The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the rel...The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.展开更多
Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy c...Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy catalysts.Comparative and systematic studies have been carried out on the morphology,structural characteristics and graphitic crystallinity of these CNOs products.Furthermore,the electrochemical hydrogen storage properties of three types of CNOs have been investigated.Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g,coiTesponding to a hydrogen storage of 1.42%.This comparison study shows the advantages of each catalyst in the growth of CNOs.enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.展开更多
Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400℃ by using Fe/Al2O3 as catalyst. The product was refluxed in 36% concentrated HCl at 60℃ for 48 h in order to re-move the cata...Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400℃ by using Fe/Al2O3 as catalyst. The product was refluxed in 36% concentrated HCl at 60℃ for 48 h in order to re-move the catalyst support. The samples were examined by scanning and high resolution transmission electron microscopy,energy dispersive spectroscopy and X-ray diffraction. The results show that nano onion-like fullerenes encapsulating a Fe3C core were obtained. These had a structure of stacked graphitic fragments,with diameters ranging from 15―50 nm. When the product was further heat-treated at 1100℃ for 2 h,nano onion-like fullerenes with a clear concentric graphitic layer structure were obtained. The growth mechanism of nano onion-like fullerenes encapsulating metal cores is suggested to follow a vapor-solid growth model.展开更多
Onion-like Fullerenes were produced at high-temperature in vacuum. The morphology of the carbon nano onion-like fullerenes was examined and characterized by high-resolution transmission electron microscopy (HRTEM). It...Onion-like Fullerenes were produced at high-temperature in vacuum. The morphology of the carbon nano onion-like fullerenes was examined and characterized by high-resolution transmission electron microscopy (HRTEM). It can be seen that the nano-sized, onion-like fullerenes possess high degree of graphization. The results suggested that the catalyst is the main factor affecting the size and yield of the fullerenes. The method is very promising for simple mass production.展开更多
基金This work was supported by the National Key Research and Development Program of China(Grant No.2019YFE0122900)the National Natural Science Foundation of China(No 51971162,U1933112,51671146)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M671208)Open access funding provided by Shanghai Jiao Tong University
文摘The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.
基金supported by the National Natural Science Foundation of China(51272173,51002188)the National Basic Research Program of China(2010CB934703)Tianjin Municipal Science and Technology Commission(12ZCZDGX00800)
文摘Three types of carbon nano-onions（CNOs） including Ni@CNOs.Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850 ℃ using nickel,iron and iron-nickel alloy catalysts.Comparative and systematic studies have been carried out on the morphology,structural characteristics and graphitic crystallinity of these CNOs products.Furthermore,the electrochemical hydrogen storage properties of three types of CNOs have been investigated.Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g,coiTesponding to a hydrogen storage of 1.42%.This comparison study shows the advantages of each catalyst in the growth of CNOs.enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.
基金Supported by National Natural Science Foundation of China (Grant Nos.20471041,20676086 and 20673072)
文摘Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400℃ by using Fe/Al2O3 as catalyst. The product was refluxed in 36% concentrated HCl at 60℃ for 48 h in order to re-move the catalyst support. The samples were examined by scanning and high resolution transmission electron microscopy,energy dispersive spectroscopy and X-ray diffraction. The results show that nano onion-like fullerenes encapsulating a Fe3C core were obtained. These had a structure of stacked graphitic fragments,with diameters ranging from 15―50 nm. When the product was further heat-treated at 1100℃ for 2 h,nano onion-like fullerenes with a clear concentric graphitic layer structure were obtained. The growth mechanism of nano onion-like fullerenes encapsulating metal cores is suggested to follow a vapor-solid growth model.
基金supported by National Natural Science Foundation(59871032,90306014)National Excellent Youth Foundation(50025103).
文摘Onion-like Fullerenes were produced at high-temperature in vacuum. The morphology of the carbon nano onion-like fullerenes was examined and characterized by high-resolution transmission electron microscopy (HRTEM). It can be seen that the nano-sized, onion-like fullerenes possess high degree of graphization. The results suggested that the catalyst is the main factor affecting the size and yield of the fullerenes. The method is very promising for simple mass production.
基金National Basic Research Program of China (2004CB217808)National Nature Science Foundation of China (20676086)+1 种基金Program for New Century Excellent Talent in University ( NCET-06-0262)International S&T Cooperation Program(2007DFA50940)~~
