Structure and electrochemical property of single-crystal alpha-MoO3 microbelts synthesized by a solid-state reaction

In this paper, we report the simple and cost-effective synthesis of alpha-MoO3 microbelts with side lengths on the centimeter or millimeter scale by one-step sintering using MoO3 powder. Transparent and flat microbelts revealing (0k0) plane facets cleaved preferentially along the [001] direction are formed without the use of supporting substances in air. Atomic force microscopy and high-resolution transmission electron microscopy analyses confirm that a single-crystal microbelt composed of stacked bunches of alpha-MoO3 sheets is synthesized. The effect of the synthesis conditions on the structure and size of the alpha-MoO3 microbelts is systematically investigated by varying the residual time during sintering and the amount of the source powder. Finally, we demonstrate the electrochemical properties of the single-crystal alpha-MoO3 microbelt in an acidic solution; the microbelt exhibits a variation in transmittance with the application of a potential, implying that it is electrochromic and possesses ion-storage capacity, making it promising for application in supercapacitors. Our study proposes a novel and facile method for the large-scale preparation of alpha-MoO3 microbelts, which will open up new avenues in the field of electrochemical devices.(C) 2022 Elsevier B.V. All rights reserved.