Abstract:

SnO₂ nanofibers fabricated by electrospinning were coated with PdO, Au, and CdO. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) tests were used to characterize the nanofibers. The diameters of bare and coated SnO₂ nanofibers were approximately 200 nm, and had 15-nm diameter grains. The gas-sensing properties of all the nanofibers were characterized under static gas conditions. The results indicated that the bare SnO₂ nanofibers were sensitive to formaldehyde; however the sensitivity of the coated nanofibers was better. In particular, the CdO-coated SnO₂ exhibited the highest sensitivity to formaldehyde, the shortest response and recovery times, and good selectivity. The operating temperature of the Au-coated SnO₂ decreased from 300 to 200 ℃, while the PdO-coated SnO₂ exhibited the highest sensitivity to toluene. The sensing mechanism of the coated SnO₂ nanofibers was investigated.

Key words: Gas sensor, SnO₂, Coating, Electrospinning, Gas sensing mechanism