Catalytic efficiency of iron oxides in decomposition of H2O2 for simultaneous NOX and SO2 removal: Effect of calcination temperature

Iron oxide catalysts were used for the study of catalytic decomposition of H2O2 into center dot OH radicals for simultaneous oxidation-removal of NOX and SO2. These catalysts were prepared by Fe(NO3)(3)center dot 9H(2)O calcined at different temperatures. The objects were to determine the catalytic efficiency toward the oxidation-removal of SO2 and NOX in relation to the calcination temperature. 100% SO2 removal is achieved in all conditions, but NOX removal increases with the calcination temperature rising. SEM and TEM analyses indicated that the pellet-type particles containing hematite were firstly formed on the surface of large aggregates, and then peeled off from the surface layer by layer as the calciantion temperature increased from 100 to 300 degrees C. This separating process led to the increase of specific surface areas and the transformation from iron composition to hematite, thus benefiting the catalytic removal efficiency. At higher temperatures (>300 degrees C), the iron nitrate was gradually melted, dramatically reducing the specific surface areas. However, higher calcination temperature benefits the generation of oxygen vacancies, which had a more apparent promotional effect on the catalytic efficiency. And finally, the promotional mechanism of oxygen vacancies is deduced in this paper. (C) 2014 Elsevier B.V. All rights reserved.