synergism of cobalt and palladium in zeolite MFI for the catalytic NO reduction with methane

摘要

Interest in bimetallic catalyst is motivated by the observation that addition of a second metal to a supported metal catalyst often induces important changes in catalytic and adsorption properties (1-4). Combinations of Co and Pd in zeolities have been studied with high Pd loading, in particular focusing on hydrogenation and hydrogenolysis (2,5-7). Much less is known about the potential for NO reduction of zeolite supported Pd-Co catalysts with low Pd/Co ratio, which appear more attractive not only from an economic point of view. In the present study, such catalysts have been prepared by combining sublimation of the volatile cobalt compound with conventional ion exchange of palladium, XRD, TPR, and EXAFS were used to unravel the chemistry involved during reduction with H_2 and catalytic NO reduction with CH_4 in the presence of excess O_2.