Cr2O3nanoparticle-anchored SnO2nanowires are synthesized to fabricate highly sensitive and selective ethanol gas sensor. SnO2nanowires are synthesized by vapor-liquid-solid method as a gas detection material, and Cr2O3nanoparticles are anchored to SnO2nanowires to improve sensing properties. Anchoring Cr2O3nanoparticles are synthesized to deep the SnO2nanowire sample to chromium oxide colloid gel, and anneal this sample at 500°C, in a vacuum atmosphere. This hybrid structured sensor presents 4 times improved ethanol sensing response compared with as-synthesized SnO2nanowires when exposed to 100ppm ethanol gas in 300°C. Furthermore, sensing selectivity of ethanol versus other volatile organic compound (VOC) gas is also drastically improved. Generally, nanostructured SnO2is known as very sensitive material to chemical gas, but it is hard to apply to commercial gas sensor since its extremely low selectivity. However, using this hybrid structured sensor, highly sensitive and selective ethanol sensor can be fabricated. This improvement of ethanol sensing properties can be explained that variation of energy bandgap of homojunction between n-SnO2and n-SnO2and heterojunction between n-SnO2and p-Cr2O3of nanowires. Furthermore, catalytic properties of this hybrid structure nanowire make selectivity of sensor improved.
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