Acid treatment of carbon nanofibres with encapsulated catalytic iron nanoparticles

Acid treatment was used to remove the Fe nanoparticles encapsulated in the carbon nanofibres grown by thermal chemical vapour deposition. Transmission electron microscopy was used to determine the structure of the carbon nanofibres. Field emission scanning electron microscopy and x-ray energy-dispersive spectroscopy were employed to analyse the effect of the treatment. It was found that treatment with HCl can partially remove the Fe nanoparticles on tips. Treatment using a mixture of HNO 3 and H 2 SO 4 is an effective way to remove the Fe nanoparticles on tips. Also, the tips of carbon nanofibres having Fe nanoparticles seem to be more stable against O 2 plasma etching than the bodies of the carbon nanofibres.