Carbon Dot Nano-Spacers in Triazine Networks for Integrated Photothermal Seawater Desalination and H₂O₂ Production

Solar-driven seawater desalination coupled with efficient H2O2 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 H₂O₂ 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 H₂O₂ 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.

© 2025 The Author(s). Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.