Synthesis of Oxide Nanopowders in NanoSpray^SM Diffusion Flames

Abstract

Combustion chemical vapor condensation (ccvc) is described for production of metal oxide nanoparticles by decomposing metalorganic precursors in NanoSpray^SM diffusion flames. CCVC involves atomization and controlled thermal decomposition of liquid precursors that can yield crystalline nanopowders with sizes ranging from 2 to 50 nm. The atomization of liquid precursors into an ultrafine mist of submicron-size droplets enables rapid evaporation and formation of vaporous material in the flame. The synthesized nanopowders are then collected by continuous baghouse filtering. This article describes the flame synthesis of pure and doped ZnO and CeO₂ nanopowders. Nanopowder particle size, crystallinity, morphology, and composition were characterized by x-ray diffraction analysis, surface area analysis, and transmission electron microscopy. Flame-made nanopowders are of high purity, and appear to be made of individual nanoparticles and loose aggregates, with surface area ranging from 50 to more than 200 m²/g.

Keywords:

• Nanoparticles
• Synthesis
• Flame
• NanoSpray^SM process
• CCVD
• CCVC
• Zinc oxide
• Cerium oxide
• TEM

Acknowledgments

The authors want to thank Prof. Rosaria Gerhardt for BET surface analysis, Prof. Z.L. Wang for transmission electron microscopy, and Dr. Scott Flanagan for help in preparing the manuscript.