Facile preparation of SnO2/NiO composites and enhancement of sensing performance to NO2

The SnO2/NiO nanocomposites were successfully prepared by a facile co-calcination method. The structure and the property of the composites were characterized by XRD, FESEM, HRTEM and XPS. The sensing test results indicate that the SnO2/NiO nanocomposite with molar ratio of 4:1 not only exhibits the highest response to 500 ppb NO2, which is 8 times and 13 times higher than that of SnO2 and NiO, respectively, but also has excellent selectivity, outstanding stability and trend of linear response to low concentrations of NO2 at relatively low operating temperature of 80 degrees C. The mechanism of enhancing sensing properties was also discussed in detail, which is attributed to the formation of p-n heterojunction at the interface between SnO2 and NiO, leading to the significant increase of depletion layer thickness at interface. (C) 2017 Published by Elsevier B.V.