Facile control of C₂H₅OH sensing characteristics by decorating discrete Ag nanoclusters on SnO₂ nanowire networks

The effect of Ag decoration on the gas sensing characteristics of SnO ₂ nanowire (NW) networks was investigated. The Ag layers with thicknesses of 5-50 nm were uniformly coated on the surface of SnO₂ NWs via e-beam evaporation, which were converted into isolated or continuous configurations of Ag islands by heat treatment at 450 °C for 2 h. The SnO₂ NWs decorated by isolated Ag nano-islands displayed a 3.7-fold enhancement in gas response to 100 ppm C₂H₅OH at 450 °C compared to pristine SnO₂ NWs. In contrast, as the Ag decoration layers became continuous, the response to C₂H ₅OH decreased significantly. The enhancement and deterioration of the C₂H₅OH sensing characteristics by the introduction of the Ag decoration layer were strongly governed by the morphological configurations of the Ag catalysts on SnO₂ NWs and their sensitization mechanism.