Dual-anion synergistic crosslinking tailoring pore structures in carbon-based hydrogels towards efficient salt-resistant solar steam generation

Carbon-based hydrogels are promising for solar interfacial evaporation, yet their relatively large pore structures reduce capillary force and limit efficient water transport. Therefore, we employ synergistic crosslinking between carboxymethyl cellulose (CMC) and sodium alginate (SA) for Ca 2 + to regulate the pore structure of hydrogels, and coal pitch-based porous carbon (ACP) is introduced as a photothermal material to construct the hydrogel evaporator ACP@SA/CMC-1. ACP@SA/CMC-1 exhibits a high intermediate water content of 72.6% and a reduced equivalent evaporation enthalpy of 1434.4 J·g −1 due to the optimized porous network and abundant hydrophilic functional groups. Meanwhile, the strong light-harvesting capability of ACP enables an overall solar absorption of 98.37%. Under an irradiation intensity of 1 kW·m −2 , ACP@SA/CMC-1 achieves an evaporation rate of 1.57 kg·m −2 ·h −1 . More importantly, ACP@SA/CMC-1 exhibits outstanding salt resistance, long-term stability, and durability during repeated salt deposition-dissolution cycles in high-salinity brine.