Structural study and gas sensing application of nanocrystalline mixed ferrites synthesized by auto-combustion method

The present research work reports the synthesis of nanocrystalline nickel ferrite and its composition with manganese ferrite by employing the citrate-gel auto-combustion route to study the structural properties and gas sensing application. The gas sensing devices were successfully synthesized in the form of pellets to study their response toward the target gases. The stoichiometry of ferrite powders is confirmed by EDAX analysis. The crystallite size, porosity, and other structural parameters were deduced by XRD analysis. The average particle size obtained by TEM measurement was compared with crystallite size. The basic characteristics of spinel ferrites were studied by FTIR analysis. The optical bandgap energy value of samples was found by UV–Vis. DRS analysis. The gas sensing experiment was performed successfully to study the gas response (%) at different gas concentrations (ppm) and temperatures (℃). The maximum sensitivity (S_max) of around 99% was exhibited by Mn_0.8Ni_0.2Fe₂O₄ at different temperatures.