Crystalline size- control of SnO2 nanoparticles with tunable properties prepared by HNO3-ethanol assisted precipitation

Abstract SnO 2 nanoparticles were prepared by a novel HNO 3 -ethanol assisted precipitation method. The crystalline size of SnO 2 nanoparticles was controlled based on aqueous solution by varying the molar ratio of HNO 3 and ethanol within the range 0–0.12:0.06–0.18. The obtained SnO 2 nanoparticles were characterized by TG-DSC, FTIR, XRD, TEM, HRTEM, SAED, EDS, UV–Vis, electrical resistance and bulk density measurements as a function of the contents of HNO 3 and ethanol. Results indicated that the SnO 2 nanoparticles with increased contents of HNO 3 and ethanol featured decreased crystalline size, probably related to the increased number of nucleation sites and decreased exothermic amount at the maximum exothermic temperature about 475 °C of the SnO 2 precursor. The SnO 2 nanoparticles revealed bigger energy gap and larger gas response with increased HNO 3 -ethanol additives, which could be ascribed to the Burstein-Moss effect and more active reaction sites due to the small crystalline size. The intrinsic formation mechanism of SnO 2 nanoparticles was proposed based on the formation process of SnO 2 precipitate. Besides, the contents of HNO 3 -ethanol additives had a strong impact on the optical absorption, electrical conductivity and bulk density of SnO 2 nanoparticles.