Synthesis of highly-ordered mesoporous carbon/silica nanocomposites and derivative hierarchically mesoporous carbon from a phenyl-bridged organosiloxane

Nanoscale ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 245 ◽  
Author(s):  
Zhiwang Wu ◽  
Jiebin Pang ◽  
Yunfeng Lu
Keyword(s):  
Mesoporous Carbon ◽  
Ordered Mesoporous Carbon ◽  
Silica Nanocomposites ◽  
Ordered Mesoporous

Microwave Absorption Properties of Fe-Doped Ordered Mesoporous Carbon (CMK-3)/Silica Matrix Nanocomposites with Magnetic Multi-Resonance Mechanisms

NANO ◽  
2015 ◽  
Vol 10 (08) ◽  
pp. 1550110 ◽  
Author(s):  
Yanyan Ren ◽  
Le Yang ◽  
Liuding Wang ◽  
Hui Xing ◽  
Hongjing Wu
Keyword(s):  
Electron Microscope ◽  
Mesoporous Carbon ◽  
Magnetic Loss ◽  
Silica Matrix ◽  
Ordered Mesoporous Carbon ◽  
Metal Species ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Ordered Mesoporous ◽  
Cole Model

Low-density Fe-doped ordered mesoporous carbon (CMK-3)-silica (SBA-15) nanocomposites with different Fe contents have been prepared by a catalytic carbonization procedure followed by high-temperature calcination in N2. From field emission-scanning electron microscope (FE-SEM) and high resolution-transmission electron microscope (HR-TEM) images, it can be concluded that CMK-3 particles are dispersed homogeneously into a silica matrix and form a novel, special and interesting composite nanostructure. The metal species ([Formula: see text]18[Formula: see text]nm) are dispersed on the surface of frameworks during the catalytic carbonization procedure and endow a magnetic property to the carbon–silica nanocomposites. The optimal reflection loss (RL) calculated from the measured permittivity and permeability is [Formula: see text]19[Formula: see text]dB at 17.2[Formula: see text]GHz for an absorber thickness of 2.00[Formula: see text]mm. Moreover, the electromagnetic (EM) wave absorption less than [Formula: see text]10[Formula: see text]dB is found to exceed 5.76[Formula: see text]GHz as the layer thickness is 2.37 mm. The permittivity dispersion behaviors have been explained based on the Cole–Cole model and the conductivity contribution model. A new simple empirical model was also supposed to find the fitted curves of the multi-resonance imaginary permeability spectra of the composites. The EM wave can hardly be reflected on the absorber surface because of a better match between dielectric loss and magnetic loss, which originates from the combination of dielectric carbon–silica and magnetic Fe species.

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