Using SiC nanowires(SiCNWs)as the substrate,reflux-annealing and electrodeposition-carbonization were sequentially applied to integrate SiC nanowires with magnetic Fe_(3)O_(4) nanoparticles and amorphous nitrogen-dope...Using SiC nanowires(SiCNWs)as the substrate,reflux-annealing and electrodeposition-carbonization were sequentially applied to integrate SiC nanowires with magnetic Fe_(3)O_(4) nanoparticles and amorphous nitrogen-doped carbon(NC)for the fabrication of SiCNWs@Fe_(3)O_(4)@NC nanocomposite.Comprehensive testing and characterization of this product provided valuable insights into the im-pact of structural and composition changes on its electromagnetic wave absorption performances.The optimized SiCNWs@Fe_(3)O_(4)@NC nanocomposite,which has 30wt%filler content and a corresponding thickness of 2.03 mm,demonstrates exceptional performance with the minimum reflection loss(RL_(min))of-53.69 dB at 11.04 GHz and effective absorption bandwidth(EAB)of 4.4 GHz.The synergistic effects of the enhanced nanocomposite on electromagnetic wave absorption were thoroughly elucidated using the theories of multiple scattering,polarization relaxation,hysteresis loss,and eddy current loss.Furthermore,a multicomponent electromagnetic wave attenu-ation model was established,providing valuable insight into the design of novel absorbing materials and the enhancement of their absorp-tion performances.This research demonstrated the significant potential of the SiCNWs@Fe_(3)O_(4)@NC nanocomposite as a highly efficient electromagnetic wave-absorbing material with potential applications in various fields,such as stealth technology and microwave absorption.展开更多
Defect engineering in transition metal oxides semiconductors(TMOs)is attracting considerable interest due to its potential to enhance conductivity by intentionally introducing defects that modulate the electronic stru...Defect engineering in transition metal oxides semiconductors(TMOs)is attracting considerable interest due to its potential to enhance conductivity by intentionally introducing defects that modulate the electronic structures of the materials.However,achieving a comprehensive understanding of the relationship between micro-structures and electromagnetic wave absorption capabilities remains elusive,posing a substantial challenge to the advancement of TMOs absorbers.The current research describes a process for the deposition of a MoO_(3)layer onto SiC nanowires,achieved via electro-deposition followed by high-temperature calcination.Subsequently,intentional creation of oxygen vacancies within the MoO_(3)layer was carried out,facilitating the precise adjustment of electromagnetic properties to enhance the microwave absorption performance of the material.Remarkably,the SiC@MO-t4 sample exhibited an excellent minimum reflection loss of-50.49 dB at a matching thickness of 1.27 mm.Furthermore,the SiC@MO-t6 sample exhibited an effective absorption bandwidth of 8.72 GHz with a thickness of 2.81 mm,comprehensively covering the entire Ku band.These results not only highlight the pivotal role of defect engineering in the nuanced adjustment of electromagnetic properties but also provide valuable insight for the application of defect engineering methods in broadening the spectrum of electromagnetic wave absor ption effectiveness.SiC@MO-t samples with varying concentrations of oxygen vacancies were prepared through in-situ etching of the SiC@MoO_(3)nanocomposite.The presence of oxygen vacancies plays a crucial role in adjusting the band gap and local electron distribution,which in turn enhances conductivity loss and induced polarization loss capacity.This finding reveals a novel strategy for improving the absorption properties of electromagnetic waves through defect engineering.展开更多
基金supported by the National Natural Science Foundation of China(Nos. 52072196, 52002200, 52102106,52202262, 22379081, and 22379080)Major Basic Research Program of Natural Science Foundation of Shandong Province,China(No. ZR2020ZD09)+2 种基金Natural Science Foundation of Shandong Province,China(Nos. ZR2020QE063, ZR2022ME090, and ZR2023QE059)supported by the Visiting Scholar Fellowship Funding for Teachers in Shandong Province’s General Undergraduate Institutionsthe Visiting Research Fund for Teachers of Ordinary Undergraduate Universities of Shand ong Province
文摘Using SiC nanowires(SiCNWs)as the substrate,reflux-annealing and electrodeposition-carbonization were sequentially applied to integrate SiC nanowires with magnetic Fe_(3)O_(4) nanoparticles and amorphous nitrogen-doped carbon(NC)for the fabrication of SiCNWs@Fe_(3)O_(4)@NC nanocomposite.Comprehensive testing and characterization of this product provided valuable insights into the im-pact of structural and composition changes on its electromagnetic wave absorption performances.The optimized SiCNWs@Fe_(3)O_(4)@NC nanocomposite,which has 30wt%filler content and a corresponding thickness of 2.03 mm,demonstrates exceptional performance with the minimum reflection loss(RL_(min))of-53.69 dB at 11.04 GHz and effective absorption bandwidth(EAB)of 4.4 GHz.The synergistic effects of the enhanced nanocomposite on electromagnetic wave absorption were thoroughly elucidated using the theories of multiple scattering,polarization relaxation,hysteresis loss,and eddy current loss.Furthermore,a multicomponent electromagnetic wave attenu-ation model was established,providing valuable insight into the design of novel absorbing materials and the enhancement of their absorp-tion performances.This research demonstrated the significant potential of the SiCNWs@Fe_(3)O_(4)@NC nanocomposite as a highly efficient electromagnetic wave-absorbing material with potential applications in various fields,such as stealth technology and microwave absorption.
基金supported by the National Natural Science Foundation of China under Grant Nos. 52072196, 52002200, 52102106, 52202262, 22379081, 22379080Major Basic Research Program of Natural Science Foundation of Shandong Province under Grant No. ZR2020ZD09+1 种基金the Natural Science Foundation of Shandong Province under Grant Nos. ZR2020QE063, ZR2022ME090, ZR2023QE059. Moreoversupported by the Visiting Scholar Fellowship Funding for Teachers in Shandong Province’s General Undergraduate Institutions
文摘Defect engineering in transition metal oxides semiconductors(TMOs)is attracting considerable interest due to its potential to enhance conductivity by intentionally introducing defects that modulate the electronic structures of the materials.However,achieving a comprehensive understanding of the relationship between micro-structures and electromagnetic wave absorption capabilities remains elusive,posing a substantial challenge to the advancement of TMOs absorbers.The current research describes a process for the deposition of a MoO_(3)layer onto SiC nanowires,achieved via electro-deposition followed by high-temperature calcination.Subsequently,intentional creation of oxygen vacancies within the MoO_(3)layer was carried out,facilitating the precise adjustment of electromagnetic properties to enhance the microwave absorption performance of the material.Remarkably,the SiC@MO-t4 sample exhibited an excellent minimum reflection loss of-50.49 dB at a matching thickness of 1.27 mm.Furthermore,the SiC@MO-t6 sample exhibited an effective absorption bandwidth of 8.72 GHz with a thickness of 2.81 mm,comprehensively covering the entire Ku band.These results not only highlight the pivotal role of defect engineering in the nuanced adjustment of electromagnetic properties but also provide valuable insight for the application of defect engineering methods in broadening the spectrum of electromagnetic wave absor ption effectiveness.SiC@MO-t samples with varying concentrations of oxygen vacancies were prepared through in-situ etching of the SiC@MoO_(3)nanocomposite.The presence of oxygen vacancies plays a crucial role in adjusting the band gap and local electron distribution,which in turn enhances conductivity loss and induced polarization loss capacity.This finding reveals a novel strategy for improving the absorption properties of electromagnetic waves through defect engineering.
