Facile and fast decoration of SnO₂ nanowires with Pd embedded SnO_2-x nanoparticles for selective NO₂ gas sensing

The typical methods used to improve the sensing properties of metal oxide nanowire-based gas sensors include decoration of a metal catalyst on the surface of nanowires or generation of surface defects. In this study, we suggest a process for preparing a Pd metal catalyst surrounded in SnO_2-x with a large number of structural defects on the surface of SnO₂ nanowires for gas sensing applications. Initially, SnO₂ nanowires were prepared using a simple vapor-liquid-solid method and Pd-embedded SnO_2-x-decoration was achieved by flame chemical vapor deposition. Gas sensing studies demonstrated the promising effects of Pd-embedded SnO_2-x-decoration. The underlying sensing mechanism was studied in detail and explained in terms of generation of oxygen defects, catalytic activity of Pd, and formation of heterojunctions in the sensing material. The results of the present study clearly demonstrate the usefulness of this simple and fast approach to significantly enhance the gas sensing properties of metal oxide nanowires.