Design of High‐Performance Bilayer Solar Evaporator Using Graphene‐Coated Bamboo Prepared by Near‐Infrared Laser‐Induced Carbonization of Polystyrene

Solar seawater evaporation is a sustainable seawater desalination technology. However, how to convert low‐cost waste general plastics into highly efficient photothermal materials remains a challenge. By using the idea of “near‐infrared laser‐induced carbonization” at room temperature and in air atmosphere, polystyrene (PS) can be easily converted into graphene. Bismuth oxide (Bi 2 O 3 ) catalyst is proven to efficiently convert laser energy into thermal energy and transmit it to the surrounding PS matrix, promoting carbonization. On this basis, by adjusting the catalyst content and the laser energy density per unit area, laser‐induced graphene (LIG) materials with high specific surface area, fast water transport, and high solar energy absorption efficiency can be obtained. Furthermore, the LIG materials are coated on the surface of natural bamboo with a capillary structure. This bilayer evaporation device has an evaporation rate of 1.51 kg m −2 h −1 and an energy conversion efficiency of 87.1% under irradiation of 1 sun. This work not only reveals the possibility of preparing high‐value‐added graphene materials from waste general‐purpose plastics, but also proves the application prospects of LIG materials in the field of solar seawater evaporation. This will provide a feasible approach for promoting the development of carbonization of waste general plastics.