Gas sensing properties of hematite nanoparticles synthesized different techniques.

The synthesis techniques used for metal oxide semiconductors strongly influence their chemical, physical and gas sensing characteristics. In this context, hematite (α-FeO) nanoparticles (NPs) were synthesized using two different techniques, namely, sol-gel (named H) and Pechini sol-gel (named H). The average crystallite size and surface area were 15 nm and 76 m g and 20 nm and 57 m g for H and H, respectively.

Ammonia gas sensors based on undoped and Ca-doped ZnO nanoparticles.

Due to its large use in different industrial sectors, high toxicity, and corrosion, the demand for sensing techniques towards ammonia gas has become urgent. In this study we report on the sensing performances of a conductometric sensor for NH gas based on Ca-doped ZnO nanoparticles with different calcium concentrations (0, 1, and 3 at%) synthesized using the sol-gel process under supercritical dry conditions of ethanol. All samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy.