Copper-Silver Bimetallic Metal-Covalent Organic Frameworks with Unique Intermediate Interlayer Transfer Effects for...

The electrochemical reduction of CO₂ to ethylene (C₂H₄) offers a promising approach to mitigating greenhouse gas emissions while generating high-value chemical products. However, achieving both high C₂H₄ selectivity and long-term catalyst stability remains a significant challenge for single-atom catalysts, primarily due to the absence of adjacent active sites required for the coupling of reaction intermediates. Herein, a bimetallic metal-covalent organic framework (MCOF) with precisely tunable Cu-Ag spatial configurations was developed to enhance CO₂-to-C₂H₄ conversion through a synergistic catalytic mechanism. By optimizing the Cu/Ag molar ratio to 1:1 (Ag_0.5Cu_0.5-CTC-TAPT), the catalyst achieves a Faradaic efficiency for C₂H₄ (FE(C₂H₄)) of 51.5% ± 0.9% at a reduction potential of -1.774 V versus (vs.) RHE, along with a current density of 439.0 ± 7.3 mA cm^-2 and excellent stability (FE(C₂H₄) > 40% over 10 h), outperforming most single-metal M/COFs and MOF-based electrocatalysts that predominantly yield C1 products. In situ spectroscopic analysis and mechanistic studies indicate that Ag sites primarily facilitate CO generation, while neighboring Cu sites promote C─C bond formation. This work introduces a novel design strategy for constructing COF-based materials with adjacent heterogeneous metal active sites, highlighting their significant potential for the electrochemical conversion of CO₂ into valuable C2+ chemicals.