Catalytic decomposition of phenethyl phenyl ether to aromatics over Pd–Fe bimetallic catalysts supported on ordered mesoporous carbon

Abstract

A series of bimetallic Pd–Fe catalysts supported on ordered mesoporous carbon (denoted as Pd1–FeX/OMC) were prepared with a variation Fe/Pd molar ratio (X), and they were applied to the catalytic decomposition of phenethyl phenyl ether to aromatics. Phenethyl phenyl ether was used as a lignin model compound for representing β-O-4 linkage in lignin. The effect of Fe/Pd molar ratio on the catalytic activities and physicochemical properties of bimetallic Pd1–FeX/OMC catalysts was investigated. It was found that crystalline phase, reducibility, chemical state, and electronic property of Pd1–FeX/OMC catalysts were strongly influenced by Fe/Pd molar ratio. In particular, modified electronic property derived from the interaction between Pd and Fe significantly changed the hydrogen adsorption ability and bimetallic structure of the catalysts. Conversion of phenethyl phenyl ether continuously decreased with increasing Fe/Pd molar ratio, whereas selectivity for aromatics increased and then became almost constant with increasing Fe/Pd molar ratio. As a consequence, yield for aromatics showed a volcano-shaped trend with respect to Fe/Pd molar ratio. Catalytic performance of Pd1–FeX/OMC catalysts was closely related to the hydrogen adsorption ability and bimetallic structure of the catalysts. Among the catalysts tested, Pd1–Fe0.7/OMC catalyst with moderate hydrogen adsorption ability and with bimetallic structure of Pd1Fe0.7 composition showed the highest yield for aromatics. Thus, an optimal Fe/Pd molar ratio was required to achieve maximum production of aromatics through selective cleavage of CO bond in phenethyl phenyl ether over Pd1–FeX/OMC catalysts.