Vacancy‐Engineered Single‐Atom MXene Membranes: A Quantum Leap in Ultrahigh‐Flux Nanoconfinement Catalysis for Robust Water Decontamination

Abstract Membrane‐based nanoconfinement catalytic oxidation (MNCO) offers promise for degrading persistent organic micropollutants (OMPs) in aqueous environments. Nevertheless, the intrinsic efficiency‐flux‐stability trade‐off impedes its further large‐scale engineering implementation. This study addresses this fundamental challenge through a first‐of‐its‐kind tripartite strategy encompassing atomic‐scale material design, mechanistic innovation, and structural engineering. A novel Co‐N‐Ti 3−x C 2 T y membrane is developed through vacancy‐mediated atomic trapping, constructing asymmetric Co‐N 1 C 2 sites on Ti‐defective MXene, synergizing hierarchical mass transfer optimization (Knudsen‐like flow, expanded external nanopores, minimized transport distance) with the nanoconfinement effect. This achieves an unprecedented high water flux of 2157 LMH, surpassing conventional membranes by 2−3 orders of magnitude, while maintaining 100% removal efficiency for various OMPs within 13.2 ms of retention time. Crucially, nanoconfinement and electronic delocalization at Co‐N 1 C 2 sites synergistically activate peroxymonosulfate to generate reactive oxygen species and accelerate catalyst‐mediated electron transfer, reducing formation energy barriers and diffusion distances, collectively culminating in 10 5 −10 7 ‐fold reaction kinetic enhancement relative to non‐confined analogues. Co single‐atom incorporation via Ti vacancies enhances structural integrity, ensuring stability in real water matrices and robustness for >130 h with <3% Co loss. This integrated design overcomes the catalytic membrane trilemma, enabling sustainable ultrafast decontamination and advancing MNCO for high‐performance, eco‐friendly purification systems toward global water security.