Bi-Induced Asymmetric Oxo-Bridge on PdNi Metallene for Enhanced Ethanol Oxidation Reaction

The rational design of interfacial active sites is crucial for enhancing the activity and durability of Pd-based electrocatalysts for ethanol oxidation reaction (EOR). Herein, an ultrathin PdNi metallene (PdNiene) with unique asymmetric Pd─O─Bi oxo-bridge sites (PdNi-O-Biene) is synthesized via a multi-step hydrothermal method. The ultrathin 2D nanosheet structure of the metallene enables abundant exposure of Pd active sites. Notably, Ni incorporation facilitates OH * adsorption/formation and thereby promotes the oxidative removal of CO * intermediates, while the Bi-induced asymmetric oxo-bridge interface triggers interfacial charge redistribution around Pd active centers, which further facilitates CO * desorption/oxidative removal and efficient C─C bond cleavage, thus favoring the C1 reaction pathway. As a result, the optimized PdNi-O-Biene demonstrates exceptional mass activity (8.42 A mg Pd −1 ) and specific activity (28.09 mA cm ECSA −2 ) for EOR in alkaline electrolyte, representing improvements of 5.5 and 3.7 times over commercial Pd nanoparticles (Pd NPs), respectively. This work not only provides an effective strategy for the synthesis of high-performance EOR electrocatalysts but also highlights the potential of atomic-scale interface engineering for alcohol oxidation reactions.