Improvement of Gas Sensing Characteristics by Adding Pt Nanoparticles on ZnO-Branched SnO2 Nanowires.

We coated zinc-oxide (ZnO)-branched tin oxide (SnO2) nanowires with a Pt shell layer via a sputtering method and subsequently annealed the composite to generate Pt nanoparticles. The spillover effect of Pt nanoparticles was expected to play a significant role in enhancing the response. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that the nanoparticles were comprised of a cubic Pt phase. A sensing test with NO2 gas revealed that the sensor response to NO2 gas was significantly increased, being related to the spillover effect of the Pt nanoparticles. As a result of the Pt-functionalization, the sensor response time and recovery time were decreased and increased, respectively. The high sensor response and fast response time make Pt-functionalized ZnO branched nanowires a promising candidate for gas sensors. The present work will be useful in exploring new areas of multiple-component nanosystems.