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

• Published in: Journal of alloys and compounds 2021-12, Vol.884, p.161161, Article 161161
• Main Authors: Bhowmick, T., Nag, S., Majumder, S.B.
• Format: Article
• Language: English
• Subjects: Carbon monoxide; Cobalt oxides; Kinetic analysis; Lanthanum; Lanthanum iron cobalt oxide; Perovskites; Response time; Selective sensing; Selectivity; Sensors; Sol-gel processes; Thin film; Thin films; Transition metals
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.161161

•Selective carbon monoxide gas sensing.•Lanthanum iron cobalt oxide thin film sensor.•Effect of thin film thickness variation on gas sensing.•Kinetic analysis of conductance transients. 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.