Effect of annealing temperature on acetone gas sensor properties based on Ni0.9Co0.1Fe2O4 nanoparticles synthesized by microwave assisted combustion method

In this work firstly Nickel Ferrite (NiFe2O4) nano particles (pure and 10% Cobalt doped-) were synthesized by microwave assisted combustion method. Some disks with radius of 2.5 cm were made by NiFe2O4 and Ni0.9Co0.1Fe2O4 nanoparticles. The prepared disks were annealed at 600 °C, 650 °C and 700 °C for 4 hours. The structural and surface morphology of the samples were studied using X-ray diffraction (XRD) and field emission scanning microscope (FESEM). XRD Spectra indicated the formation of spinel phase. The gas sensing properties of the samples were investigated in presence of 2500ppm acetone gas. The results of this work were shown that as grown samples (pure and doped without annealing) have a higher sensitivity at operating temperature of 250°C. Although, the sensitivity of as grown NiFe2O4 was also higher than as grown Ni0.9Co0.1Fe2O4 sample. Moreover, the sensitivity of the samples was significantly affected by the operating temperature of the gas sensor. Comparison of the results showed that as grown pure Nickel Ferrite is more suitable sample for acetone gas sensing.