The swift advancement of electronics technology has led to a burgeoning interest in multifunctionaliz-ing electromagnetic wave(EMW)absorption materials as a prospective avenue for future development.However,the effect...The swift advancement of electronics technology has led to a burgeoning interest in multifunctionaliz-ing electromagnetic wave(EMW)absorption materials as a prospective avenue for future development.However,the effective integration of diverse functions within a single material continues to present chal-lenges.This work successfully fabricated a three-dimensional(3D)porous Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC frame-work with carbon microspheres through uncomplicated freeze-drying and high-temperature pyrolysis techniques.The resultant magnetic bimetallic carbide(Co_(6)Mo_(6)C_(2) and Mo_(2)C)nanoparticles are uniformly and densely embedded within the carbon layer,facilitated jointly by a rigid template(molybdenum salt)and a flexible template(glucose),thus realizing an exceptional dual loss mechanism involving dielectric and magnetic components.The establishment of the 3D porous conductive network enhances EMW ab-sorption through multiple reflections and scattering mechanisms.Impressively,the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework attains remarkable EMW absorption characteristics with ultralightweight(0.1567 g cm^(-3)),ul-trathin matching thickness(1.7 mm),and robust absorption(reflection loss R_(L) value of-65.89 dB).Fur-thermore,it achieves a noteworthy effective absorption bandwidth(EAB,R_(L)≤-10 dB)spanning 6.4 GHz,ensuring complete absorption of 100%within the X band(8-12 GHz)at a matching thickness of 2 mm.In addition,the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework exhibits pronounced hydrophobicity and magnetic respon-siveness,bestowing upon it appealing attributes including self-cleaning,flame retardancy,and thermal insulation,on par with those observed in commercial products.The radar cross-sectional area(RSC)re-duction value of the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework can reach 35.2 dB m^(2) by RSC simulation,which can effectively lower the likelihood of detection by radar detectors for the target.This study presents a viable strategy for the advancement of novel lightweight and multifunctional materials that demonstrate exceptional performance in absorbing electromagnetic waves.展开更多
Here we demonstrate the synthesis of multifunctionalised benzimidazoles through the coupling of o-phenylenediamine with aldehydes by using Copper (II) hydroxide as an efficient solid catalyst in methanol at room tempe...Here we demonstrate the synthesis of multifunctionalised benzimidazoles through the coupling of o-phenylenediamine with aldehydes by using Copper (II) hydroxide as an efficient solid catalyst in methanol at room temperature. The Copper (II) hydroxide solid catalyst gave better yields (80%-99%) in short reaction time (4-8 h). These commercially available cheap catalysts are more active than many reported expensive heterogeneous catalysts. Using the Copper hydroxide fresh catalyst, the yield of product 3a was 98%, while the recovered catalyst in the three subsequent cycles gave the yield of 94%, 90% and 88% respectively.展开更多
基金This work was supported by the National Natural Science Foun-dation of China(No.22269010)the Jiangxi Provincial Natural Sci-ence Foundation(No.20224BAB214021)+3 种基金the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(No.20212BCJ23020)the Science and Technology Project of Jiangxi Provincial Department of Education(No.GJJ211305)the Opening Project of National Engineering Research Center for Do-mestic&Building Ceramics(No.GXZX2302)the Graduate In-novation Fund of Jiangxi Province(YC2023-S799).
文摘The swift advancement of electronics technology has led to a burgeoning interest in multifunctionaliz-ing electromagnetic wave(EMW)absorption materials as a prospective avenue for future development.However,the effective integration of diverse functions within a single material continues to present chal-lenges.This work successfully fabricated a three-dimensional(3D)porous Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC frame-work with carbon microspheres through uncomplicated freeze-drying and high-temperature pyrolysis techniques.The resultant magnetic bimetallic carbide(Co_(6)Mo_(6)C_(2) and Mo_(2)C)nanoparticles are uniformly and densely embedded within the carbon layer,facilitated jointly by a rigid template(molybdenum salt)and a flexible template(glucose),thus realizing an exceptional dual loss mechanism involving dielectric and magnetic components.The establishment of the 3D porous conductive network enhances EMW ab-sorption through multiple reflections and scattering mechanisms.Impressively,the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework attains remarkable EMW absorption characteristics with ultralightweight(0.1567 g cm^(-3)),ul-trathin matching thickness(1.7 mm),and robust absorption(reflection loss R_(L) value of-65.89 dB).Fur-thermore,it achieves a noteworthy effective absorption bandwidth(EAB,R_(L)≤-10 dB)spanning 6.4 GHz,ensuring complete absorption of 100%within the X band(8-12 GHz)at a matching thickness of 2 mm.In addition,the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework exhibits pronounced hydrophobicity and magnetic respon-siveness,bestowing upon it appealing attributes including self-cleaning,flame retardancy,and thermal insulation,on par with those observed in commercial products.The radar cross-sectional area(RSC)re-duction value of the Co_(6)Mo_(6)C_(2)/Mo_(2)C@NC framework can reach 35.2 dB m^(2) by RSC simulation,which can effectively lower the likelihood of detection by radar detectors for the target.This study presents a viable strategy for the advancement of novel lightweight and multifunctional materials that demonstrate exceptional performance in absorbing electromagnetic waves.
文摘Here we demonstrate the synthesis of multifunctionalised benzimidazoles through the coupling of o-phenylenediamine with aldehydes by using Copper (II) hydroxide as an efficient solid catalyst in methanol at room temperature. The Copper (II) hydroxide solid catalyst gave better yields (80%-99%) in short reaction time (4-8 h). These commercially available cheap catalysts are more active than many reported expensive heterogeneous catalysts. Using the Copper hydroxide fresh catalyst, the yield of product 3a was 98%, while the recovered catalyst in the three subsequent cycles gave the yield of 94%, 90% and 88% respectively.
