Low-temperature detection and excellent selectivity of ethanol using LaFeO3 gas sensors with dual regulation of doping and non-stoichiometry

ABO 3 -type gas sensors for ethanol gas-sensing remain a significant challenge. In this paper, porous microspheres of La 0.9 Fe 1-x Co x O 3 (x = 0, 0.05, 0.1, 0.15, 0.2) were synthesized via a ultrasonic-assisted hydrothermal method. The materials were characterized with various techniques to determine their phase structures, morphologies, electrochemical properties, and sensing abilities. For all investigated sensors, La 0.9 Fe 0.85 Co 0.15 O 3 exhibited a response value of 50.445 for 100 ppm ethanol gas at 200 °C (RH = 35 %), which is over eight times higher than that of LaFeO 3 under the same conditions. In addition to its high response to ethanol, La 0.9 Fe 0.85 Co 0.15 O 3 has excellent selectivity, humidity resistance (35–95 % RH), and a fast response/recovery time (18/9 s). Further analyses demonstrate that the synergistic effect of A-site cation defects and Co-doping plays a pivotal role in enhancing sensing performance by effectively increasing oxygen vacancy content and adsorption energy. This work presents an effective approach for developing high-performance ethanol gas sensors based on LaFeO 3 .