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. Pt0 has a 7‐fold higher activity for dehydrogenation reactions than for oxidation reactions, while PtOx is equally active for both reactions. Thus, Pt0 promotes glucose dialdehyde formation, while PtOx favors gluconate formation. The successive dehydrogenation of gluconate is achieved selectively at the primary alcohol group by Pt0, while PtOx also promotes the dehydrogenation of secondary alcohol groups, resulting in more complex reaction mixtures. The role of Pt oxidation state on the activity and selectivity was elucidated for the electrocatalytic oxidation of glucose. A new analytical approach was used to quantify all (intermediate) products. Pt0 was found to promote the dehydrogenation of primary alcohol groups (i.e., promote glucose dialdehyde formation), while PtOx was found to promote oxygen transfer reactions (i.e., promote gluconic acid formation).