Study on Formaldehyde Gas Sensor Based on SnO{sub}2 with La{sub}2O{sub}3-ZnO Doping

摘要

SnO{sub}2 nanpowder was prepared by sol-gel method. The SnO{sub}2 based formaldehyde sensor with the doping of La{sub}2O{sub}3 (5wt%)-ZnO(3wt%) was fabricated. The range of the detecting concentration for formaldehyde is from 10 μg/g to 300 μg/g at 140°C. The sensitivity (S=R{sub}0/R{sub}g) to 10 μg/g formaldehyde is 2 and to 300 μg/g formaldehyde is 16. The 0.4 nm molecule-sifter layer was coated on the surface of SnO{sub}2 material, the result shows that the selectivity of the formaldehyde sensor is improved. The La{sub}2O{sub}3-ZnO doped SnO{sub}2 sensor shows better stability during 60 days testing.