Controlled Synthesis of Nanocrystalline Anatase and Rutile through Thermal Plasma Processing

Abstract

Mono-dispersed, uniform, and highly crystallized TiO₂ nanocrystallites (10-50 nm) with controlled phase structures (anatase and rutile) were synthesized by a novel process based on rapid oxidation of in-flight TiC micrometer-size powder in an aerosol reactor at the thermal plasma high temperatures (3,000-10,000 K). The TiO₂ nanocrystallites formed in the Ar-O₂ plasma consisted of isolated single crystal particles of anatase with spherical shapes and rutile grains crystallized in a hexagonal morphology. The fraction of anatase increased greatly with increasing oxygen flow rate in the Ar-O₂ plasma.