One-step electrospun SnO2/MOx heterostructured nanomaterials for highly selective gas sensor array integration

It is a challenge to effectively detect the components of a gas mixture using metal oxide sensors which are easily fabricated and inexpensive. In this work, heterostructured SnO2/MOx (i.e. M=Zn, Ga and W) nanotubes (NTs) and nanofibers (NFs) are synthesized via a one-step electrospinning technology and subsequent calcination for use in gas sensors. In specific, compared with pure SnO2 NTs, SnO2/ZnO NTs show an enhanced response to 100 ppm ethanol and acetone, while SnO2/Ga2O3 NTs show an obviously higher response to 100 ppm ethanol and SnO2/WO3 NFs show an optimal response to 100 ppm xylene. All these sensors are selective in the presence of typically interfering gases such as formaldehyde, benzene and toluene. As a proof-of-concept, sensor arrays constructed using these three sensors precisely detected the gas mixtures of ethanol, acetone and xylene by means of matrix manipulation, delivering a superior accuracy of < 9% deviation for the gas concentration of 10 ppm and 20 ppm and < 38% for the concentration of 5 ppm. These results show the possibility of improved selectivity in detecting gas mixtures using heterostructured gas-sensing materials for sensor arrays