Controllable and Large-Scale Synthesis of Carbon Nanofibers, Bamboo-Like Nanotubes, and Chains of Nanospheres over Fe/SnO₂ and Their Microwave-Absorption Properties

Abstract

Carbon nanofibers (CNFs), bamboo-like carbon nanotubes (CNTs), and chains of carbon nanospheres (CNSs) were produced selectively in large quantities in the pyrolysis of acetylene at 500, 600, and 700 °C, respectively, over Fe/SnO2 nanoparticles generated by means of a combined sol−gel and hydrogen-reduction method. One advantage of this approach is that there is no need of using a dilute gas such as argon or nitrogen. It is found that the pyrolysis temperature has considerable effect on the yield, morphology, and microwave-absorption properties of the obtained materials. The corresponding yields of CNFs, bamboo-like CNTs, and chains of CNSs are high, up to 25595, 36791, and 37039%, respectively. Thus, a simple and environment-friendly approach has been proposed for mass production of CNFs, bamboo-like CNTs, and chain of CNSs in a controllable manner. In addition, the as-prepared carbon materials are demonstrated to show good microwave-absorption properties. On the basis of the results, we propose a possible formation mechanism.

Fabrication of hierarchical graphene@Fe3O4@SiO2@polyaniline quaternary composite and its improved electrochemical performance

“…Firstly, the multi-interfaces and triple junctions (graphene@Fe 3 O 4 , Fe 3 O 4 @SiO 2 , SiO 2 @PANI) are advantageous for electromagnetic attenuation due to the existing interfacial polarization [22]. Secondly, the PANI and the void space existing between Fe 3 O 4 and PANI result in relatively large specific surfaces areas, providing more active sites for reflection and scattering of electromagnetic wave [23]. Finally, the void space between Fe 3 O 4 and PANI can effectively interrupt the spread of electromagnetic wave and generate dissipation due to the existing impendence difference and enhanced the microwave absorption properties [24].…”

Controllable and Large-Scale Synthesis of Carbon Nanostructures: A Review on Bamboo-Like Nanotubes

“…Moreover, it was found that, when using acetylene decomposition over Fe nanoparticles to synthesize CNTs, the addition of different amounts of H2 led to the formation of CNTs with various helicities [46]. Afterwards, the same authors synthesized Fe/SnO2 nanoparticles by using a combined sol-gel/reduction method and then used this catalyst in the pyrolysis of acetylene for selective synthesis of carbon nanofibers (CNFs), bamboo-like carbon nanotubes (CNTs), and chains of carbon nanospheres (CNSs) [47]. They found that the pyrolysis temperature, 500, 600, or 700 °C, had a considerable effect on the yield, morphology, and microwave absorption properties of the obtained materials.…”

“…or CO feedstocks and various metal particle catalysts such as Fe, Ni, or Co have been used for the growth of MWCNT on different substrates by CVD. Typical bamboo-like CNFs obtained from the Ni 47 Cu 53 /CNT catalyst at 750 • C are shown in Figure 6.…”

Controllable synthesis of leaflet-like poly (3,4-ethylenedioxythiophene)/single-walled carbon nanotube composites with microwave absorbing property

“…Qi et al reported the microwave absorbing property of bamboo-like carbon nanotubes over Fe/SnO 2 composite and the minimum reflection loss was À11.06 dB at 12.45 GHz [13]. A composite of epoxy-silicone filled with multi-walled carbon nanotubes (MWCNTs) and carbonyl iron particles was used as microwave absorber and showed a minimum reflection loss of À16.9 dB at 10.5 GHz.…”