Synthesis of few-walled carbon nanotube-Rh nanoparticles by arc discharge: Effect of selective oxidation

► High-crystallinity CNTs and FeRh nanoparticles were simultaneously generated in arc plasma. ► The diameter distribution of CNTs depends on different gases. ► Heat treatment in open air and soaking in HCl can convert CNTs-FeRh to CNTs-Rh. ► The selective oxidation mechanisms of metal nanoparticles and carbon materials differ.