Effect of carbon nanotexture on the synthesis, initial growth mechanism and photoluminescence properties of SiC nanowires

Although the spontaneous vapor-solid growth of SiC nanowires is a well-established phenomenon, the exact mechanism by which nanowires grow on substrates is still poorly understood. Here, we studied the initial growth of SiC nanowires on carbon sources with different nanotextures via a catalyst-free vapor reaction between a polyacrylonitrile-based carbon fiber and a silicon powder. The results revealed that the SiC nanowires were preferentially formed on the carbon fiber with a higher degree of graphitization. Detailed analyses suggested that the growth behavior of the underlying SiC film formed on the carbon fibers, which is strongly affected by the microstructures of the carbon fibers, plays an important role in the formation of nanowires. In addition, the photoluminescence spectrum of SiC nanowires showed strong ultraviolet-visible emission peaks at an excitation wavelength of 250 nm, which may provide potential applications in the field of optoelectronic devices.

Importing Tin Nanoparticles into Biomass-Derived Silicon Oxycarbides with High-Rate Cycling Capability Based on Supercritical Fluid Technology

Silicon oxycarbides (SiOC) are regarded as potential anode materials for lithium-ion batteries, although inferior cycling stability and rate performance greatly limit their practical applications. Herein, amorphous SiOC is synthesized from Chlorella by means of a biotemplate method based on supercritical fluid technology. On this basis, tin particles with sizes of several nanometers are introduced into the SiOC matrix through the biosorption feature of Chlorella. As lithium-ion battery anodes, SiOC and Sn@SiOC can deliver reversible capacities of 440 and 502 mAh g^-1 after 300 cycles at 100 mA g^-1 with great cycling stability. Furthermore, as-synthesized Sn@SiOC presents an excellent high-rate cycling capability, which exhibits a reversible capacity of 209 mAh g^-1 after 800 cycles at 5000 mA g^-1 ; this is 1.6 times higher than that of SiOC. Such a novel approach has significance for the preparation of high-performance SiOC-based anodes.

Selective growth of zinc blende, wurtzite and hybrid SiC nanowires via a simple chemical vapor deposition route

3C-SiC, 2H-SiC and their hybrid nanowires were synthesized in a controllable manner via changing CH₄ flow rates. It is found that higher CH₄ supply facilitates the wurtzite phase growth, while the other phases formed when decreasing the flow rate.