Decoration of Pd nanoparticles on ZnO-branched nanowires and their application to chemical sensors

We have coated zinc-oxide (ZnO)-branched tin oxide (SnO2) nanowires with a Pd shell layer via a sputtering method and subsequently investigated the effects of thermal annealing. By the thermal annealing, the Pd shell layers were agglomerated to form the nanoparticles, being comprised of the cubic Pd phase. Sensing measurement in terms of NO2 gas revealed that the morphology of the Pd nanoparticles affected the sensing capability, in that the abundant and dense Pd nanoparticles obtained at certain temperatures enhanced the sensitivity to NO2 gas. We suggest that the spillover effect of Pd nanoparticles played a significant role in enhancing the response.

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► Coating ZnO-branched nanowires with a Pd shell layer.
► Varying the annealing temperature induced changes in product morphology.
► Morphology of the Pd nanoparticles affected the sensing capability.