Activation by hydrothermal treatment of low surface area ABO3-type perovskite oxide catalysts

Surface area and methane conversion activity in a complete combustion of methane of LaCoO3 and LaMnO3 perovskite-type oxides are increased very markedly by treating the perovskite-type oxides with water under autogeneous pressure (at 125–300°C) and/or with steam (at 350–800°C) at atmospheric pressure for 4 h. The methane combustion activity per unit surface is, however, decreased markedly due to the hydrothermal water treatment of LaCoO3, but it is influenced only to a small extent because of the steam treatment of LaCoO3 and the hydrothermal water treatment of LaMnO3.