Abstract: La0.8Sr0.2FeMn1.5Al9.5O19-δ (LSFMAO) hexaaluminate aerosol was prepared by co-precipitation combined with supercritical drying and high temperature calcinations. XRD, SEM, BET, TPR characterizations as well as methane catalytic combustion were performed to investigate the effects of supercritical drying and high temperature calcinations on the structure and reactivity of the catalysts. The results indicated that the plate-like LSFMAO hexaaluminate aerosol was formed after calcination of the aerosol precursors at 1200 ℃. The as-prepared LSFMAO hexaaluminate possesses large specific surface area (16 m2·g-1) and excellent catalytic combustion activity at high gas space velocity. However, further calcinations of the LSFMAO hexaaluminate at 1300 ℃ and 1400 ℃ resulted in severe sintering and reduction of catalytic activity. These results revealed that supercritical drying was helpful to promote the combustion activity and resist sintering of the LSFMAO hexaaluminate up to 1200 ℃ above which the sintering resistance and redox performance of LSFMAO hexaaluminates were mainly determined by the components and intrinsic properties.

Key words: Supercritical drying, Hexaaluminate, Aerosol, Catalytic combustion of methane