Acid vapor oxidation growth of SnO2 nanospheres with ultra-high sensitivity to ethanol detection at low temperature

Abstract

A facile acid vapor oxidation (AVO) method has been developed to grow highly round SnO2 nanospheres from 400 nm metal Sn thin films. This synthesis approach is able to directly grow nanostructures from a substrate in a simple reaction system involving the reaction of Sn film with the vapor generated from a hydrochloric acid solution in a Teflon-lined autoclave. A possible growth mechanism for the interesting SnO2 nanospheres has been proposed based on a series of time-dependent experiments. As-prepared SnO2 nanospheres have diameters around 150 nm. The influence of reacting time on the gas sensing properties of SnO2 was investigated by the detection of ethanol gas. The as-obtained SnO2 nanospheres are ultrasensitive to ethanol with a response of 1.49–50 ppb of ethanol at the low optimal working temperature of 170 ℃, which shows the promising candidates for high performance chemical sensors. This work offers a facile, shape-controlled, and efficient route to synthesize complex SnO2 nanospheres for gas detection with high performance, including ultrahigh sensitivity, good selectivity, and reversibility.