Sensor properties of Pd doped SnO2 nanofiber enshrouded with functionalized MWCNT

Abstract: In this work, tin oxide (SnO2)/multi-walled carbon nanotube (MWCNT) composite based ethanol sensor that exhibits fast response/recovery behaviour, large sensitivity, and good selectivity was demonstrated. First, Pd doped SnO2 (SnO2-Pd) nanofibers was prepared on the interdigitated electrodes (IDE) using electrospinning technique, followed by calcination at 600 0C for 2 h. Then, carboxylic acid modified multi-walled carbon nanotube (MWCNT-COOH) was dropped on the nanofibers and allowed to dry at RT. Next, the thin films were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Finally, chemical sensing behaviors of the sensors were analyzed against to ethanol (ETH), toluene (TOL), trichloroethylene (TCE), acetone (ACE) and binary mixing with water. It was demonstrated that increasing the temperature and gas concentration has led to increased sensor response for SnO2-Pd nanofiber system. However, there was no general rule found for MWCNT-COOH coated SnO2-Pd nanofiber system. A novel sensing mechanism was offered for the composite structure.