1D N-type SnO₂ nanofibers coexisted with P-type Co₃O₄ cubes for highly selective acetone sensor

1D n-type SnO₂ nanofibers coexisted with p-type Co₃O₄ particles were synthesized by electrospinning with subsequent hydro-thermal process. The morphology and composition of Co₃O₄/SnO₂ were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). XRD patterns showed that the synthesized Co₃O₄/SnO₂ were assigned to cubic Co₃O₄ and tetragonal rutile structure of SnO₂ without any other impurity peaks. A possible growth mechanism was proposed to describe the formation of hierarchical SnO₂ nanofibers coexisted with Co₃O₄ cubes. The Co₃O₄/SnO₂ compound exhibited a relatively highly selective response to acetone and stable acetone sensing performance after a long period of aging. The Co₃O₄/SnO₂ compound had a p-type response. It may be ascribed to the high coverage of p-type Co₃O₄ on n-type SnO₂. The excellent acetone sensing properties of Co₃O₄/SnO₂ nanostructures may be attributed to p-n junctions between Co₃O₄ and SnO₂ nanograins as well as the unique coexistence structure of nanofibers and cubes. (paper)