Steering the Selectivity of Electrocatalytic Glucose Oxidation by the Pt Oxidation State.

Electrocatalytic glucose oxidation can produce high value chemicals, but selectivity needs to be improved. Here we elucidate the role of the Pt oxidation state on the activity and selectivity of electrocatalytic oxidation of glucose with a new analytical approach, using high-pressure liquid chromatography and high-pressure anion exchange chromatography. It was found that the type of oxidation, i.e. dehydrogenation of primary and secondary alcohol groups or oxygen transfer to aldehyde groups, strongly depends on the Pt oxidation state. Pt has a 7-fold higher activity for dehydrogenation reactions than for oxidation reactions, while PtO is equally active for both reactions. Thus, Pt promotes glucose dialdehyde formation, while PtO favors gluconate formation. The successive dehydrogenation of gluconate is achieved selectively at the primary alcohol group by Pt , while PtO also promotes the dehydrogenation of secondary alcohol groups, resulting in more complex reaction mixtures.