Two‐Dimensional Covalent Organic Framework Membranes: Multi‐Scale Design and Forward‐Looking Perspectives

Abstract

ABSTRACT Two‐dimensional covalent organic frameworks (2D COF) are attracting considerable attention as an emerging platform for membrane materials due to their well‐defined nanochannels, exceptional structural designability, high stability, and versatile synthesis routes. This review aims to establish a multiscale design framework to accelerate the advancement of 2D COF membranes. First, we systematically discuss engineering principles ranging from molecular‐scale monomer design, crystallinity control, transport‐channel engineering, and stacking modulation to macroscopic membrane processing. Second, we summarize and highlight recent progress in 2D COF membranes for various separation‐related applications, including gas separation, liquid purification, ion sieving, and energy storage and conversion. Finally, we identify key scientific and technological challenges and propose a roadmap to bridge laboratory innovations with industrial deployment. The outlined multiscale design principles and forward‐looking perspectives are expected to guide the rational development of 2D COF membranes for diverse environmental and energy applications.