| 초록 |
Pd based alloy materials with hollow nanostructures are ideal hydrogen (H2) sensor building blocks because of the ultra-high surface area afforded by this architecture. In this work, for the first time, we report a simple fabrication process for preparing hollow Pd-Ag alloy nanowires (Pd@Ag HNWs) by using the electrodeposition of lithographically patterned silver nanowires and followed galvanic replacement reaction (GRR) to form palladium. By controlling the GRR time of aligned Ag NWs within an aqueous Pd2+-containing solution, the compositional transition and morphological evolution from Ag NWs to Pd@Ag HNWs simultaneously occurred, and the relative atomic ratio between Pt and Ag was controlled. Interestingly, a GRR duration of 17 h transformed Ag NWs into Pd@Ag HNWs, that showed enhanced H2 response and faster sensing response time - reduced 2.5-fold – as compared to silver nanowires subjected to a shorter GRR period of 10 h. Furthermore, Pd@Ag HNWs patterned on the colorless and flexible polyimide (cPI) substrate showed highly reversible H2 sensing characteristics. To further demonstrate the potential use of Pd@Ag HNWs as sensing layers for all-transparent, wearable H2 sensing devices, we patterned the Au NWs perpendicular to Pd@Ag HNWs to form heterogeneous grid-type metallic NWs electrode which showed reversible H2 sensing properties in both bent and flat state. |
