Pd-Dispersed CeO₂ Catalyst Prepared from Dealloying the Pd–Ce–Al Ternary Amorphous Alloy Used for Oxidation Reaction

Abstract

The relationship between preparation method and the catalytic activity as well as reusability for PdCeO 2 catalyst was investigated. Pddispersed CeO 2 prepared from dealloying in NaOH aqueous solution of a PdCeAl ternary amorphous alloy as a precursor. The dealloying proceeded by active dissolution of Al and Ce to form sodium aluminate ion, Na[Al(OH 4)](aq), and CeO 2 particles, respectively. At the same time, Pd acting as cathode resulted in directly to be metallic nailed-particles exposing partly from the matrices of the CeO 2 particles. Its catalytic activity and reusability as a function of its surface area of exposed-Pd as well as sample surface area were investigated, compared with those of Pd-supported CeO 2 which was prepared by conventional liquid phase reduction. Pd-dispersed CeO 2 was higher in exposed Pd surface area than Pd-supported CeO 2 despite its lower sample surface area. It is likely that the nailed Pd on the CeO 2 prevents themselves from aggregation during sample preparation and reusability study. As a result, in the oxidation reaction of methyl benzyl alcohol, Pd-dispersed CeO 2 showed higher catalytic activity and reusability than Pd-supported CeO 2. The oxidation reaction of methyl benzyl alcohol is a measure of the oxidative decomposition reaction of harmful substances. Pd-dispersed CeO 2 is expected to be widely used for the oxidative decomposition reaction of harmful substances.