Nanocomposites SnO2/Fe2O3: Sensor and catalytic properties

Nanocomposites SnO2/Fe2O3 have been obtained in whole concentration range (0-100mol% Fe2O3) using wet chemical synthesis. The gas sensor properties of nanocomposites towards CO (40-150ppm), ethanol (10-200ppm), H2S (2-10ppm) and NO2 (50ppb-10ppm) have been studied by conductance measurements in temperature range 150-450 degrees C. Balancing the SnO2/Fe2O3 molar ratio sensors performances, can be tailored to obtain materials suitable for different applications. High responses towards ethanol together with low humidity effects have been observed for samples with a high Fe2O3 content (x > 70mol%). Acidic and redox properties of the samples were characterized by NH3-TPD and H-2-TPR, respectively. Catalytic properties of nanocomposites were studied in ethanol oxidation using continuous-flow catalytic system. It is demonstrated that increase of Fe2O3 content reduces the amount of surface acid sites and enhances the oxidizing capability of nanocomposites in ethanol oxidation. (c) 2006 Elsevier B.V. All rights reserved.