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

Abstract

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 Cu₃ Pd (CRD-Cu₃ Pd) 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 Pd₃ Cu (FL-Pd₃ Cu) 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-Cu₃ Pd, while the alloy effect is responsible for high CO selectivity of FL-Pd₃ Cu.