6 November 2019

Enhancement mechanisms of ethanol-sensing properties based on Cr2O3 nanoparticle-anchored

SnO2 nanowires

Cr2O3nanoparticle-anchored SnO2nanowires are synthesized to fabricate highly sensitiveand selective ethanol gas sensor. SnO2nanowires are synthesized by vapor-liquid-solidmethod as a gas detection material, and Cr2O3nanoparticles are anchored to SnO2nanowires to improve sensing properties. Anchoring Cr2O3nanoparticles are synthesizedto deep the SnO2nanowire sample to chromium oxide colloid gel, and anneal this sample at500◦C, in a vacuum atmosphere. This hybrid structured sensor presents 4 times improvedethanol sensing response compared with as-synthesized SnO2nanowires when exposedto 100 ppm ethanol gas in 300◦C. Furthermore, sensing selectivity of ethanol versus othervolatile organic compound (VOC) gas is also drastically improved. Generally, nanostructuredSnO2is known as very sensitive material to chemical gas, but it is hard to apply to commer-cial gas sensor since its extremely low selectivity. However, using this hybrid structuredsensor, highly sensitive and selective ethanol sensor can be fabricated. This improvementof ethanol sensing properties can be explained that variation of energy bandgap of homo-junction between n-SnO2and n-SnO2and heterojunction between n-SnO2and p-Cr2O3ofnanowires. Furthermore, catalytic properties of this hybrid structure nanowire make selec-tivity of sensor improved.