Different Co3O4 mesostructures synthesised by templating with KIT-6 and SBA-15 via nanocasting route and their sensitivities toward ethanol

Two types of mesoporous Co3O4 denoted as Co3O4-k and Co3O4-s were successfully synthesised using cubic KIT-6 and hexagonal SBA-15 as hard templates, respectively. The results of small-angle X-ray diffraction, nitrogen adsorption-desorption, and transmission electron microscopy demonstrate that the synthesised Co3O4-k and Co3O4-s display three-dimensional cubic mesostructures and two-dimensional hexagonal mesostructures, respectively. The sensor based on Co3O4-k exhibits better response and recovery behaviour and much higher sensitivity toward ethanol compared to those based on Co3O4-s, although both samples have similar specific surface areas. It is concluded that Co3O4-k composed of the three-dimensional intersecting channels possess high utilisation and accelerating gas diffusion in sensing materials. Furthermore, large charge transfer and adsorption energy of ethanol to Co3O4(110) at the surface of Co3O4-k is revealed through first-principles calculations. These results finally account for the superior sensing performance exhibited by the Co3O4-k than Co3O4-s sensors. (C) 2016 Elsevier B.V. All rights reserved.