Study of Lanthanum Manganate and Yttrium-Stabilized Zirconia-Supported Palladium Dual-Bed Catalyst System for the Total Oxidation of Methane: A Study by O-18(2)/O-16(2) Isotopic Exchange

摘要

A significant enhancement of the yttrium-stabilized zirconia-supported palladium (0.2 wt% Pd/YSZ) catalytic activity for the total oxidation of methane was achieved in a dual-bed system by the association of LaMnO3+Pd/YSZ materials. The combination with the best performance was 40 wt% LaMnO3+60 wt% Pd/YSZ. Pd/YSZ and LaMnO3 perovskite were characterized by using the O-18(2) exchange technique. A Mars-van Krevelen mechanism was demonstrated over Pd/YSZ at 425 degrees C. Additionally, it was evidenced that LaMnO3 activated the O-2 molecule on the YSZ oxygen vacancy sites to result in a significant increase of the oxidation rate characterized by a correlating decrease of the light-off temperature of 65 degrees C.