Synthesis of single-walled carbon nanotube/metal nanoparticle hybrid materials from potassium-filled nanotubes

The reducing property of potassium-filled single-walled carbon nanotubes (SWCNTs) was used to synthesize single-walled carbon nanotube/metal nanoparticle hybrid materials. Electron transfer from potassium to SWCNTs gives rise to a substantial enhancement of the reducing ability of the carbon nanotubes. Metal ions with redox potentials lower than that of pristine SWCNTs can be reduced by potassium-filled SWCNTs. SWCNTs decorated with copper and zinc nanoparticles were synthesized through redox reactions between potassium-filled SWCNTs and metal ions. These redox reactions cannot take place if the potassium-filled SWCNTs have been exposed to air, because of oxidation of the carbon nanotubes which is shown by a shift of the G band frequency in Raman spectra.