Marangoni effect induced by 2.5D evaporator enables anti-salt performance and long-term stability

Solar interface evaporator (SIE) driven seawater desalination technology has been verified to possess favorable feasibility. In this study, lychee charcoal, a representative resource from Guangxi, was loaded onto Cu foam via an ethanol calcination process to synthesize 2.5D Cu@Ti-C/M. The 2.5D architecture is a vertical extension of the 2D structure that avoids the complicated configuration of 3D structures. The 2.5D architecture induces the Marangoni effect, where surface liquid tension drives water backflow and inhibits salt precipitation. Meanwhile, 2.5D Cu@Ti-C/M forms new C–O–Cu bond through loading of lychee charcoal, thereby enhancing its light-absorption capacity. In addition, 2.5D Cu@Ti-C/M possesses small pore sizes to strengthen capillary force and accelerate water transport. Therefore, 2.5D Cu@Ti-C/M exhibits outstanding performance for photothermal seawater desalination.2.5D Cu@Ti-C/M achieves a light absorption rate of 96.89 % in the wavelength range of 200–1300 nm. The 2.5D Cu@Ti-C/M exhibits excellent hydrophilicity, with its contact angle dropping to 0° within 0.1 s. Under 1 kW·m −2 irradiation, 2.5D Cu@Ti-C/M reaches the evaporation rate of 3.13 kg⋅m −2 ⋅h −1 . The 2.5D Cu@Ti-C/M achieves a stable average evaporation rate of 3.09 kg·m −2 ·h −1 over 20 cycles under 1 kW·m −2 irradiation. Notably, the material maintains its structural integrity without salt accumulation, demonstrating exceptional long-term stability and photothermal performance. This study provides a feasible strategy for seawater desalination, enhancing the economic viability, universality, and reusability of SIE.