper compares with various heuristic algorithms at CEC 2013,CEC 2015,and CEC 2017.The experimental results show that MHCHPSO outperforms the comparison algorithms.In addition,MHCHPSO is applied to the WSN localization optimization,and the experimental results confirm the optimization ability of MHCHPSO in practical engineering problems.展开更多
Precise assembly of active component with sophisticated confinement in electrocatalyst are promising to increase the active site exposure for enhanced hydrogen evolution reaction(HER).Here,PCN-333 films with mesopores...Precise assembly of active component with sophisticated confinement in electrocatalyst are promising to increase the active site exposure for enhanced hydrogen evolution reaction(HER).Here,PCN-333 films with mesopores are firstly assembled on titanium carbide MXene with the assistance of atomic layer deposited oxide nanomembrane.With the whereafter pyrolysis process,the composite is converted to Ndoped porous carbon multi-layer containing Fe nanoparticles.The strong confinement of Fe active particle in carbon as well as great contact between metal and carbon effectively enhance active site exposure.Furthermore,this multi-layer porous structure provides high specific surface area and plentiful mesopores for electrolyte penetration.Due to the structural advantage,the composite can be well functioned in both acid and alkaline electrolytes with excellent HER performance,e.g.,low overpotential/Tafel slope.The present work may have great potential in developing high efficiency transition-metal based electrocatalysts.展开更多
The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is prop...The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs(NH-MOFs)with high crystallinity and excellent stability.This approach allows the morphology and porosity of MOFs to be fine tuned,thereby enabling the nanoscale crystal generation and a well-defined hierarchical system.The aqueous solution facilitates rapid nucleation kinetics,and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent(SDA)to guide the formation of hierarchical networks.The assynthesized NH-MOFs(NH-ZIF-67)were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of guest molecules,outperforming the parent microZIF-67.This study focuses on understanding the NH-MOF growth rules,which could allow tailor-designing NH-MOFs for various functions.展开更多
Exploring how food web complexity emerges and evolves in island ecosystems remains a major challenge in ecology.Food webs assembled from multiple islands are commonly recognized as highly complex trophic networks that...Exploring how food web complexity emerges and evolves in island ecosystems remains a major challenge in ecology.Food webs assembled from multiple islands are commonly recognized as highly complex trophic networks that are dynamic in both space and time.In the context of global climate change,it remains unclear whether food web complexity will decrease in a monotonic fashion when undergoing habitat destruction(e.g.,the inundation of islands due to sea-level rise).Here,we develop a simple yet comprehensive patch-dynamic framework for complex food web metacommunities subject to the competition-colonization tradeof between basal species.We found that oscillations in food web topological complexity(characterized by species diversity,mean food chain length and the degree of omnivory)emerge along the habitat destruction gradient.This outcome is robust to changing parameters or relaxing the assumption of a strict competitive hierarchy.Having oscillations in food web complexity indicates that small habitat changes could have disproportionate negative efects on species diversity,thus the success of conservation actions should be evaluated not only on changes in biodiversity,but also on system robustness to habitat alteration.Overall,this study provides a parsimonious mechanistic explanation for the emergence of food web complexity in island ecosystems,further enriching our understanding of metacommunity assembly.展开更多
The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions t...The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions to improve the process benefits and efficiency. Nevertheless, the performance assessment principally concentrates upon some parts of the entire system at present, for example the controller assessment. Although some researches focus on the whole process, they aim at discovering the relationships between profit, society, policies and so forth, instead of relations between overall performance and some manipulated variables, that is, the total plant performance. According to the big data of different performance statuses, this paper proposes a hierarchical framework to select some structured logic rules from monitored variables to estimate the current state of the process. The variables related to safety and profits are regarded as key factors to performance evaluation. To better monitor the process state and observe the performance variation trend of the process, a classificationvisualization method based on kernel principal component analysis(KPCA) and self-organizing map(SOM) is established. The dimensions of big data produced by the process are first reduced by KPCA and then the processed data will be mapped into a two-dimensional grid chart by SOM to evaluate the performance status. The monitoring method is applied to the Tennessee Eastman process. Monitoring results indicate that off-line and on-line performance status can be well detected in a two-dimensional diagram.展开更多
Rational construction of hierarchical multi-component materials with abundant heterostructure is evolving as a promising strategy to achieve excellent metal-organic frameworks(MOFs)based electromagnetic wave(EMW)absor...Rational construction of hierarchical multi-component materials with abundant heterostructure is evolving as a promising strategy to achieve excellent metal-organic frameworks(MOFs)based electromagnetic wave(EMW)absorbers.Herein,hierarchical heterostructure WS_(2)/CoS_(2)@carbonized cotton fiber(CCF)was fabricated using the ZIF-67 MOFs nanosheets anchored cotton fiber(ZIF-67@CF)as a precursor through the tungsten etching,sulfurization,and carbonization process.Apart from the synergetic effect of dielectric-magnetic dual-loss mechanism,the hierarchical heterostructure and multicomponent of WS_(2)/CoS_(2)@CCF also display improved impedance matching.Furthermore,numerous W-S-Co bands and heterojunction interfaces of heterogeneous WS_(2)/CoS_(2)are beneficial to promoting additional interfacial/dipole polarization loss and conductive loss,thereby enhancing the EMW attenuation performance.Based on the percolation theory,a good balance between impedance matching and EMW absorption capacity was achieved for the WS_(2)/CoS_(2)@CCF/paraffin composite with 20 wt.%filler loading,exhibiting strong EMW absorption capability with a minimum reflection loss(RLmin)value of−51.26 dB at 17.36 GHz with 2 mm thickness and a maximum effective absorption bandwidth(EABmax)as wide as 6.72 GHz.Our research will provide new guidance for designing high-efficient MOFs derived EMW absorbers.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(22001156)the Youth Talent Fund of University Association for Science and Technology in Shaanxi,China(20210602)+1 种基金King Abdullah University of Science and Technology(KAUST)Open access funding provided by Shanghai Jiao Tong University
文摘Improving the atom utilization of metals and clarifying the M–M’interaction is both greatly significant in assembling high-performance ultra-light electromagnetic wave-absorbing materials.Herein,a high-temperature explosion strategy has been successfully applied to assemble the hierarchical porous carbon sponge with Co–Fe decoration via the pyrolysis of the energetic metal organic framework.The as-constructed hybrid displays a superior reflection loss(RL)value of-57.7 d B and a specific RL value of-192 d B mg-1 mm-1 at 12.08 GHz with a layer thickness of 2.0 mm(loading of 15 wt%).The off-axis electron hologram characterizes the highly distributed numerous polarized nanodomain variable capacitors,demonstrating the dipole and interfacial polarization along the edges of the nanopores.More importantly,the X-ray absorption spectroscopy analysis verifies the mutual interaction between the metal cluster and carbon matrix and the electronic coupling responsible for the greatly improved electromagnetic wave absorption.
基金the financial support by the National Science Foundation of China(51822706 and 52107234)Beijing Natural Science Foundation(JQ19012)+2 种基金the DNL Cooperation Fund,CAS(DNL201912 and DNL201915)Innovation Academy for Green Manufacture Fund(IAGM2020C02)Youth Innovation Promotion Association,CAS(Y2021052).
文摘Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode cannot match the capacitor-type cathode, restricting the development of LICs. Herein, hierarchical carbon framework(HCF) anode material composed of 0D carbon nanocage bridged with 2D graphene network are developed via a template-confined synthesis process. The HCF with nanocage structure reduces the Li^(+) transport path and benefits the rapid Li^(+) migration, while 2D graphene network can promote the electron interconnecting of carbon nanocages. In addition, the doped N atoms in HCF facilitate to the adsorption of ions and enhance the pseudo contribution, thus accelerate the kinetics of the anode. The HCF anode delivers high specific capacity, remarkable rate capability. The LIC pouch-cell based on HCF anode and active HCF(a-HCF) cathode can provide a high energy density of 162 Wh kg^(-1) and a superior power density of 15.8 kW kg^(-1), as well as a long cycling life exceeding 15,000cycles. This study demonstrates that the well-defined design of hierarchical carbon framework by incorporating 0D carbon nanocages and 2D graphene network is an effective strategy to promote LIC anode kinetics and hence boost the LIC electrochemical performance.
基金B.X.thanks financial support from the National Natural Science Foundation of China(No.21801133)the Jiangsu Specially Appointed Professorship and Innovation and Entrepreneurship Talents in Jiangsu Province,the State Key Laboratory of Coordination Chemistry,the School of Chemistry and Chemical Engineering,and Collaborative Innovation Center of Advanced Microstructures,Nanjing University.
文摘Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments.Herein,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis method.The large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the material.Notably,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host material.The porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature pyrolysis.At the same time,they can also be used in various complex environments,such as acidic and basic environments.Ultimately,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 mm.After soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.
基金the Taishan Scholar Project of Shandong Province(No.tsqn201909115)And this work was partly supported by Qingdao University of Science and Technology Hua Xue 201919(No.QUSTHX201919).
文摘Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder their practical applications.Herein,a metal oxyacid salts-confined pyrolysis strategy is proposed to construct hierarchical porous metal oxide@carbon(MO@C,MO=MoO_(2),V_(2)O_(5),WO_(3))composites for solving the aforementioned problems.A water-evaporation-induced self-assembly mechanism has been put forward for fabricating the MO@polyvinyl pyrrolidone(PVP)@SiO_(2)precursors.After the following pyrolysis and etching process,small MO nanoparticles can be successfully encapsulated in the hierarchical porous carbon framework.Profiting from the synergistic effect of MO nanoparticles and highly conductive carbon framework,MO@C composites show excellent electrochemical properties.For example,the as-obtained MoO_(2)@C composite exhibits a large discharge capacity(1513.7 mAh·g^(−1)at 0.1 A·g^(−1)),good rate ability(443.5 mAh·g^(−1)at 5.0 A·g^(−1)),supernal long-lived stability(669.1 mAh·g^(−1)after 1000 cycles at 1.0 A·g^(−1)).This work will inspire the design of novel anode materials for high-performance LIBs.
基金supported by the National Key Research and Development Program Projects of China(No.2018YFC1504705)the National Natural Science Foundation of China(No.61731015)+1 种基金the Major instrument special project of National Natural Science Foundation of China(No.42027806)the Key Research and Development Program of Shaanxi(No.2022GY-331)。
文摘Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative particle swarm optimization(MHCHPSO)to optimize sensor deployment location and improve the coverage of WSN.MHCHPSO divides the population into three types topology:diversity topology for global exploration,fast convergence topology for local development,and collaboration topology for exploration and development.All topologies are optimized in parallel to overcome the precocious convergence of PSO.This paper compares with various heuristic algorithms at CEC 2013,CEC 2015,and CEC 2017.The experimental results show that MHCHPSO outperforms the comparison algorithms.In addition,MHCHPSO is applied to the WSN localization optimization,and the experimental results confirm the optimization ability of MHCHPSO in practical engineering problems.
基金supported by the National Key Technologies R&D Program of China(2021YFA0715302 and 2021YFE0191800)the National Natural Science Foundation of China(61975035 and 52203328)+2 种基金the Science and Technology Commission of Shanghai Municipality(22ZR1405000 and 20501130700)the China Postdoctoral Science Foundation(2022TQ0066 and 2022TQ0067)the Open Fund of the State Key Laboratory on Integrated Optoelectronics(IOSKL2020KF03).
文摘Precise assembly of active component with sophisticated confinement in electrocatalyst are promising to increase the active site exposure for enhanced hydrogen evolution reaction(HER).Here,PCN-333 films with mesopores are firstly assembled on titanium carbide MXene with the assistance of atomic layer deposited oxide nanomembrane.With the whereafter pyrolysis process,the composite is converted to Ndoped porous carbon multi-layer containing Fe nanoparticles.The strong confinement of Fe active particle in carbon as well as great contact between metal and carbon effectively enhance active site exposure.Furthermore,this multi-layer porous structure provides high specific surface area and plentiful mesopores for electrolyte penetration.Due to the structural advantage,the composite can be well functioned in both acid and alkaline electrolytes with excellent HER performance,e.g.,low overpotential/Tafel slope.The present work may have great potential in developing high efficiency transition-metal based electrocatalysts.
基金the National Key Research and Development Program(2019YFC1805804)the National Natural Science Foundation of China(22008032)+3 种基金the Guangdong Natural Science Foundation(2022A1515011192)the Guangdong Basic and Applied Basic Research Foundation(2019A1515110706)the Guangdong Provincial Key Lab of Green Chemical Product Technology(GC202111)the China Postdoctoral Science Foundation(2021M691059).
文摘The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs(NH-MOFs)with high crystallinity and excellent stability.This approach allows the morphology and porosity of MOFs to be fine tuned,thereby enabling the nanoscale crystal generation and a well-defined hierarchical system.The aqueous solution facilitates rapid nucleation kinetics,and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent(SDA)to guide the formation of hierarchical networks.The assynthesized NH-MOFs(NH-ZIF-67)were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of guest molecules,outperforming the parent microZIF-67.This study focuses on understanding the NH-MOF growth rules,which could allow tailor-designing NH-MOFs for various functions.
基金J.L.is supported by the Natural Science Foundation of China(No.32271548&31901175).
文摘Exploring how food web complexity emerges and evolves in island ecosystems remains a major challenge in ecology.Food webs assembled from multiple islands are commonly recognized as highly complex trophic networks that are dynamic in both space and time.In the context of global climate change,it remains unclear whether food web complexity will decrease in a monotonic fashion when undergoing habitat destruction(e.g.,the inundation of islands due to sea-level rise).Here,we develop a simple yet comprehensive patch-dynamic framework for complex food web metacommunities subject to the competition-colonization tradeof between basal species.We found that oscillations in food web topological complexity(characterized by species diversity,mean food chain length and the degree of omnivory)emerge along the habitat destruction gradient.This outcome is robust to changing parameters or relaxing the assumption of a strict competitive hierarchy.Having oscillations in food web complexity indicates that small habitat changes could have disproportionate negative efects on species diversity,thus the success of conservation actions should be evaluated not only on changes in biodiversity,but also on system robustness to habitat alteration.Overall,this study provides a parsimonious mechanistic explanation for the emergence of food web complexity in island ecosystems,further enriching our understanding of metacommunity assembly.
基金Supported by the National Natural Science Foundation of China(61590923,61422303,21376077)
文摘The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions to improve the process benefits and efficiency. Nevertheless, the performance assessment principally concentrates upon some parts of the entire system at present, for example the controller assessment. Although some researches focus on the whole process, they aim at discovering the relationships between profit, society, policies and so forth, instead of relations between overall performance and some manipulated variables, that is, the total plant performance. According to the big data of different performance statuses, this paper proposes a hierarchical framework to select some structured logic rules from monitored variables to estimate the current state of the process. The variables related to safety and profits are regarded as key factors to performance evaluation. To better monitor the process state and observe the performance variation trend of the process, a classificationvisualization method based on kernel principal component analysis(KPCA) and self-organizing map(SOM) is established. The dimensions of big data produced by the process are first reduced by KPCA and then the processed data will be mapped into a two-dimensional grid chart by SOM to evaluate the performance status. The monitoring method is applied to the Tennessee Eastman process. Monitoring results indicate that off-line and on-line performance status can be well detected in a two-dimensional diagram.
基金the National Natural Science Foundation of China(Nos.51803191 and 12072325)the National Key R&D Program of China(No.2019YFA0706802)+2 种基金the 111 project(No.D18023)Key Scientific and Technological Project of Henan Province(No.202102210038)the Deanship of Scientific Research at Umm Al-Qura University(No.22UQU4331100DSR01).
文摘Rational construction of hierarchical multi-component materials with abundant heterostructure is evolving as a promising strategy to achieve excellent metal-organic frameworks(MOFs)based electromagnetic wave(EMW)absorbers.Herein,hierarchical heterostructure WS_(2)/CoS_(2)@carbonized cotton fiber(CCF)was fabricated using the ZIF-67 MOFs nanosheets anchored cotton fiber(ZIF-67@CF)as a precursor through the tungsten etching,sulfurization,and carbonization process.Apart from the synergetic effect of dielectric-magnetic dual-loss mechanism,the hierarchical heterostructure and multicomponent of WS_(2)/CoS_(2)@CCF also display improved impedance matching.Furthermore,numerous W-S-Co bands and heterojunction interfaces of heterogeneous WS_(2)/CoS_(2)are beneficial to promoting additional interfacial/dipole polarization loss and conductive loss,thereby enhancing the EMW attenuation performance.Based on the percolation theory,a good balance between impedance matching and EMW absorption capacity was achieved for the WS_(2)/CoS_(2)@CCF/paraffin composite with 20 wt.%filler loading,exhibiting strong EMW absorption capability with a minimum reflection loss(RLmin)value of−51.26 dB at 17.36 GHz with 2 mm thickness and a maximum effective absorption bandwidth(EABmax)as wide as 6.72 GHz.Our research will provide new guidance for designing high-efficient MOFs derived EMW absorbers.
