Vertical SnO2 nanosheet@SiC nanofibers with hierarchical architecture for high-performance gas sensors

Abstract

Increasing demands for detection of harmful gases in harsh environments have stimulated considerable efforts to develop a novel gas sensor with high sensitivity, superior thermal/chemical stability and fast response/recovery rate. In this paper, we report the vertical growth of ultrathin SnO₂ nanosheets (SnO₂ NSs) on quasi-one-dimensional SiC nanofibers (SiC NFs) forming a hierarchical architecture via a simple hydrothermal method. In comparison to pure SnO₂ NSs, the SnO₂ NS@SiC NF hierarchical composite shows an ultrafast response/recovery rate, high sensitivity, and simultaneously excellent reproducibility to various target gases including ethanol, methanol, hydrogen, isopropanol, acetone and xylene, even at high temperature. The response times are less than 5 s with corresponding recovery times <15 s. Furthermore, the SnO₂ NS@SiC NF gas sensor shows a superior sensing selectivity and long-term stability to ethanol. The hierarchical architecture and synergetic effect of the SnO₂–SiC heterojunction as well as plenty of active sites from the vertically ultrathin SnO₂ NSs have critical effect on the superior sensing performance of SnO₂ NS@SiC NFs. This work highlights the possibility to develop a novel high-performance gas sensor for application in harsh environments.