Morphological and Compositional Design of Pd–Cu Bimetallic Nanocatalysts with Controllable Product Selectivity toward CO₂ Electroreduction

Electrochemical conversion of carbon dioxide (electrochemical reduction of carbon dioxide) to value-added products is a promising way to solve CO₂ emission problems. This paper describes a facile one-pot approach to synthesize palladium–copper (Pd–Cu) bimetallic catalysts with different structures. Highly efficient performance and tunable product distributions are achieved due to a coordinative function of both enriched low-coordinated sites and composition effects. The concave rhombic dodecahedral Cu₃Pd (CRD-Cu₃Pd) decreases the onset potential for methane (CH₄) by 200 mV and shows a sevenfold CH₄ current density at −1.2 V (vs reversible hydrogen electrode) compared to Cu foil. The flower-like Pd₃Cu (FL-Pd₃Cu) exhibits high faradaic efficiency toward CO in a wide potential range from −0.7 to −1.3 V, and reaches a fourfold CO current density at −1.3 V compared to commercial Pd black. Tafel plots and density functional theory calculations suggest that both the introduction of high-index facets and alloying contribute to the enhanced CH₄ current of CRD-Cu₃Pd, while the alloy effect is responsible for high CO selectivity of FL-Pd₃Cu.