Modification of coral-like SnO2 nanostructures with dense TiO2 nanoparticles for a self-cleaning gas sensor

A coral-like SnO2 nanostructure densely-modified with TiO2 nanoparticles was reported for developing a self-cleaning gas sensor. The density of the TiO2 nanoparticles in the TiO2/SnO2 nanocomposites can be greatly improved via a plasma-based modification (PM) on SnO2/carbonaceous precursors before introducing Ti sources. In gas-sensing measurements, benzene and toluene were employed as target analytes. The results show that the gas sensor based on the TiO2/SnO2 nanostructures with PM exhibits a remarkably improved stability after detecting for many cycles compared with the ones based on TiO2/SnO2 without PM and pure SnO2 nanostructures. The mechanism for the stable performance has been demonstrated from the self-cleaning degradation of TiO2 nanoparticles towards the adsorbed organic species. Furthermore, the recognizable ability towards targets was also investigated by using some algorithmic recognition methods including principal component analysis (PCA) and nonnegative matrix factorization (NMF). The fascinating gas-sensing properties including enhanced stability, sensitivity, and recognizable ability enable the presented TiO2/SnO2 nanocomposites to be a promising candidate for fabricating self-cleaning gas sensor which can be applied for detecting environmental gas contaminants. (C) 2012 Elsevier B.V. All rights reserved.