Catalytic removal of toluene over three-dimensionally ordered macroporous Eu1-xSrxFeO3

Three-dimensionally ordered macroporous (3DOM) perovskite-type oxides EuFeO3 (EFO-3DOM) and Eu0.6Sr0.4FeO3 (ESFO-3DOM) were prepared by the citric acid-assisted polymethyl methacrylate-templating method. The physicochemical properties of the materials were characterized by means of numerous techniques. Catalytic activities of these porous samples were evaluated for the combustion of toluene. It is shown that the EFO-3DOM and ESFO-3DOM catalysts were of high-quality 3DOM architecture and single-phase orthorhombic crystal structure with a surface area of 16-31 m(2)/g. The sequence in surface oxygen species concentration and low-temperature reducibility decreased in terms of ESFO-3DOM > EFO-3DOM > EFO-bulk, in good agreement with the order in catalytic activity. The ESFO-3DOM catalyst exhibited the best performance, giving the T-10%, T-50%, and T-90% of 233, 278, and 305 degrees C at a space velocity of 20,000 mL/(g h), respectively. Apparent activation energies of the ESFO-3DOM, EFO-3DOM, and EFO-bulk catalysts were ca. 82, 96, and 104 kJ/mol, respectively. The excellent catalytic activity of ESFO-3DOM might be associated with its higher surface area and surface oxygen species concentration and better low-temperature reducibility as well as high-quality 3DOM structure. (C) 2012 Elsevier B.V. All rights reserved.