Nanostructure-Governed Methane Sensing and Response Mechanism in Engineered LaFeO3

Methane, a highly hazardous gas mixture when exposed to open flames, is commonly encountered in coal mines. Its primary component is CH4, making the detection of its concentration, especially under diverse environmental conditions, highly significant. In this study, La0.7Gd0.3Fe0.9Co0.1O3 nanomaterials were prepared using an ultrasound-assisted hydrothermal method. Through dual-site synergistic regulation involving Gd doping at the A-site and Co doping at the B-site, rapid detection of CH4 at low temperatures was achieved. At 150 ∘C, the sensor demonstrated a significantly enhanced response to 100 ppm CH4, with a sensitivity of 10.22. This value represents an approximately tenfold improvement over that achieved with pure LaFeO3. In addition, the sensor responded rapidly to the gas exposure within 6.3 s and recovered within 5.4 s, respectively, at the same gas concentration. Such swift recovery capabilities enable reliable detection across multiple environmental conditions. Moreover, the sensor not only shows excellent repeatability but also maintains a high response value of 9 even under highly humid conditions (95% RH). The performance enhancement is attributed mainly to lattice distortion induced by A-site doping and the increased active sites provided by B-site doping. The development of this sensor lays a foundation for future CH4 detection and industrial safety applications.