Facile Route to Polycrystalline Pd/ ${rm SnO}_{2}$ Nanowires Using ZnO-Nanowire Templates for Gas-Sensing Applications

摘要

Polycrystalline Pd/${rm SnO}_{2}$ nanowires have been fabricated using ZnO-nanowire templates by the combination of thermal evaporation, pulsed-laser deposition, and dc sputtering. The rutile ${rm SnO}_{2}$ nanocrystals were grown on the ZnO nanowire with Volmer–Weber mode due to the large lattice mismatch. The discrete Pd nanocrystals were also successfully deposited onto the nanostructures, which were identified by high-angle annual dark field scanning transmission electron microscopy. The 1-D polycrystalline ${rm SnO}_{2}$ coatings with catalytically active Pd layer can effectively detect air-diluted ${rm H}_{2}{rm S}$. The sensing behaviors can be understood by a Langmuir isotherm absorption model. The fabrication method provides a general strategy to prepare 1-D metal-oxide conductometric gas sensors.