Superhydrophilic 2D Covalent Organic Frameworks as Broadband Absorbers for Efficient Solar Steam Generation.

The intrinsic hydrophobicity and limited light absorption especially in the near-infrared (NIR) region of porous organic polymers are two bottlenecks impeding their applications in solar steam generation (SSG). Herein, we develop a 1,4,5,8-tetrakis(phenylamino)anthracene-9,10-dione (TPAD)-based covalent organic framework (COF) (TPAD-COF) featuring both superhydrophilicity and broad light absorption covering from the entire UV/Vis to NIR regions for SSG. TPAD-COF serving as a highly efficient photothermal conversion material without any additives displays an excellent water evaporation of 1.42 kg m-2 h-1 and achieves a high energy conversion efficiency of 94 % under 1 sun irradiation. Further extension of the light absorption range of the TPAD-based COF is realized through post-synthetic modification by chelating BF2 moieties. Systematic control experiments and analysis confirm that the hydrophilicity of photothermal conversion materials plays a more dominant role in the current TPAD-based COFs for SSG.

Facile synthesis of 3D covalent organic frameworks via a two-in-one strategy.

A "two-in-one" strategy was employed to construct 3D-COFs for the first time. Based on this strategy, a 3D-Flu-COF could be readily synthesized in various simplex organic solvents. Benefitting from the non-conjugated structure, the 3D-Flu-COF showcased excellent acidichromic sensing performance with good sensitivity, reversibility and naked eye visibility.