Zirconia supported LaMnO3 monoliths for the catalytic combustion of methane

Novel LaMnO3 perovskite-based structured catalysts have been studied for methane catalytic combustion under lean, pre-mixed conditions. Monoliths have been prepared by wash-coating cordierite honeycomb substrates with lanthanum stabilised ZrO2, on which the perovskite was dispersed by either impregnation or deposition–precipitation (DP) routes. Extensive physico-chemical characterisation of monoliths (by means of XRD, BET, SEM-EDAX, TPR of H2 and drift analysis) has revealed the presence of a zirconia layer firmly anchored on cordierite walls, with remarkable surface area and chemical inertia towards negative interactions with perovskitic active phase. The activity of fresh catalysts for methane combustion is significantly enhanced with respect to bulk LaMnO3, due to good dispersion on the porous support. Catalytic performances and durability have been studied under auto-thermal reaction conditions of interest for radiant pre-mixed burners, with maximum catalyst temperatures up to 1000 °C, through accurate characterisation of ignition transients and steady operation, comparing results with those relevant to both nude cordierite and previously developed monoliths of LaMnO3 supported on La stabilised γ-Al2O3.