Ethanol Sensing Properties of Tin Oxide Doped Using Silver Nanoparticles

Abstract

Composite powders of SnO 2 with different amounts of Ag nanoparticles (0.3 wt%, 0.5 wt%, 0.8 wt% and 1.5 wt%) were prepared by reducing an aqueous silver nitrate solution with NaBH 4 followed by washing and heating treatments. Gas sensors, based on both pure SnO 2 and the prepared composite powders were fabricated by simple, reproducible and low cost method of powder pressing followed by sintering in air at 500oC for 2 hours. The morphology of the materials was characterized by XRD and SEM methods. The gas sensing performance of all sensors were examined in an ethanol vapor atmosphere. Both pure SnO 2 and Ag/ SnO 2 based sensors showed high responses to the ethanol vapor. However, in terms of response time and working temperature the Ag/SnO 2 based sensors showed better performances, i.e. they worked at lower temperatures and responded at shorter times. The response time of all sensors was less than 6s; however, optimized performance was observed for the sensor with 1.5% Ag concentration, showing 99% responses at 260oC with a response time of 3s. The results showed that Ag nanoparticles doped in SnO 2 , effectively can increase sensor performance for ethanol detection.