Novel Metastable Hexagonal MoO3 Nanobelts: Synthesis, Photochromic, and Electrochromic Properties

Abstract

In this work, we report the crystalline structure, morphology, and optical properties of novel metastable hexagonal phase MoO 3 ( h -MoO 3 ) nanobelts prepared by a simple hydrothermal route from peroxomolybdate solution with the presence of sodium nitrate as a mineralizer. During the reaction process, NaNO 3 has been proposed to influence the deoxidation, condensation, and further dehydration of the water-soluble peroxomolybdate precursor for connecting the [MoO 6 ] octahedra with vertex sharing and edge sharing arrangements on determining the generation of metastable phase. The present work comparatively investigates the photochromic and electrochromic behaviors of the resultant hexagonal h -MoO 3 nanobelts and the common thermodynamically stable orthorhombic α-MoO 3 nanobelts. The performances concerning photochromism on two types of MoO 3 nanobelt suspensions show that the photochemical efficiency of h -MoO 3 is more excellent than that of α-MoO 3 under UV light irradiation based on a remarkable coloration phenomenon. And the as-obtained h -MoO 3 nanobelt coated film exhibits a steady electrochromic property in quick response to electrical impulse. Higher structure openness degree in the tunnel structure of h -MoO 3, which could lead to an efficient electron−hole separation and provid larger spatial locations for cation insertion/extraction and diffusion, is suggested to be responsible for its enhanced coloration properties.