Synthesis of α-MoO3 nanobelts with preferred orientation and good photochromic performance

Abstract

Stable phase α-MoO₃ nanobelts with preferred orientation were successfully evolved on transforming from metastable phase h-MoO₃via an aqueous approach. H⁺ ions play a key role in the nuclei formation and crystal growth processes. Variation of the Mo : H⁺ molar ratio led to MoO₃ crystals with different polymorphs. Oriented α-MoO₃ nanobelts along the [001] direction were achieved under a Mo : H⁺ ratio of 1 : 9, which is relative to a heterogeneous nucleation process on the surface of metastable phase h-MoO₃. The α-MoO₃ nanobelts along the [100] direction were obtained under a Mo : H⁺ ratio of 1 : 10; homogeneous nucleation dominated the synthesis without the presentation of h-MoO₃ microrods. The α-MoO₃ nanobelts with distinguishing crystalline growth orientations exhibited different photochromic behaviors.