Regulation of O-vacancy and heterojunction structure in MOF-derived Fe2O3-Co3O4 enhancing acetone sensing performance

In this study, a hierarchical Fe 2 O 3 -Co 3 O 4 heterojunction with abundant oxygen vacancies was fabricated by a MOF-assisted strategy combing with a thermal treatment process. The morphology, nanostructure and other properties of the synthesized samples were comprehensively investigated by related characterizations. The results display that the Co 3 O 4 modified with Fe 2 O 3 nanorod exhibits an admirable mesoporous structure and abundant oxygen vacancies. In addition, the gas sensing devices were constructed by as-prepared samples and demonstrated that the gas sensor based on Fe 2 O 3 -Co 3 O 4 composites shows excellent gas sensitivity of 91.5 towards 100 ppm acetone at a working temperature of 200 °C, with a short response-recovery time of 20/21 s. Meanwhile, the sensor possesses good reproducibility and long-term stability (over 30 days), and outstanding selectivity towards acetone gas. Exploration into a convincing gas sensing mechanism confirms that fabricating of p-n heterojunction architecture, regulating of oxygen vacancies and designing of mesoporous structure synergistically induced the excellent gas sensing performance. Therefore, this work can offer a promising strategy to enhance acetone sensing response of Fe 2 O 3 -Co 3 O 4 in practical applications.