Hollow Pd-Ag Composite Nanowires for Fast Responding and Transparent Hydrogen Sensors
By Jang, Ji-Soo; Qiao, Shaopeng; Choi, Seon-Jin; Jha, Gaurav; Ogata, Alana F; Koo, Won-Tae; Kim, Dong-Ha; Kim, Il-Doo; Penner, Reginald M.
Published in ACS Applied Materials & Interfaces
Abstract
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