Harvesting solar energy for water desalination is one of the most promising ways to produce clean water. Because of the absorber detachment and base material degradation, the solar steam generator still suffers from drastic energy loss even when using absorber materials with high photothermal conversion efficiency. We herein propose a practical desalination design that can maintain both the working efficiency and operating life. This device is made from the Paulownia wood covalently bonded with MXene on the top. Paulownia wood, as a natural heat insulator, servers as an excellent transport and customized evaporator. This heat absorber-Paulownia wood system achieved an evaporation rate of 1.465 kg m-2 h-1 at 1 sun irradiation, corresponding to 96% solar conversion efficiency. This method is proved to be universal, and the other two implemented materials, graphene oxide and the active carbon, on Paulownia wood were also demonstrated. The theoretical model based on two-phase flow in porous media further suggests this design can accelerate the distillate rate. In this article, the covalently bonded device shows a high solar-thermal conversion efficiency, excellent evaporation rate, and long-time durability, making it a superior candidate for water desalination.
Keywords: MXene; chemical process; durability; solar steam generator; wood.