Ethanol Sensing Properties of Tin Oxide Doped Using Silver Nanoparticles

Abstract

Composite powders of SnO2 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 NaBH4 followed by washing and heating treatments. Gas sensors, based on both pure SnO2 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 SnO2 and Ag/ SnO2 based sensors showed high responses to the ethanol vapor. However, in terms of response time and working temperature the Ag/SnO2 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 SnO2, effectively can increase sensor performance for ethanol detection.