Enhanced NO2 sensing characteristics of Pd-functionalized networked In2O3 nanowires

In this work, we fabricated Pd-functionalized networked In2O3 nanowires. For the Pd-functionalization, In2O3–Pd core–shell nanowires were synthesized by depositing Pd layers using a sputtering method on bare In2O3 nanowires. The continuous Pd shell layers were transformed into islands of cubic Pd/PdO phase by thermal heating. We compared the NO2 sensing characteristics of the sensors fabricated from Pd-functionalized and bare In2O3 nanowires, respectively. The results demonstrated that Pd functionalization greatly improves sensitivity and response time in In2O3 nanowire-based gas sensors. The improvement of sensing properties is likely caused by not only the enhanced adsorption or dissociation of NO2, but also the associated spillover effects, which are both caused by the Pd-functionalization.

► We reported the NO2 gas sensing properties of Pd-functionalized In2O3 nanowires.
► The shell layers were transformed into islands of cubic Pd/PdO phase by heating.
► We discussed the mechanism by which Pd-functionalization enhanced the gas sensing.