Cactus-inspired GO/ZnO sensors for fast and robust acetone sensing properties

Abstract

Fabrication of fast, high-selectivity and reliable gas sensors for real-time monitoring of acetone in exhaled gases remains a key challenge for the development of accurate diabetes diagnosis systems. Inspired by the cactus, in this paper, acetone gas sensor using graphene oxide (GO) with porous zinc oxide (ZnO) nanotube clusters was introduced by room temperature liquid phase method. Porous ZnO nanotubes with lengths of 1∼2 μm formed nanoclusters and were uniformly dispersed on the GO sheets, presenting a specific “cactus-like” three-dimensional structure, which supplied more channels and active sites for the diffuse and adsorption of acetone molecules. The cactus-like GO/ZnO sensor exhibits a high response value of 54.3 (5.9-fold improvement compared to ZnO), fast response/recovery time of 3.8/2.9 s (15.7/19.8 s for ZnO), and robust stability to 50 ppm acetone at 180 °C. Special, the sensor can detect even acetone down to 0.1 ppm with a remarkable response (2.1). Moreover, the adsorption energies of different gases were calculated by density functional theory, which further confirmed the good acetone selectivity of the cactus-like GO/ZnO sensor. The appreciable gas sensing performances are mainly attributed to the unique cactus-like nanostructure with abundant holes and high specific surface area, as well as the heterojunctions between GO and ZnO. This unique biomimetic structure provides a promising strategy for designing acetone gas sensors with high practicality.