The effect of microstructure on the gas properties of NiFe2O4 sensors: Nanotube and nanoparticle

To explore the effect of structure on gas properties of sensor, hollow nanotubes with the length of 1 μm and the diameter of 100 nm and nanoparticles of nickel ferrite had been synthesized by an effective anodic aluminum oxide (AAO) templates method and hydrothermal method, respectively. Phase composition, structural, morphology characters and specific surface area were measured using X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherm analysis. The results indicated that the nanotubes and nanoparticles were consisted of pure NiFe2O4 phase with homogenous size. The ammonia gas sensing properties of NiFe2O4 nanotubes and nanoparticles based sensors were measured. Based on the results, nanotube gas sensors showed more favorable response than those of nanoparticle ones. And the nanotube gas sensor showed the best response in 100 ppm ammonia gas at 150 °C and favorable repeatability which was related to the higher specific surface area of special porous structure.