Metal-organic framework (MOF) membranes have significant potential for use in efficient gas separation. However, fabricating polymer substrate-supported ultra-thin MOF membranes with no defects remains a challenge. Herein, we proposed an in situ interface self-repair strategy for fabricating ultra-thin and defect-free ZIF-67 membranes for the first time. This was realized by preparing a polyvinyl alcohol (PVA)-Co²⁺ interfacial layer containing a Co²⁺ ion layer and a PVA-Co²⁺ complex layer. The PVA-Co²⁺ interfacial layer released Co²⁺ ions and acted as a metal source to form ZIF-67 membranes by reducing the coordination rate of Co²⁺ ions with 2-methylimidazole. The embedded Co²⁺ ions functioned as anchor sites for the nucleation of ZIF-67 membrane assisted by the interface-enhanced deprotonation of 2-methylimidazole. Especially, the slow release of Co²⁺ ions from the PVA-Co²⁺ interfacial layer facilitated self-repair of defects to form a continuous and dense MOF layer. ZIF-67 membranes, 80-280 nm thick, were successfully synthesized and demonstrated unprecedented CO₂ permeance and good CO₂/N₂ selectivity. This work provides a promising strategy for the fabrication of ultra-thin and defect-free MOF membranes on polymeric support layers for use in practical applications.

金属有机骨架（MOF）膜具有用于有效气体分离的巨大潜力。然而，制造没有缺陷的聚合物支撑的超薄MOF膜仍然是一个挑战。在此，我们首次提出了一种原位界面自修复策略，用于制造超薄且无缺陷的ZIF-67膜。这是通过制备包含Co ²⁺离子层和PVA-Co ²⁺复合层的聚乙烯醇（PVA）-Co ²⁺界面层来实现的。PVA-Co ²⁺界面层释放了Co ²⁺离子，并通过降低Co ²⁺离子与2-甲基咪唑的配位率而充当金属源以形成ZIF-67膜。嵌入式公司²⁺离子在2-甲基咪唑的界面增强去质子作用下辅助ZIF-67膜成核。特别地，Co ²⁺离子从PVA-Co ²⁺界面层的缓慢释放促进了缺陷的自我修复，从而形成了连续且致密的MOF层。成功合成了80-280 nm厚的ZIF-67膜，并显示出前所未有的CO ₂渗透性和良好的CO ₂ / N ₂选择性。这项工作为在实际应用中在聚合物支撑层上制造超薄且无缺陷的MOF膜提供了一种有希望的策略。