Ferroelectric Perovskite BiFeO₃-Modified Cubic In₂O₃ With Improved Gas-Sensing Properties for n-Butanol

The toxicity and flammability of n-butanol, as the volatile organic compounds (VOCs), have endangered human life and the production environment. Therefore, there is an imperative requirement for highly sensitive gas sensors for the detection of n-butanol. Ferroelectric perovskite BiFeO3 materials with special crystal structure and remarkable catalytic effect are prospective in the metal-oxide–semiconductor (MOS) gas sensors field. In this work, BiFeO3-modified cubic In2O3 composites are prepared to address the insufficient gas-sensing properties of traditional In2O3 sensors for n-butanol. The response value of the proposed BiFeO3/In2O3 gas sensor to 10-ppm n-butanol is 24.5 at $240~^{\circ }$ C, which is twice that of pure In2O3. In addition, the BiFeO3/In2O3 sensor exhibits a detection limit of 100 ppb, good long-term stability, and selectivity. The improvement in gas-sensitive properties is due to the heterojunctions between BiFeO3 and In2O3, rich oxygen defects, and strong catalysis of BiFeO3, demonstrating the significant importance of the sensor proposed in this study in industrial and environmental fields.