Loose Ag-Doped LaFeO₃ Nanotubes-Based Gas Sensor for Excellent Acetic Acid Sensing

The efficient and reliable monitoring of acetic acid (CH3COOH) is significant to environmental protection and human healthcare. LaFeO3 is a potential sensing material for CH3COOH with its good sensitivity and high plasticity. To further improve the sensing properties of LaFeO3 to meet the requirements of applications, we successfully utilized the facile electrospinning technique to fabricate a series of CH3COOH-sensitive Ag-doped (0–5 mol%) LaFeO3 nanotubes. The systematic characterization shows that the appropriate content (4 mol%) of Ag doping can effectively ameliorate the material morphology to realize loose porous structures. Meanwhile, the sensitization effect of Ag and ameliorated morphology significantly enhance the gas-sensing properties of LaFeO3 to CH3COOH vapor. The optimal Ag-doped LaFeO3 (4 mol%) loose nanotubes-based gas sensor results in a detection limit of 0.5 ppm and 3.6-fold enhancement of the response to 100-ppm CH3COOH compared with the pure LaFeO3 compact nanotubes at a low operating temperature (150 °C). It also exhibits excellent selectivity to CH3COOH and good long-term stability. Therefore, Ag-doped LaFeO3 can be regarded as a promising material for sensing CH3COOH in practical applications. Finally, the mechanism of enhanced gas-sensing properties is discussed.