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

Abstract

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) MoO 3 nanocomposite, in which macroisopolyanion [Mo 36 O 112 (H 2 O) 16 ] 8− ({Mo 36 }) was successfully assembled into a one-dimensional connection and underwent a deficient crystallization induced by the prospective infiltrative dehydration process. The as-obtained MoO 3 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 MoO 3 composite exhibited high selectivity and a higher sensor response, at a lower working temperature (180 °C) to ethanol gas compared with other 1D MoO 3 micro/ nanostructures reported previously.

Diverse Adsorption/Desorption Abilities Originating from the Nanostructural Morphology of VOC Gas Sensing Devices Based on Molybdenum Trioxide Nanorod Arrays

“…The orientation direction of the ultrafine nanorods in this work is [100], [43] the (010) facet lies in the side of the nanorods, which is very readily for the adsorption and subsequently intercalation of H + ions, as shown in Figure 4a,a-2. When the VOCs, e.g., EtOH, were adsorbed onto the surface of the MoO 3 nanorod arrays, the O H bond of the adsorbed EtOH dissociated heterolytically to yield ethoxide groups and hydrogen as follows [51] …”

Hierarchical nanostructured WO3–SnO2for selective sensing of volatile organic compounds

“…The details on LOD calculation is provided as supporting information. [27,42,43,44,45,46,47,48,49,50] The sensing results revealed an apparent temperature-dependent selectivity towards the VOCs as shown in Figure 7 i.e. This suggests that these sensors can be used to detect trace levels of VOCs (except acetone which requires detection ability of ~1 ppm to be used) for biomedical applications and thus are suitable for breath analysis.…”

“…The response of the chemoresistive sensors were calculated using equation (1). 40 Further study is needed to find the exact cause of such instability. To explore the optimum performance of different sensor materials, temperature profiles of each of them were carried out for all the VOCs.…”

A non-template approach to fabricate mesoporous alumina with predefined morphology by solid-state transformation of Al-based metal–organic frameworks

“…In particular, particles with 30 unusual morphology have received great attention because of their potential for extraordinary properties arising from the unusual shape. [6][7][8][9] Therefore, the synthesis of nanostructured alumina with controllable structure and morphology has attracted attention in recent years. 35 Generally, alumina is obtained by dehydration of boehmite (γ-AlOOH) at high temperature, and the morphology and nanostructure of precursor can be retained during this process.…”