Engineered spinel–perovskite composite sensor for selective carbon monoxide gas sensing

In the present work, a novel strategy has been adopted to develop highly sensitive and selective carbon monoxide (CO) gas sensor using (x)NiFe2O4 (spinel)–(1 − x)La0.8Pb0.2Fe0.8Co0.2O3 (perovskite) (0 ≤ x ≤ 1) composite nano-powders. These powders were prepared through a citric acid mediated wet chemical pechini route. We have investigated the effect of the inclusion of perovskite phase in the spinel matrix to achieve high sensitivity, selectivity, lowering of the optimum temperature, rapid response and recovery time toward CO sensing. Improvement of these gas sensing parameters are essential to yield smart CO sensing system. We have demonstrated that optimized 25%NiFe2O4–75%La0.8Pb0.2Fe0.8Co0.2O3 composite exhibits excellent sensitivity and selectivity toward CO sensing in operating temperatures ranging between 125 and 175 °C. The plausible reasons for the improvement in gas sensing parameters are discussed.