Synthesis of spherical bismuth nanoparticles by two-step heating of tetraethylene glycol containing solid bismuth(III) carbonates

Synthesis of nano-sized spherical bismuth particles was implemented by a novel polyol method using insoluble solid Bi(III) subcarbonate particles. The Bi(III) subcarbonate precursor was directly reduced and gradually transformed to Bi nanoparticles (NPs) from 240 °C with an increase of temperature during a two-step heating process to 300 °C. Although some Bi(III) subcarbonate platelets were not transformed completely to the Bi NPs even after heating to 300 °C, complete removal of the Bi(III) subcarbonate platelets and the enhanced sphericity of the synthesized Bi NPs were accomplished with a holding step at the target temperature for 35 min. The Bi NPs were synthesized under optimized conditions, including preheating at 200 °C for 1 h. The Bi NPs had an average diameter of approximately 60 nm, and they exhibited excellent sphericity and dispersity.