Microemulsion synthesis of MgO-supported LaMnO 3 for catalytic combustion of methane

Abstract

Catalysts with 20% LaMnO 3 supported on MgO have been prepared via CTAB-1-butanol- iso-octane-nitrate salt microemulsion. The preparation method was successfully varied in order to obtain different degrees of interaction between LaMnO 3 and MgO as shown by TPR and activity tests after calcination at 900 °C. Activity was tested on structured catalysts with 1.5% CH 4 in air as test gas giving a GHSV of 100,000 h −1. The activity was greatly enhanced by supporting LaMnO 3 on MgO compared with the bulk LaMnO 3. After calcination at 1100 °C both the surface area and TPR profiles were similar, indicating that the preparation method is of little importance at this high temperature due to interaction between the phases. Pure LaMnO 3 and MgO were prepared using the same microemulsion method for comparison purposes. Pure MgO showed an impressive thermal stability with a BET surface area exceeding 30 m 2/g after calcination at 1300 °C. The method used to prepare pure LaMnO 3 appeared not to be suitable since the surface area dropped to 1.1 m 2/g already after calcination in 900 °C.