Electrochemically tunable proton coupled electron transfer in Pd–catalyzed benzaldehyde hydrogenation

Acid–functionalization of carbon support allows enhancing the electrocatalytic activity of Pd to hydrogenate benzaldehyde to benzyl alcohol in proportion to the concentration of Brønsted acid sites. In contrast, the hydrogenation rate is not affected when H 2 is used as reduction equivalent. The different response to catalyst properties is shown to be caused by differences in the hydrogenation mechanism between the electrochemical and the H 2 induced hydrogenation pathways. Here, the enhancement of the electrocatalytic reduction is realized by the participation of support generated hydronium ions at the perimeter of metal particles.