Superhydrophilic porous carbon foam as self-desalting monolithic solar steam generation device with high energy efficiency

The main challenge of interfacial solar steam generation (ISSG) for desalination is salt accumulation on solar absorber surface, thus significantly decreasing the evaporation efficiency. The most common method is design of a hydrophilic/hydrophobic multilayer composites system, where the upper hydrophobic layer is used for light absorption and the lower hydrophilic layer is used for pumping water. Obviously, such a complex multilayer system results in unsatisfactory efficiency and high cost of solar desalination. Here, we propose a novel strategy to address this issue using self-floating superhydrophilicity porous carbon foam (SPCF) used as integrative solar absorber for desalination, resulting from the powerful water pumping capability of SPCF. Salt from bulk water can be quickly re-dissolution in the 3D porous structure of SPCF, no salt accumulation was observed on the surface of SPCF in simulated seawater during 8 h desalination. Together with superior light absorptance (96.19%), ultrafast solar-thermal response (a temperature increases of 92.7 °C within 10 s under 2 sun), low thermal conductivity and outstanding mechanical robust, a high energy efficiency (86% at 1 sun) and simultaneous salt resistant for vapor generation are achieved. The findings provide a new perspective to design self-desalting monolithic ISSG to satisfy the demand for eco-friendly, low cost, highly efficient, and enduring solar desalination.