Supercritical CO2-assisted phase transformation from orthorhombic to hexagonal MoO3

摘要

The metastable hexagonal phase of molybdenum oxide (h-MoO3) have drawn much attention due to the novel one-dimensional tunnel structure and enhanced properties in physical, optical, chemical and electronic fields. Most of the researchers focused on the hydrothermal reaction to obtain h-MoO3 using NH4+, Na+ or K+ ion as the structure-directing agents and stabilizer of the h-MoO3, which will definitely hinder the further application of h-MoO3. In this work, for the first time, we demonstrate a novel top-down method to obtain metastable h-MoO3 via a topotactic phase transformation with the assistance of super-critical carbon dioxide (SC CO2). Our study indicates that this successful phase transformation is due to distortion of MoO6 octahedra units that might be induced by the surface tension change. (C) 2017 Elsevier B.V. All rights reserved.