Synthesis and Selective Sensing Properties of rGO/Metal-Coloaded SnO₂ Nanofibers

Abstract

Ternary nanocomposites containing reduced graphene oxide (rGO) and metal (Pt or Pd)-coloaded SnO₂ nanofibers (NFs) have been successfully synthesized by an electrospinning method. Transmission electron microscopy and field-emission scanning electron microscopy analyses revealed the NF morphology of the synthesized products. The gas sensing properties of the synthesized materials towards 1 ppm and 5 ppm C₆H₆, C₇H₈, and CO were tested, demonstrating enhanced sensing capability of the rGO/metal (Pt or Pd)-coloaded SnO₂ NF sensor compared with that of pristine or rGO-loaded SnO₂ NF sensors. Furthermore, selective sensing towards either C₆H₆ or C₇H₈ can be achieved by using Pd or Pt loading, respectively. The high specific surface area due to the existence of nanograins and p-rGO/n-SnO₂ heterojunctions in the NFs, nanoheterojunctions between the noble metals and SnO₂, as well as a sensitizing effect of Pt and Pd were responsible for the enhanced sensing response of the rGO/metal-coloaded SnO₂ NF sensors. The obtained results demonstrate the promotional effect of coloading, as well as selectivity tuning by proper choice of a noble metal, being extendable to other gas sensing materials.