Oxidation of benzyl alcohol over nanoporous Au–CeO2 catalysts prepared from amorphous alloys and effect of alloying Au with amorphous alloys

Au–CeO2 catalysts are prepared from amorphous Ce–Al alloys by the dealloying method, and their catalytic performances are examined in the oxidation of benzyl alcohol to benzaldehyde using O2 as an oxidant. The catalytic activity of the Au–CeO2 catalysts is improved using an amorphous alloy as a precursor, and further improved activity is attained by directly alloying Au with Ce–Al rather than by depositing Au on preformed CeO2. Consequently, Au–CeO2 prepared directly from an amorphous Au–Ce–Al alloy exhibits the highest activity among the prepared samples, despite its low surface area. Detailed characterization by means of XPS analysis indicates that most of the Au species in Au–CeO2 prepared from the amorphous Au–Ce–Al alloy exist in a +1 oxidation state (Au+). The presence of Au+ facilitates the migration of oxygen atoms through the lattice, which likely contributes to the high catalytic activity of the Au–CeO2 catalyst.