Crystal phase- and morphology-controlled synthesis of MoO3 materials

Abstract

The crystal phase and morphology of MoO₃ materials were precisely tuned under suitable synthetic conditions and mutual transformation of h-MoO₃ and α-MoO₃ was achieved via a facile hydrothermal method for the first time. The h-MoO₃ microrods with a diameter of 0.5–1.6 μm and length of 2.2–6.1 μm were fabricated with the assistance of NaNO₃ using α-MoO₃ particles as the precursor. The transformation of h-MoO₃ microrods to α-MoO₃ nanobelts with a diameter of 150–430 nm and length of 2.1–14.5 μm occurred through hydrothermal techniques at higher temperature. Systematic studies of synthetic parameters revealed that the hexagonal h-MoO₃ microrods formed at higher concentration of NaNO₃, while h-MoO₃ microrods vanished at higher temperature with prolonged time and α-MoO₃ nanobelts were exclusively produced. The h-MoO₃ microrods exhibited higher catalytic activity in photo-degradation of methylene blue than the α-MoO₃ nanobelts. This is ascribed to the weaker fluorescence and reduced bandgap energy of the h-MoO₃ microrods than those of the α-MoO₃ nanobelts.