Facile one-step hydrothermal synthesis of SnO2 microspheres with oxygen vacancies for superior ethanol sensor

This work reports a facile one-step hydrothermal method to synthesize the microsphere SnO2 particles without using any organic agent. The experiment results show that the obtained SnO2 microspheres consisting number of nanocrystalline particles of 2–5 nm in size. Oxygen vacancies are also existing on the surface of the SnO2 microspheres. The as-prepared SnO2 microspheres possess mesoporous structure of remarkably high specific surface area (111.27 m2g-1). The gas sensing properties of the as-prepared SnO2 microspheres for ethanol was investigated. The response and recovery time of SnO2 sensor surprisingly reached to 3 s and 24 s respectively under 100 ppm flow of ethanol at an operating working temperature of 230 °C. The response of sensor for 100 ppm of ethanol is enhanced to 24.9 at 230 °C. The excellent ethanol-sensing performance of the fabricated sensor has been attributed to its small grain size, high specific surface area and number of oxygen vacancies of SnO2. These results indicating that the SnO2 microspheres obtained in this work is a promising and excellent ethanol-sensor material.