Cobalt-Doped LaFeO₃ Nanomaterials for High-Performance Formaldehyde Sensing in Vehicle Air Quality Monitoring

Formaldehyde detection in vehicular environments has emerged as a critical research area due to growing concerns over indoor air pollution and its adverse health effects. This study presents a novel formaldehyde sensor based on cobalt-doped lanthanum ferrite (Co-LaFeO 3 ) nanomaterials, synthesized via a citric acid complexation method. The structural, morphological, and compositional properties of the prepared materials were thoroughly characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Gas-sensing performance evaluations revealed that the Co-LaFeO 3 sensor exhibits exceptional sensitivity, selectivity, and stability toward formaldehyde vapor at an optimal operating temperature of 300 °C. The sensor demonstrated a high response magnitude, excellent linearity across a broad concentration range (10–700 ppm), and rapid response/recovery kinetics (37.4 s/36.6 s). The enhanced performance is attributed to Co doping, which induces lattice distortion, increases oxygen vacancies, and improves catalytic activity, thereby facilitating efficient gas adsorption and surface reactions. Additionally, the sensor maintained consistent performance over multiple cycles, indicating robust repeatability and long-term stability. These findings suggest that Co-LaFeO 3 is a promising candidate for next-generation formaldehyde sensors in automotive applications, offering real-time monitoring capabilities for in-vehicle air quality. This work not only advances the development of high-performance gas sensors but also contributes to mitigating health risks associated with vehicular air pollution.