Synthesis of SnO2 nanoparticles for gas sensing applications

Abstract

SnO2 nanoparticles were synthesized using a hydrothermal method in the presence of the surfactant hydrazine at 100°C for 12 h. X-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (DRS) were employed to characterize the product. The X-ray diffraction (XRD) pattern of the as-prepared sample is indexed to the tetragonal structure of SnO2 and the particle size is 22.4 nm, which is further confirmed by TEM. Analysis of the DRS spectrum showed the band gap of the synthesized SnO2 to be 3.6 eV. The anionic surfactant hydrazine plays a key role in the formation of the SnO2 nanostructures. A probable reaction for the formation of SnO2 nanoparticles is proposed. Gas-sensing properties of the sensor element were tested to various gases, as a function of operating temperature and concentrations of the test gases. The nanocrystalline SnO2 exhibited high response towards H2S gas at an operating temperature 150°C. The selectivity of the sensor elements for H2S against different reducing gases was studied. The results on response and recovery time were also discussed.