Improving ethanol sensitivity of ZnSnO3 sensor at low temperature with multi-measures: Mg doping, nano-TiO2 decoration and UV radiation

Abstract

A kind of ZnSn(OH)6 crystalline precursor composed of micro- and nano-sized particles with two different morphologies was synthesized by co-precipitation method with the presence of triethanolamine (TEOA) as functional reagent. Zn1-xMgxSn(OH)6 samples (0≤x≤0.5) were prepared by doping Mg2+ ions in the synthesis process of ZnSn(OH)6 precursor. Experimental results reveal that both the morphology and size of ZnSn(OH)6 particles can be changed by TEOA and Mg2+ ions, but not changed by dehydration at high temperature with the formation of Zn1-xMgxSnO3 samples. When x is 0.1, the effect of Mg2+ ions on the morphology and size of ZnSn(OH)6 particles is not remarkable, but the ethanol sensitivity of the resulting ZnSnO3 sample at a low temperature of 80 °C is significantly improved by Mg2+ ions at the conditions of nano-TiO2 decoration and UV radiation. The ethanol response of the composite sample (ZM0.1SO–T10) is as high as ca. 149 at 500 ppm concentration, and its corresponding response and recovery time is about 4 s and 80 s, respectively. Furthermore, the sensor with ZM0.1SO–T10 also shows a good selectivity and long-term stability. Possible reasons for the superior ethanol sensitivity at low temperature were discussed.