Synthesis of hybrid nanographite particles using fluidized bed system

Abstract

Nanographite coated with ferromagnetic substances such as iron or iron oxide is a potential material for microwave absorption because of its favorable structural, magnetic, and electrical characteristics. In this paper, deposition on surfaces of acid functionalized and microwave-exfoliated nanographite particles with the use of fluidized bed system is reported. Acid functionalization improves iron adhesion and exfoliation reduces the flake thickness. The parameters influencing the deposition process are considered. It is demonstrated that Faraday’s laws of electrolysis can be used for these systems if the charge transfer from solid cathode to bed particles is uniform. This requirement is satisfied only above some critical values of suspension density, electrolyte concentration, and stirring rate. The optimized values of current density are required for each specific system, as low current density leads to non-uniform deposition with local nucleation, when high a current density induces too rapid nucleation and promotes iron hydroxo complex formation. Deposition time also should be optimized for any specific system, as the expected amount of deposit cannot be formed longer because of side reactions.