Study On The Preparation And Gas-sensing Properties Of Multi-level Structure Chromium Oxide

In this paper,by using the chromium acetylacetonate and chromic nitrate as the raw materials,the Cr2O3 nests(spheres)and Cr2O3 nets were prepared by solventhermal method and bio-template method combined with calcination using the methanol(methanol/H2O2)and ethanol as the solvents,respectively.These materials were characterized by TG-DTA,IR,XRD,XPS,SEM and TEM techniques.The results indicated that the Cr2O3 nests consists of 20 nm nanoparticles;the Cr2O3 spheres consists of 50 nm rice-like nanoparticles,about 150-300 nm in diameter;the Cr2O3 nets consists of hollow tubes which were 0.5-1 ?min in diameter and the hollow tube were assembled by 20-50 nm nanoparticles.Thick film-type gas sensors for different morphology materials were fabricated and their gas responses to ethanol,acetone,chlorobenzene,formaldehyde and triethylamine(TEA)were measured.The results indicated that three kinds of hierarchical structure Cr2O3 exhibited high selectivity and sensitivity to TEA.The detection limits of the Cr2o3 nests,Cr2O3 spheres and Cr2O3 nets to TEA were 0.1,1 and 1 ppm,respectively.The sensitivity of Cr2O3 nests to 0.1 and 100 ppm TEA at 217? was 1.2 and 15.6,respectively.The sensitivity of Cr2O3 spheres to 1 and 100 ppm TEA at 217 0Cwas 1.2 and 165.8,respectively.The sensitivity of Cr2O3 nets to 1 and 100 ppm TEA at 170 0C was 1.2 and 1158.8,respectively.