Efficient Reduction of CO ₂ via Modified Bimetallic Metal–Organic Frameworks‐Based Cycloaddition under Mild Conditions

The incorporation of functionalized secondary metal nodes into bimetallic metal–organic frameworks (MOFs) enhances their performance and application potential. This study investigates Cu/Zn‐MOF‐74 catalysts with varying metal ratios for carbon dioxide (CO₂)‐epoxide cycloaddition. Compared to monometallic Cu‐MOF‐74 and Zn‐MOF‐74, the bimetallic system shows superior catalytic activity for epoxides conversion. Vim─COOH@Cu/Zn‐MOF‐74 is developed by introducing hydrogen bond donors (HBD) and nitrogen‐containing linkers. The optimal Vim─COOH@Cu₀.₆₇Zn₀.₃₃‐MOF‐74 demonstrates outstanding performance in CO₂‐epichlorohydrin cycloaddition, achieving 96.4% conversion and 98.5% selectivity under mild conditions (80 °C, 1.0 MPa, 24 h) without co‐catalysts, while maintaining excellent recyclability. Using a one‐pot synthesis, bimetallic MOFs with controlled Cu/Zn ratios are prepared. The framework is further modified by incorporating 1,4‐butanediyl‐3,3′‐bis‐1‐vinylimidazolium bromide and HBD‐functionalized imidazole bromide monomers. The resulting composites achieve over 80% conversion under solvent‐free, co‐catalyst‐free conditions due to synergistic effects between Lewis acid sites, carboxyl groups, and nucleophilic Br⁻ ions. This work presents an effective strategy for developing efficient MOF catalysts for CO₂ conversion. The Vim─COOH@Cu/Zn‐MOF‐74 system demonstrates significant potential for sustainable CO₂ utilization in cyclic carbonate synthesis, combining high activity, selectivity, and stability under environmentally friendly reaction conditions.