A dual-functional highly responsive gas sensor fabricated from SnO2 porous nanosolid

We report here the fabrication of SnO2 thick film and SnO2 porous nanosolid CO gas sensors by using SnO2 nanoparticles and porous nanosolid (PNS). It is found that the thick film sensor fabricated from SnO2 PNS has lower intrinsic resistivity than the one fabricated from SnO2 nanoparticles, and the sensor response of the former is higher than that of the latter. On comparison, the SnO2 PNS sensor, prepared by directly coating Au electrodes on the opposite surfaces of a SnO2 PNS, possesses both lower intrinsic resistivity and higher sensor response to CO gas. Furthermore, the SnO2 PNS sensor also has much lower working temperature, and it can be used as a dual functional gas sensor, i.e., as CO sensor at 300 °C and as CH4 sensor at 400 °C, respectively.