Structural disproportionation of Ag20Cu10 highlights the impact of cluster structure on electrocatalytic properties for CO2 reduction

Abstract

Understanding the relationship between cluster structure and catalytic performance is fundamental for developing advanced cluster-based catalysts. The interactions between SbF₆⁻ ions and metal nanoclusters prove particularly significant in modulating cluster structures and properties. Herein, we report the synthesis of a novel Ag₂₀Cu₁₀(Dppm)₂(SAdm)₁₄Cl₈ (Ag₂₀Cu₁₀ for short) nanocluster featuring an Ag₁₇ barrel-like core surrounded by an Ag₃Cu₁₀(Dppm)₂(SR)₁₄Cl₈ shell. Upon introduction of NaSbF₆, Ag₂₀Cu₁₀ undergoes structural disproportionation transformation to form superatomic alloy clusters [Ag₈Cu₁₂(Dppm)₄(SAdm)₈Cl₈]²⁺ (2e and Ag₈Cu₁₂ for short) and [Ag₁₇Cu₁₅(SAdm)₁₃(Dppm)₃Cl₉]²⁺ (8e and Ag₁₇Cu₁₅ for short). These three structures share similar staples and Ag-bridging atoms, indicating core recombination while maintaining peripheral motifs during transformation. Electronic structure analysis through density functional theory (DFT) calculations reveals distinct characteristics of these Ag–Cu nanoclusters. Evaluation of their CO₂ reduction reaction (CO₂RR) capabilities demonstrates superior catalytic performance of Ag₂₀Cu₁₀ compared to Ag₈Cu₁₂ and Ag₁₇Cu₁₅. This enhanced performance highlights the unique structural and electronic properties of Ag₂₀Cu₁₀, which enable more effective catalytic activity during the CO₂RR process. These findings emphasize the pivotal role of SbF₆⁻ in modulating Ag–Cu nanocluster structures and highlight the impact of structural features on electrocatalytic performance.