Engineering of robust conjugated polymer-based aerogels via surface-initiated polycondensation towards sunlight-driven seawater desalination and uranium extraction

Abstract

The aerogels with low thermal conductivity and cross-linked 3D networks can be easily integrated with functional materials to maximize their functionalities, realizing diverse applications such as photothermal seawater desalination and photocatalytic uranium extraction. Sp²C-conjugated porous polymers (sp²C-CPPs) with robust and conjugated CC linkages are ideal photosensitizers for these applications, owing to their exceptional semiconducting properties as well as chemical stability. However, the limited processability and collectability of as-synthesized sp²C-CPP powders impede their extended applications. Herein, we report the preparation of robust sp²C-CPP (DHA-TMT and DBD-TMT) based aerogels via surface-initiated aldol polycondensation (SI-AP). The fully conjugated CC skeletons and electron-donating groups (–OH) endow the sp²C-CPP aerogels with excellent photothermal conversion efficiency (95.6%) and strong affinity for uranium adsorption. In particular, the DHA-TMT aerogel with hydrophilic porous channel exhibits a superb evaporation performance achieving ∼1.55 kg m⁻² h⁻¹ under AM 1.5 G while the fast mass transfer caused by photothermal conversion increases the uranium extraction capacity up to 1200 mg m⁻² in simulated seawater. Moreover, the sp²C-CPP aerogels demonstrate high stability under strong acid, base and brine solutions. This work shows a strategy for the preparation of uniform and high stability sp²C-CPP-based aerogels to simultaneously enhance their photothermal and photocatalytic performance.