Endowing g‐C3N4 Membranes with Superior Permeability and Stability by Using Acid Spacers

g‐C3N4 membranes were modulated by intercalating molecules with SO3H and benzene moieties between layers. The intercalation molecules break up the tightly stacking structure of g‐C3N4 laminates successfully and accordingly the modified g‐C3N4 membranes give rise to two orders magnitude higher water permeances without sacrificing the separation efficiency. The sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO)/g‐C3N4 with a thickness of 350 nm presents an exceptionally high water permeance of 8867 L h−1 m−2 bar−1 and 100 % rejection towards methyl blue, while the original g‐C3N4 membrane with a thickness of 226 nm only exhibits a permeance of 60 L h−1 m−2 bar−1. Simultaneously, SO3H sites firmly anchor nitrogen with base functionality distributing onto g‐C3N4 through acid–base interactions. This enables the nanochannels of g‐C3N4 based membranes to be stabilized in acid, basic, and also high‐pressure environments for long periods. Acid spacers: Inspired by the architecture of graphene oxide laminates, we modulated g‐C3N4 membranes by intercalating SO3H and benzene moieties containing molecules between layers. The modified g‐C3N4 membranes give rise to two orders magnitude higher water permeances without sacrificing the separation efficiency, compared with the pure g‐C3N4 membrane.