Metal-organic framework (MOF) membranes have been extensively researched as an innovative membrane material for H₂/CO₂ separation. The preparation of MOF membranes can be extended by constructing MOF membranes with homogeneous heterogeneous structure and the MOF membranes with high permeance and high selectivity can be prepared. Here, we use the chelation-assisted interfacial growth process to construct a seeding layer, and then prepare Co-Zn-ZIF-L membranes with a homogeneous heterogeneous structure by secondary growth for the efficient separation of H₂/CO₂. The resulting Co-Zn-ZIF-L membranes show an H₂ permeance of 2156 GPU and H₂/CO₂ selectivity of 31.6 at 298 K and 1.0 bar, surpassing the Robeson upper bound (2008). Furthermore, the Co-Zn-ZIF-L membrane has a H₂/CO₂ separation stability of 65 h and can efficiently separate to obtain pure H₂.