High-performance graphene oxide nanofiltration membrane with continuous nanochannels prepared by the in situ oxidation of MXeneElectronic supplementary information (ESI) available: TEM image of GO; XPS spectra of MXene and TiO2 obtained via oxidation of MXene; EDS mapping of HGM10 membrane; 3D height AFM images of (a) HG, (b) HGM10, (c) HGM20, (d) HGM30; XRD patterns with partial enlarged detail of HG, HGM10, HGM20, HGM30; (a) Ti 2p XPS spectra of GO/MXene30 and back side of exfoliated HGM30, (b

Separation membrane with laminar structure, assembled by two-dimensional materials, has been widely explored to achieve precise molecular separation and high water permeability in the field of water purification. Herein, a novel GO-based nanofiltration membrane intercalated with TiO 2 nanoparticles was fabricated by the in situ oxidation of MXene nanosheets. The formation of TiO 2 nanocrystals, derived from the oxidation of MXene, created additional channels for water permeation. Particularly, the consecutively distributed TiO 2 nanocrystals acted as intercalators owing to their laminar structure and created continuous nanochannels within GO membrane for water transport, which shows great advantages over the membrane prepared using traditional methods. Water permeability of the obtained membrane reached 89.6 L m −2 h −1 bar −1 , which is 7.3 times that of pristine GO membrane and 2.4 times that of GO/TiO 2 membrane fabricated using traditional methods. The rejection rate for four different organic dyes is above 97%. The highly improved water permeability with no obvious sacrifice of rejection rate was attributed to the presence of continuous nanochannels obtained via the in situ oxidation of MXene without destroying the intrinsic stacking structure of GO sheets. This study offers a novel strategy to fabricate continuous nanochannels within the separation membrane with a two-dimensional laminar structure. MXene was used as a sacrificial template to create continuous nanochannels within GO-based nanofiltration membrane by in situ oxidation.