PMMA-templating preparation and catalytic activities of three-dimensional macroporous strontium ferrites with high surface areas for toluene combustion

Three-dimensional (3D) macroporous perovskite-type oxides SrFeO3−δ (i.e., SFO-xEG, x = 1, 3, and 6) with a cubic perovskite structure have been prepared using the citric acid-assisted poly(methyl methacrylate)-templating method in the presence of a certain amount (1, 3 or 6 mL) of ethylene glycol (EG). The physicochemical properties of the materials were characterized by means of numerous techniques and their catalytic activities were evaluated for toluene combustion. It is shown that the SFO-3EG sample possessed the best pore quality and highest surface area (ca. 34 m2/g). Most of the pores of SFO-xEG (x = 1, 3, and 6) were ca. 72, 52, and 64 nm, respectively. There was a good relationship of surface area, oxygen adspecies concentration, and low-temperature reducibility with catalytic performance of the sample (i.e., SFO-3EG > SFO-6EG > SFO-1EG > SFO-bulk). The SFO-3EG catalyst performed the best, giving a T50% of ca. 270 °C and a T90% of ca. 310 °C at space velocity = 5000 mL/(g h). It is concluded that the good catalytic performance of SFO-3EG was associated with its large surface area, high oxygen adspecies concentration, and good low-temperature reducibility as well as the high-quality 3D macroporous structure.

Using the citric acid-assisted PMMA-templating method, we prepared 3D macroporous SrFeO3−δ (SFO-xEG; x = 1, 3, 6) with high surface areas. It is found that the good catalytic performance of the SFO-3EG sample for toluene combustion was associated with its large surface area, high oxygen adspecies concentration, and good low-temperature reducibility as well as the high-quality 3D macroporous structure.Figure optionsDownload high-quality image (406 K)Download as PowerPoint slideHighlights
► High-surface-area 3D macroporous SrFeO3−δ are prepared by the PMMA-templating method.
► Ethylene glycol is needed for generation of high-quality 3D macroporous SrFeO3−δ.
► SFO-3EG is high in surface area and Oads concentration and good in reducibility.
► 3D macroporous SrFeO3−δ catalysts perform well in the combustion of toluene.
► Surface area, Oads concentration, and reducibility determine the catalytic activity.