BiFeO₃/Bi₂Fe₄O₉ Composite Nanofibers for the Enhanced Gas-Sensing Performance Toward n-Butanol

The present study focuses on the synthesis of BiFeO3/Bi2Fe4O9 composite nanofibers via electrospinning, which exhibit enhanced gas-sensing properties toward n-butanol. Notably, the sensors based on 11.3-BFO nanofibers demonstrate a remarkable response of 40.8–100-ppm n-butanol, representing an approximately 3.4-fold improvement compared to pure BiFeO3 nanofibers. Additionally, the 11.3-BFO gas sensor exhibits a rapid response time (18 s) and recovery time (37 s) when operated at a temperature of 150 °C. It also exhibits excellent selectivity, good repeatability, and long-term stability. The improved gas-sensing performance can be attributed to the formation of heterojunctions and a more textured surface, thereby indicating the potential application of BiFeO3/Bi2Fe4O9 composite nanofibers as a gas sensor for n-butanol detection. This study further validates the efficacy of constructing heterojunctions in improving the gas-sensitive properties of metal-oxide–semiconductor, thereby providing valuable insights for synthesizing and investigating heterojunctions.