Nanocasted synthesis of mesoporous LaCoO3 perovskite with extremely high surface area and excellent activity in methane combustion

Ordered mesoporous LaCoO3 perovskite with high surface area was synthesized via nanocasting strategy by using ordered mesoporous cubic (Ia3d) vinyl silica as the template. The sample, prepared by filling mesopores in silica template with a La-Co citrate complex precursor followed by calcination and silica removal, was characterized by XRD, TEM, and nitrogen sorption techniques, and its catalytic activity was tested for complete methane oxidation. The wide-angle XRD pattern showed LaCoO3 perovskite was formed and no La-oxide/Co-oxide phases were detected in the obtained material. This LaCoO3 perovskite displayed a high BET surface area of 96.7 m(2) g(-1) from nitrogen sorption analysis and a three-dimensional ordered mesostructure from TEM images, as well as a small-angle XRD pattern. Moreover, this material showed much higher activity in the complete methane oxidation than the conventional bulk LaCoO3 perovskite. The light-off temperature (T-10) and the half-conversion temperature (T-50) were at 335 and 470 degrees C, respectively. Further analysis by means of H-2-TPR and XPS techniques showed that the existence of high valent cobalt ions and high content of O-2(2-)/O- species contributed to the high activity.