Synthesis and characterization of MnFe2O4 nanoparticles for impedometric ammonia gas sensor

Growing concentration of toxic gases in the atmosphere presents a great challenge in the identification of suitable and novel gas sensing materials, with good selectivity at room temperature. This work demonstrates a facile synthesis of MnFe2O4 nanoparticles by solution assisted combustion synthesis. The synthesized materials are characterized by XRD, FTIR, FE-SEM to confirm the crystal structure and surface morphology. The ferromagnetic behavior of prepared MnFe2O4 at room temperature was revealed through VSM analysis. The N-2 adsorption-desorption isotherm and BET surface area analysis confirms the mesoporous nature with the surface area of 33 m(2) g(-1). The room temperature sensing behavior of MnFe2O4 is studied using impedometric technique for analyzing ammonia gas. The prepared MnFe2O4 is robust and shows a sensitivity of 100% for increasing concentration of ammonia vapor. The conductivity increased in the order of 10(2) magnitudes while increasing ammonia concentration. It shows the high selectivity of 83.5% for 10 ppm towards ammonia over other toxic gases like chloroform, etc. The room temperature (303 K) operation, with high sensitivity, selectivity, together with the low cost suggests suitability of developing a new, high power cost-effective ammonia sensor. (c) 2015 Elsevier B.V. All rights reserved.