IN-SITU CATALYST-FREE SYNTHESIS OF SHORT MULTI-WALLED CARBON NANOTUBES ON POLYMER DERIVED CERAMIC BY MOLECULAR SELF-ASSEMBLY METHOD

摘要

Carbon nanotubes (CNTs) have attracted great interests from both academy and industry due to their unique structures, superior properties, and widespread potential applications in nano-scaled electronic device, drug delivery, chemical and biological sensors, catalyst support, energy storage and composites [1-3]. Since its discovery in 1992, a variety of techniques has been developed for synthesizing CNTs, including electric arc-discharge [4-6], laser ablation [7], chemical vapor deposition (CVD) [8,9], hydrothermal processing [10], and microwave synthesis [11]. One disadvantage of these techniques is that they generally require metallic catalysts for the growth of carbon nanotubes. Such metallic catalysts caused many problems in fundamental studies and applications of CNTs. While many efforts have been devoted to remove the catalysts, it is demonstrated that it is very difficult to complete removal of them without introducing defects and contaminations. Therefore, it is highly desired to synthesis CNTs in a catalyst-free manner. Recently, several efforts have been made to synthesize single walled carbon nanotubes via a metal-catalyst-free CVD process [12]. However, this method suffers from shortcomings such as low yield and complex process. Catalyst-free synthesis of CNTs with desired diameters and lengths still remains a huge technical challenge. Here we report, for the first time, the catalyst-free synthesis of short multi-walled carbon nanotubes on the polymer derived ceramics. This method is based on a self assemble system of surfactant polymer in solution following annealing at high temperature under inert gas atmosphere in a furnace. Different from other conventional preparation method of CVD, the obtained MWNTs prepared by this polymer self assemble strategy has some advantages. Such as, no metal catalysts used and short CNTs obtained.