An asymmetric photothermal platform for coupled seawater splitting and desalination.

Lin, Jingkai; Xu, Hengyue; Tian, Wenjie; Sun, Hongqi; Zhang, Huayang; Wang, Shaobin · Nat Commun · 2026

basic_science · Level V

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Abstract

Photocatalytic seawater splitting provides a sustainable route to green hydrogen, but faces barriers of inefficiency and scalability. Graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>, CN) offers saline tolerance, yet its catalytic potential requires atomic-level control of structure and charge dynamics. Herein, we design three single-atom Co configurations on CN, including symmetric Co-N<sub>4</sub>, vacancy-anchored Co-N<sub>3</sub>, and asymmetric Co-N<sub>4</sub>. The asymmetric Co-N<sub>4</sub> in hierarchically porous carbon nitride (CoSA-hCN) introduces second-shell carbon vacancies that reshape electronic asymmetry and charge dynamics, establishing a robust pathway for effective salinity-mediated charge transfer and in situ Pt photodeposition for H<sub>2</sub> evolution. On a scalable 60 cm<sup>2</sup> floating photothermal platform under 1 sun, H<sub>2</sub> production (47.7 mmol m<sup>-2</sup> h<sup>-1</sup>) and interfacial seawater evaporation (1.88 kg m<sup>-2</sup> h<sup>-1</sup>) are achieved directly from natural seawater. In this work, we offer design principles for a single-atom catalyst on scalable photothermal platform for coupled seawater splitting and desalination.