关键词: 金属-有机框架, 低浓度二氧化碳, 电催化二氧化碳还原, 捕集-转化一体化

Efficient capture and electrocatalytic conversion of low-concentration carbon dioxide (15% in flue gas and ~400 ppm in ambient air) represents a promising pathway toward carbon emission mitigation and value-added chemical production. In principle, directly utilizing dilute CO₂ streams could bypass energy-intensive purification steps and improve the overall process economics. However, electrocatalytic CO₂ reduction (eCO₂RR) under low CO₂ partial pressures is fundamentally limited by sluggish CO₂ mass transfer, severe competition from the hydrogen evolution reaction, and performance deterioration induced by impurities (e.g., O₂, NO_x, and SO₂). Moreover, conventional neutral/alkaline electrolytes suffer from pronounced carbonate formation, leading to substantial carbon losses and low single-pass carbon efficiency. These challenges indicate that simply improving intrinsic catalytic activity is insufficient; instead, new materials and system-level strategies are required to simultaneously enrich CO₂, regulate interfacial microenvironments, and decouple separation from conversion. Metal-organic frameworks (MOF), featuring tailorable pore architectures, designable pore chemistry, and the capability of integrating multiple functions into a single material or device component, provide a unique platform to address the above limitations. This Perspective highlights recent advances in MOF-based materials for eCO₂RR using low-concentration CO₂ feedstocks, with an emphasis on representative design paradigms spanning “molecular-scale synergy - reaction-environment regulation - device-level integration”. First, capture and conversion can be coupled within individual MOFs by embedding CO₂-philic motifs and catalytic centers into the same porous scaffold, enabling preferential CO₂ enrichment, and facilitated transport to active sites under simulated flue gas. Second, reaction-environment engineering, particularly under acidic conditions, offers a viable solution to suppress carbonate formation and enhance carbon utilization; protonation of N-rich frameworks can strengthen CO₂ adsorption/transport while limiting proton accessibility to catalytic sites, leading to high Faradaic efficiency and improved single-pass conversion even with dilute CO₂ inputs. Third, device-level strategies further decouple CO₂ purification from downstream electrolysis by integrating MOF-based molecular sieving mixed-matrix membranes (e.g., MOF/PIM-1 composites) into membrane electrode assemblies, allowing in situ enrichment of flue gas- or air-derived CO₂ and impurity removal prior to catalytic conversion. Collectively, these advances demonstrate how MOFs can enable progressive innovations from materials design to interfacial regulation and electrolyzer integration. Finally, key challenges and opportunities are discussed, including mechanistic understanding under complex impurity mixtures, long-term stability, scalable manufacturing of MOF-based layers and membranes, and compatibility with industrial capture and electrolysis infrastructures.

Key words: metal-organic framework, low concentration CO₂, electrocatalytic CO₂ reduction, enrichment-conversion integration