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Indexed by:期刊论文

Date of Publication:2015-01-01

Journal:RSC ADVANCES

Included Journals:SCIE、EI、Scopus

Volume:5

Issue:64

Page Number:51953-51960

ISSN No.:2046-2069

Abstract:A low power consumption ethanol gas sensor based on a suspended micro-hotplate was fabricated using the droplet guiding deposition technique. FESEM and XRD characteristics show that the host material, SnO2, maintained the rutile structure and a particle size of similar to 40 nm. HRSEM and TEM images illustrate the porous and permeable morphologies of SnO2/TiO2 and SnO2/CNT. The optimal sintering and operating temperatures for detecting ethanol are 450 degrees C and 300 degrees C respectively. The response was defined as the ratio of sensor resistance measured in air and ethanol (R-a/R-g), and it was improved by adding 2 wt% TiO2 and 1 wt% CNT. The responses of SnO2/TiO2, SnO2/CNT, and pure SnO2 to the lowest concentration of 1 ppm are about 5.2, 4.8 and 2.2 respectively. With an increase in the concentration to 500 ppm ethanol, the responses increase rapidly and reach about 21.5, 19.4 and 15.2. In the low range from 1 ppm to 50 ppm, the variation curves of response are basically linear. The dynamic responses indicate fast response/recovery speed, relatively steady baseline and good repeatability. The experimental results show that the MHP-based sensors made of SnO2/TiO2 or SnO2/CNT have good sensitivity and selectivity for detecting ethanol in a wide range from 1 ppm to 500 ppm while consuming only 12 mW of power.