Constructing one dimensional Co3O4 hierarchical nanofibers as efficient sensing materials for rapid acetone gas detection

The distinctive Co₃O₄ hierarchical nanofibers (Co₃O₄ HNF) is fabricated by annealing as-prepared PVA/Co(NO₃)₂·6H₂O hierarchical nanofibers, which are synthesized by direct hydrothermal treatment of electrospun PVA/Co(NO₃)₂·6H₂O nanofiber precursors without annealing process. In this way, the morphology, aggregation level and crystallinity of designed Co₃O₄ HNF can be well regulated during hydrothermal process. Microstructural characterization by means of scanning electron microscopy and X-ray diffraction demonstrates that numerous porous nanosheets almost perpendicularly grow on the surfaces of nanofibers, constructing distinctive Co₃O₄ hierarchical nanofibers. Such unique fiber-like hierarchical architectures provide efficient and convenient channels for the transmission of carriers and effectively convert chemical signals into electrical signals. As a result, Co₃O₄ HNF based sensors exhibit enhanced acetone gas sensing response in comparison with the common Co₃O₄ nanofibers (Co₃O₄ NF). Moreover, Co₃O₄ HNF shows rapid response (7 s) and recovery time (1 s) towards 100 ppm acetone gas at an optimal working temperature of 190 °C. This work may open up a facile and feasible approach for constructing hierarchical nanofibers to achieve high performance detection of acetone gas.