Investigations on lanthanum iron cobalt oxide thin film as selective carbon monoxide sensor

Abstract A highly sensitive and selective carbon monoxide sensor has been developed using LaFe0.8Co0.2O3 (LFCO) perovskite thin-film sensing element. A modified sol-gel approach was employed to develop the nanostructured thin film. Through proper utilization of the perovskite surface’s catalytic properties and the benefits of accessible microstructural control in a thin film sensing element, selective carbon monoxide sensing could be achieved. For 500 ppm CO, a response of ~ 87% with a response time of ~ 100 s has been reported at 225 °C. The LFCO sensor is selective to CO over a wide temperature range of 325–175 °C. High selectivity coefficients for carbon monoxide has been reported for H2 (κ ~ 4.53), C4H10 (κ ~ 6.62), CH4 (κ ~ 86.00) and NOx (κ ~ ∞ ) at 225 °C. The high selectivity to CO for LFCO sensor has been attributed to the low metal–oxygen binding energy, favorable d-orbital electronic configuration of the transition metal cations and the surface composition of the perovskite.