Balancing in-plane pores and interlayer channels of porous MXene nanosheet membranes for scalable hydrogen purification

Two-dimensional (2D) nanosheet membranes exhibit promising H2 purification due to their atomic thickness. However, the synergistic interplay between in-plane pores and interlayer spacing on gas transport in 2D membrane has never been studied. Here, we engineer porous MXene nanosheets with artificially controllable in-plane pore to construct membranes with precise interlayer spacing, balancing the two types of channels for promising H2/CO2 separation. Optimal porous-MXene nanosheet membranes achieve a threefold increase in H2 permeance (1335 GPU) over nonporous-MXene nanosheet membranes (419 GPU) with comparable H2/CO2 selectivity (118). Theory and experiment demonstrate that the larger in-plane pores provide fast mass transfer channels enhancing H2 permeance, while smaller interlayer spacings as effective sieving channels govern selectivity. The Raman mapping visualizes H2 transport through in-plane pores. Manufacturing of meter-scale membranes underscores industrial viability. This work establishes universal design principles in high-performance 2D nanosheet membranes for separation, adsorption and catalysis. The authors engineer porous MXene nanosheet membranes by balancing in-plane pore and interlayer spacing with dual-channel sieving mechanism, achieving scalable H2/CO2 separation.