▎ 摘　　要

Metal-organic framework (MOF) membranes are attracting numerous attentions recently. However, fabrication of ultrathin and precisely molecular sieving MOF membranes, especially with highly processable polymeric hollow fiber substrates, is a great challenge. Here, the defect-free ZIF-8 composite hollow fiber membranes with impressive performance for hydrogen permselectivity are fabricated by novel interfacial contra-diffusion synthesis. The reduced graphene oxide (rGO) membranes with good selectivity are prepared on hollow fiber substrates via hydrothermal treatment. By employing the prepared rGO membranes as sharp interfaces to promote the heterogeneous nucleation and control the diffusion of precursors, the ultrathin and uniform MOF membranes with thickness of 150 nm can be regionally crystallized at interfaces by contra-diffusion synthesis. The prepared ZIF-8/rGO composite membranes display outstanding separation performance in H-2 purification, with permeance over 60 x 10(-8) mol m(-2) s(-1) Pa-1 and H-2/CO2, H-2/N-2 and H-2/CH4 selectivities up to 25.3, 70.4, and 90.7, respectively. Moreover, the membranes thus prepared have good reproducibility and long-term stability.