Low-Voltage Electrooxidation of Benzyl Alcohol to Benzoic Acid Enhanced by PtZn-ZnOx Interface

Abstract

The electrocatalytic oxidation of benzyl alcohol to benzoic acid is a process that often requires high voltage, leading to increased energy consumption, side reactions (oxygen evolution reaction (OER)), and catalyst degradation. Herein, our study introduces a novel approach. We demonstrate that a PtZn-ZnO_x catalyst featuring a PtZn intermetallic structure with abundant PtZn-ZnO_x interfaces on the surface allows for the electrocatalytic oxidation of benzyl alcohol to benzoic acid with an impressive selectivity of 99.5% at a low potential of 0.725 V (vs a reversible hydrogen electrode, RHE), which is 0.6 V lower than most reported studies. This high selectivity is a testament to the efficiency of our catalyst, as it significantly reduces the occurrence of side reactions, leading to a more efficient and sustainable process. The experimental and density functional theory calculations demonstrated that the adsorption of Ph–CH₂OH and Ph–CHO and the generation of electrophilic OH* were promoted due to the unsaturated coordination of the Zn atom in the PtZn-ZnO_x interfaces. Furthermore, the potential-determining step of coupling OH* with Ph–CHO was promoted due to the low energy barrier at the PtZn-ZnO_x interface, leading to improved catalytic activity and selectivity. This study outlines a novel approach to designing highly efficient electrocatalysts for high-efficiency alcohol valorization at low voltages.