Topology-Engineered Dual-Functional COFs with Spatially Cooperated Hydrophilic and Photocatalytic Sites for Harvesting Safe Water from Polluted Atmosphere

Abstract Atmospheric water harvesting (AWH) has emerged as a promising decentralized solution for freshwater supply in off-grid regions by extracting ubiquitous moisture from the air. However, the atmosphere also carries airborne pathogens and, under extreme scenarios, toxic chemicals, which can be coharvested to contaminate the collected water. Despite extensive efforts to maximize water uptake, the safety of the harvested water has been largely neglected in the pursuit of higher water production yields. Covalent organic frameworks (COFs) provide crystalline, molecularly programmable platforms for integrating water adsorption with photocatalytic detoxification. However, achieving such functional synergy depends on framework topology, which governs site accessibility and mass transport. Here, we report topology-engineered dual-functional COFs that regulate spatial cooperation among hydrophilic sites, photoactive sites, and pore structures in a series of 1D and 2D hydrazone COFs constructed from identical molecular building blocks. Compared to the compact 1D chain packing, the open and continuous channels of the 2D framework increase functional-site accessibility, support hydrogen-bonded water network formation, and facilitate charge-carrier separation and O2 activation. The optimized Por-TAH (2D) exhibits a saturated water uptake of 629 mg g–1, releases 94% of adsorbed water under mild heating, inactivates 99.99% of S. aureus within 1 h, and completely converts chemical agents with high selectivity within 10 min. As a proof-of-concept application, continuous-flow operation demonstrates integrated water harvesting and photocatalytic detoxification, yielding safe water free of detectable mustard gas simulants. This study establishes topology-directed spatial cooperation as a design principle for multifunctional porous materials, enabling safe water production from real contaminated air.