Unexpected Self‐Assembly of Nanographene Oxide Membranes upon Electron Beam Irradiation for Ultrafast Ion Sieving

Nanographene oxide (nGO) flakes-graphene oxide with a lateral size of ≈100 nm or less-hold great promise for superior flux and energy-efficient nanofiltration membranes for desalination and precise ionic sieving owing to their unique high-density water channels with less tortuousness. However, their potential usage is currently limited by several challenges, including the tricky self-assembly of nano-sized flakes on substrates with micron-sized pores, severe swelling in aqueous solutions, and mechanical instability. Herein, the successful fabrication of a robust membrane stacked with nGO flakes on a substrate with a pore size of 0.22 µm by vacuum filtration is reported. This membrane achieved an unprecedented water permeance above 819.1 LMH bar