Facile construction of Co3O4 porous microspheres with enhanced acetone gas sensing performances

Large-scale and well-dispersed Co3O4 porous microspheres have been successfully synthesized by a room temperature solution approach followed by the calcination treatment in air. Microstructural characterizations by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) show that as-prepared Co3O4 microspheres with diameters of 800-950 nm are assembled by numerous nanoparticles and present loose porous architectures. When applied as a gas sensing material, Co3O4 porous microsphere based sensor exhibits more rapid response/recovery speed (2 s/5 s) and higher sensitivity towards acetone gas at 180 degrees C compared with ethanol, toluene, formaldehyde, ammonia and benzene gas. Meanwhile, Co3O4 microsphere-based sensors also show superior stability and reproducibility towards acetone gas. The high catalytic activity of Co3O4 specimen and stable and penetrable sensing networks constructed by three dimensional sphere-like loose architectures promote target gas adsorption/desorption, facilitate surface chemical reaction and accelerate electron transfer, thus enormously improving gas sensing dynamics.