Surface-proximate PtCu bimetallic sites for selective Electrocatalytic hydrogenation of benzoic acid.

Cyclohexanecarboxylic acid (CCA), a vital intermediate in chemical and pharmaceutical industries, can be efficiently synthesized via the electrocatalytic hydrogenation of benzoic acid (BA), representing a sustainable synthetic route. However, developing the novel catalyst poses a major challenge due to the currently ambiguous reaction mechanism. In this work, a series of Pt catalysts with Cu as an electronic modifier is explored for selective electrocatalytic hydrogenation of BA to CCA. A surface-proximate PtCu bimetallic site is achieved via an electrochemical-assisted synthesis (EAS) strategy, enabling the fabrication of catalysts to probe different PtCu interactions. The catalytic performance and reaction mechanism are investigated using electrochemical methods, density functional theory (DFT) calculations, and multiple characterization techniques. The results indicate that Cu, as an electron donor, modified the electronic structure of surface Pt atoms, thereby activating BA to CCA and inhibiting benzene ring opening. Near-complete conversion of BA to CCA (∼100%) is achieved by adjusting the electronic density of Pt on the catalyst surface. This strategy provides new insight into the electrocatalytic hydrogenation of reactants to high-value chemicals.