Iron cation-induced biphase symbiosis of h-WO3/o-WO3·0.33H2O and their crystal phase transition

Abstract

Herein, tungsten oxide hexagonal prisms with a biphase of h-WO₃ and o-WO₃·0.33H₂O were prepared by a facile hydrothermal method using Fe³⁺ cations. The combination of instrumental characterization and software simulation proved that two phases coexisted in one nanoparticle with same morphology. The ratio of two phases could be changed by adjusting the concentration of Fe³⁺ cations. On the basis of controlled experiments, a mechanism was proposed to illustrate the formation of this biphase WO₃ structure, and it was also proved that the self-growth of Fe species was unfavorable for the coexistence of two phases.