Facile fabrication of NiO foam@Sn-doped In2O3 nanowire heterosturctures for highly sensitive ethylene glycol gas sensors at low temperatures

Abstract

Ethylene glycol is odorless and harmful to human beings. However, the high operating temperature and the low gas response of the ethylene glycol sensors limit their wide applications. Herein, p-type nickel oxide foam/ n-type tin-doped indium oxide nanowires composite (NTO) has been fabricated for ethylene glycol gas sensing. The NTO composite was prepared by complete oxidation of Ni foam at high temperature, then Sn-doped indium oxide (ITO) nanowires were grown on NiO foam by chemical vapor deposition. The assembled NTO sensor exhibits a unique response (Rg/Ra=160.72) to 100 ppm ethylene glycol at a low temperature of 125 ℃, and a fast response/ recovery time (8.7 s/ 19.3 s). This excellent gas-sensitive performance of NTO sensors can be attributed to the formation of p/n heterojunctions and the In and Sn doping of NiO during ITO growth. This fabrication method provides an effective strategy for building NiO-based heterostructures for high-performance gas sensors.