Surfactant-free solution phase synthesis of monodispersed SnO2 hierarchical nanostructures and gas sensing properties

Abstract

In this work, SnO₂ hierarchical nanostructures were successfully prepared via a simple and surfactant-free hydrothermal process starting from stannous sulfate (SnSO₄) and trisodium citrate dihydrate (Na₃C₆H₅O₇·2H₂O) in a suitable ethanol–water system. TEM and HRTEM images showed that the obtained SnO₂ products are uniform, well-dispersed, and have spherical architectures, composed of tiny primary nanocrystals, and the diameters are about 50 nm. It was found that the amount of Na₃C₆H₅O₇·2H₂O and the volume ratio of ethanol and water played important roles in determining the final morphologies of the products. The gas sensing results indicated that the sensor made from porous SnO₂ nanostructures calcined at 400 °C exhibited excellent gas sensing performance to butanol at the low temperature compared with those under higher calcination temperature and commercial SnO₂. The SnO₂ hierarchical nanostructures possess uniform size and large surface areas, making them ideal candidates for more potential applications such as battery electrodes and as opto-electronic devices.