title: Freestanding 3D mesoporous Co₃O₄@carbon foam nanostructures for ethanol gas sensing.
abstract: Metal oxide materials have been widely used as gas-sensing platforms, and their sensing performances are largely dependent on the morphology and surface structure. Here, freestanding flower-like Co3O4 nanostructures supported on three-dimensional (3D) carbon foam (Co3O4@CF) were successfully synthesized by a facile and low-cost hydrothermal route and annealing procedure. The morphology and structure of the nanocomposites were studied by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive spectroscopy, and scanning electron microscopy (SEM). The SEM characterizations showed that the skeleton of the porous carbon foam was fully covered by flower-like Co3O4 nanostructures. Moreover, each Co3O4 nanoflower is composed of densely packed nanoneedles with a length of ~10 μm, which can largely enhance the surface area (about 286.117 m(2)/g) for ethanol sensing. Gas sensor based on the as-synthesized 3D Co3O4@CF nanostructures was fabricated to study the sensing performance for ethanol at a temperature range from 180 to 360 °C. Due to the 3D porous structure and the improvement in sensing surface/interface, the Co3O4@CF nanostructure exhibited enhanced sensing performance for ethanol detection with low resistance, fast response and recovery time, high sensitivity, and limit of detection as low as 15 ppm at 320 °C. The present study shows that such novel 3D metal oxide/carbon hybrid nanostructures are promising platforms for gas sensing.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Minmin
authors.initials: M
authors.lastname: Liu
authors.forename: Shuijian
authors.initials: S
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D000431:Ethanol / Q000032:analysis*; D005740:Gases / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures; D010087:Oxides / Q000737:chemistry*; D016062:Porosity
chemical_list: D005740:Gases; D010087:Oxides; D003035:Cobalt; D000431:Ethanol; D002244:Carbon; C060728:cobalt oxide