SnO2/Fe2O3 nanocomposites: Ethanol-sensing performance and catalytic activity for oxidation of ethanol

SnO2/Fe2O3 nanocomposites have been prepared over the entire composition range (0-100 mol % Fe2O3) through precipitation from solution, and their ethanol-sensing performance (10-200 ppm C2H5OH) was evaluated using electrical conductivity measurements in the temperature range 150-450 degrees C. The sensing performance of the nanocomposites is shown to strongly depend on their composition. The Fe2O3-rich (> 70 mol % Fe2O3) nanocomposites offer a large C2H5OH response and low sensitivity to ambient humidity. The oxidizing and acid properties of the nanocomposites have been studied using temperature-programmed hydrogen reduction and ammonia desorption measurements, and their catalytic activity for oxidation of ethanol was assessed by gas chromatography mass spectrometry in a flow system. The results indicate that increasing the Fe2O3 content of the nanocomposites reduces the density of acid centers on their surface and enhances their activity for oxidation of ethanol.