Sonochemical Synthesis of Carbon Nanotubes and Nanoonions Under Ambient Conditions Using a SINW Template

Under ambient conditions, room-temperature and atmospheric-pressure, carbon nanotubes (CNTs) and carbon nanoonions (CNOs) were synthesized by reacting silicon nanowires (SiNWs) with organic solvents in a laboratory sonicator. As many common organic solvents are applicable and SiNWs can be produced plentifully from the oxide-assisted growth process, this simple method using the mildest growth conditions provides a convenient, inexpensive synthesis of large quantities of CNTs and CNOs. We believe both the local high temperature caused by sonication and the reductive power of the hydrogen-passivated SiNW (oxide-coated SiNW did not work) contribute to the conversion of the organic solvent molecules to graphite sheets which wrap around the SiNWs or Si nanoparticles (SiNP) to form CNTs or CNOs, respectively. With proper tuning (e.g. solvent type and temperature, ultrasonic power, etc), the sonochemical process can be adapted for mass production of either CNTs or CNOs.