Comparison of functionalized carbon nanofibers and multi-walled carbon nanotubes as supports for Fe–Co nanoparticles

Abstract

Multi-walled carbon nanotubes (MWCNT) and nanofibers (CNF) have been functionalized at their surfaces with chelating phosphine (PPh₂) and ammonium (NMe₃⁺) groups, as anchoring sites for metal complexes. The surface functionalization has been monitored by XPS, elemental analyses, N₂ physisorption and/or SEM surface morphology analysis at each step. Bimetallic Fe–Co nanoparticles from two different starting cluster complexes, [HFeCo₃(CO)₁₂] (1) and (NEt₄)[FeCo₃(CO)₁₂] (2), have been deposited onto the surfaces of the functionalized MWCNT and CNF as well as their pristine forms for comparison. The samples have been fully characterized before and after thermal treatment. The obtained nanoparticles were shown by TEM to be better dispersed and of smaller size on functionalized than on pristine supports. Magnetic characterization revealed blocked superparamagnetic Fe–Co nanoparticles together with paramagnetic ions on CNF as well as MWCNT.