Nanofibers of Palladium (Pd)-sensitized SnO2 Encapsulated with Polyaniline for Effective Hydrogen Gas Sensing

Abstract

In this paper, we have successfully synthesized Pd-doped SnO₂ nanofibers
encapsulated with Polyaniline (PANI). The morphology of nanofibers was investigated
using Scanning Electron Microscopy (SEM) technology. SEM study suggested that the
diameter of Pd-doped SnO₂ encapsulated with polyaniline (PSP) nanofibers was found in
the range 200-400 nm. The average diameter of PSP nanofibers was estimated using
ImageJ software. XRD study of pure FIBRESnO2 and PSP nanofibers shows perfect
matching of major peaks corresponding to Tin Oxide (SnO₂). EDAX pattern depicted
weight percentage of constituent elements indicated the presence of Palladium (Pd) in
nanofibers. The study revealed that PSP nanofibers were more sensitive as compared to
pristine SnO₂ nanofibers. The working temperature of PSP nanofibers was found 32°C. The
low working temperature provokes the use of PSP nanofibers as a promising hydrogen gas
sensor. Response and recovery time of 34 seconds and 63 seconds respectively has been
observed for PSP nanofibers. Palladium (Pd) could have played a major role in higher
response towards hydrogen gas sensing. The mesoporous PSP electrospun nanofibers
exhibited excellent response and recovery behavior, with much higher sensitivity to H2 as
compared with pure SnO₂ nanofibers. It could be understood that the high gas sensing
performance of PSP nanofibers is obtained from the high surface area, with more activity at
Pd active sites of nanofibers. Highly porous nature of electrospun nanofibers led to
effective surface interaction between the hydrogen gas molecules and SnO₂ active site
mediated by palladium for electron transfer through the matrix of nanofibers.

Keywords: Nanofibers, Hydrogen sensing, Pd-doped SnO₂ Polyaniline (PSP),
Electrospinning, Polyaniline.