Water Transport with Ultralow Friction through Partially Exfoliated g‐C₃N₄ Nanosheet Membranes with Self‐Supporting Spacers

Abstract

Two-dimensional (2D) graphitic carbon nitride (g-C₃ N₄ ) nanosheets show brilliant application potential in numerous fields. Herein, a membrane with artificial nanopores and self-supporting spacers was fabricated by assembly of 2D g-C₃ N₄ nanosheets in a stack with elaborate structures. In water purification the g-C₃ N₄ membrane shows a better separation performance than commercial membranes. The g-C₃ N₄ membrane has a water permeance of 29 L m^-2 h^-1 bar^-1 and a rejection rate of 87 % for 3 nm molecules with a membrane thickness of 160 nm. The artificial nanopores in the g-C₃ N₄ nanosheets and the spacers between the partially exfoliated g-C₃ N₄ nanosheets provide nanochannels for water transport while bigger molecules are retained. The self-supported nanochannels in the g-C₃ N₄ membrane are very stable and rigid enough to resist environmental challenges, such as changes to pH and pressure conditions. Permeation experiments and molecular dynamics simulations indicate that a novel nanofluidics phenomenon takes place, whereby water transport through the g-C₃ N₄ nanosheet membrane occurs with ultralow friction. The findings provide new understanding of fluidics in nanochannels and illuminate a fabrication method by which rigid nanochannels may be obtained for applications in complex or harsh environments.