Pd-loaded In2O3 nanowire-like network synthesized using carbon nanotube templates for enhancing NO2 sensing performance

Abstract

Pd-loaded In₂O₃ nanowire (NW)-like networks were synthesized via electroless plating using carbon nanotubes (CNTs) as templates, followed by oxidation and removal of the CNTs at 550 °C. Palladium (Pd) was introduced to activate the surface of the CNTs for subsequent plating. Before calcination, Pd was loaded onto In₂O₃. The as-synthesized Pd-loaded In₂O₃ replicated the structure of the CNTs, forming a porous NW-like network with a very large specific surface area. Furthermore, the NO₂ gas sensing properties of the Pd-loaded In₂O₃ NW-like network, porous Pd–In₂O₃ and porous unloaded-In₂O₃ were investigated. The results demonstrated that the Pd–In₂O₃ NW-like network exhibits superior sensitivity with short response and recovery times, and demonstrates a significant response when exposed to NO₂ at concentrations as low as 5 ppm at a temperature of 110 °C. A synergy of electric and chemical effects has been proposed to explain the gas sensing enhancement.