An olive-shaped SnO2 nanocrystal-based low concentration H2S gas sensor with high sensitivity and selectivity

Abstract

Olive-shaped SnO₂ nanocrystals were synthesized successfully via a facile hydrothermal route, using tin dichloride hydrate, oxalic acid dihydrate and polyvinylpyrrolidone as reaction precursors, and showed great potential in the large-scale preparation of SnO₂ nanocrystals. The prepared SnO₂ nanocrystals were characterized using XRD, XPS, SEM, TEM and HRTEM, and showed well-defined olive-shaped tetragonal single-crystals with irregular exposed facets. The growth mechanism of the olive-shaped SnO₂ nanocrystals was considered after investigating the experimental conditions and reaction time. Due to the abundant active sites on the irregular surfaces, the gas sensing performance of the prepared SnO₂ nanocrystals exhibited great gas sensing properties, including high sensitivity, selectivity and stability towards H₂S with a very low detection limit (less than 0.5 ppm), revealing their great potential in commercial applications for H₂S gas detection.