Nanocatalytic effects in Gold/Tin functionalized tin oxide nanowires for enhanced co sensing

Tin oxide (SnO₂) nanowires were synthesized by a molecule based chemical vapour deposition process and the metallic additives Sn and Au were incorporated by treating nanowires in the mixture of Argon and O₂ plasma. Tin inclusion in the SnO₂ nanowires were achieved by preferential etching of the lattice oxygen atoms from the surface of SnO₂ nanowires through the plasma treatment, which lead to chemically directed synthesis of Sn⁰/ SnO₂ nanocomposites. However, Gold incorporated nanowires were obtained by treating the Au sputtered samples (5-13 nm) at low plasma energy to induce nucleation of Au nanocrystals on SnO₂ backbone. Investigations on Carbon-monoxide (CO) sensing behaviour of SnO₂ nanostructures as a function of surface structure, composition and electronic properties are reported. Metal-functionalized nanowires showed better sensitivity for CO at lower operating temperature and exhibited higher transduction towards altering gas atmospheres attributed to a spill-over effect in Au incorporated tin oxide nanowires (AuTO), whereas the surface valence dynamics (Sn⁰/ Sn²⁺/ Sn⁴⁺) is responsible for higher sensitivity of Sn incorporated system (SnTO).