Synthesis of Crystalline/Amorphous Core/Shell MoO₃ Composites through a Controlled Dehydration Route and Their Enhanced Ethanol Sensing Properties

Considering the specific surface area, flexible structures, high porosity, and a homogeneous and isotropic nature down to the atomic scale possessed by the amorphous nanostructure, an interesting controlled dehydration route has been developed to synthesize the crystalline/amorphous core/shell (C/A-C/S) MoO₃ nanocomposite, in which macroisopolyanion [Mo₃₆O₁₁₂­(H₂O)₁₆]^8– ({Mo₃₆}) was successfully assembled into a one-dimensional connection and underwent a deficient crystallization induced by the prospective infiltrative dehydration process. The as-obtained MoO₃ samples’ affirmative composition and composite structure have been further demonstrated by the XRD, TEM, HRTEM, and Raman spectra measurements. As a result of this special C/A-C/S structure, the MoO₃ composite exhibited high selectivity and a higher sensor response, at a lower working temperature (180 °C) to ethanol gas compared with other 1D MoO₃ micro/nanostructures reported previously.