Carbon Dot Nano‐Spacers in Triazine Networks for Integrated Photothermal Seawater Desalination and H ₂ O ₂ Production

ABSTRACT Solar‐driven seawater desalination coupled with efficient H 2 O 2 generation represents a promising dual‐function strategy, advancing sustainable solutions for clean water and chemical production. Here, we report a metal‐free, photothermally active seawater evaporator utilizing carbon dots (CDs) embedded in a covalent triazine network (CTN) synthesized via cyclotrimerization of cyanated carbon dots (CN‐CDs). The CDs function as nano‐spacers that covalently link triazine units, thus enhancing the network's physicochemical properties and endowing it with significant photothermal catalytic activity. This low‐cost integrated photothermal‐catalytic system rapidly and efficiently produced desalinated water enriched with high concentrations of H 2 O 2 without the need for sacrificial agents and catalyst separation. This framework exhibits a solar‐to‐thermal efficiency of 44.3%, markedly superior to conventional covalent triazine frameworks and other carbon materials. Under simulated sunlight, it demonstrates robust photothermal catalytic H 2 O 2 production, achieving an impressive rate of 1066.7 μmol g −1 h −1 in seawater, with noteworthy desalination efficiency (82.71%). More importantly, it is readily scalable. This improvement marks a substantial advancement toward metal‐free photocatalysts with integrated photothermal properties, paving the way for the sustainable and scalable application of solar energy devices.