Loose Ag-Doped LaFeO 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.