Drastic improvement of sensing characteristics in SnO2 nanowires by functionalizing with Pt

We fabricated SnO2/Pt core-shell nanowires by means of a two-step process, in which Pt layers were sputtered onto the surface of networked SnO2 nanowires. For Pt-functionalization, we have synthesized the SnO2-Pt core-shell nanowires by depositing Pt layers using a sputtering method on bare SnO2 nanowires, subsequently annealing and thus transforming the continuous Pt shell layers into Pt nanoparticles. The NO2 gas sensing test demonstrated the ability of the Pt functionalization to attain the higher sensitivity and faster response than bare SnO2 nanowires. The possible mechanisms for improvment of the sensing properties by Pt-functionalization were discussed.