Reactivity of the Gold/Water Interface During Selective Oxidation Catalysis

• Published in: Science (American Association for the Advancement of Science) Vol. 330; no. 6000; pp. 74 - 78
• Main Authors: Zope, Bhushan N, Hibbitts, David D, Neurock, Matthew, Davis, Robert J
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.10.2010; The American Association for the Advancement of Science
• Subjects: Alcohols; Aqueous chemistry; Atoms; Catalysis; Catalysts; Catalytic oxidation; Chemical bases; Chemical reactions; Density functional theory; Ethanol; Ethyl alcohol; Gold; Hydroxides; Liquids; Oxidation; Peroxides
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1195055

The selective oxidation of alcohols in aqueous phase over supported metal catalysts is facilitated by high-pH conditions. We have studied the mechanism of ethanol and glycerol oxidation to acids over various supported gold and platinum catalysts. Labeling experiments with ¹⁸O₂ and H₂¹⁸O demonstrate that oxygen atoms originating from hydroxide ions instead of molecular oxygen are incorporated into the alcohol during the oxidation reaction. Density functional theory calculations suggest that the reaction path involves both solution-mediated and metal-catalyzed elementary steps. Molecular oxygen is proposed to participate in the catalytic cycle not by dissociation to atomic oxygen but by regenerating hydroxide ions formed via the catalytic decomposition of a peroxide intermediate.