Regulation of N-type In2O3 Content on the Conductivity Type of Co3O4 Based Acetone Sensor

Abstract

Abstract A double-jet electrospinning method was adopted to fabricate In2O3/Co3O4 nanofibers (NFs). The sensitivity of In2O3/Co3O4 NFs and In2O3 NFs were compared and analyzed, and the morphology, structure, chemical composition, and gas-sensing properties of the samples were comprehensively characterized. The results show that the introduction of Co3O4 can improve the response of In2O3/Co3O4 to acetone, to 29.52 (In2O3/Co3O4) and 12.34 (In2O3) to 200 ppm acetone at 2000°C, respectively. In addition, the doping of Co3O4 was found to reduce the optimum working temperature of pure In2O3 from 275°C to 200°C. The composite of Co3O4 and In2O3 not only enhances the sensing performance, but also leads to a conversion of p-n conductivity type. The phenomenon of the p-n transition is relevant to operating temperature and proportion of In2O3 and Co3O4. While the enhanced acetone sensing properties of In2O3/Co3O4 NFs may be attributed to the p-n heterojunction between n-type In2O3 and p-type Co3O4 crystalline grains, which promotes the electron migration. The synergistic effects between In2O3 and Co3O4 and the large specific surface area of NFs additionally contribute to the improvements of acetone sensing performance.