Freestanding Ultrathin Hierarchical PorousCarbon Blackbody Film

Solar energy powered interfacial evaporation is the most meaningful strategy for energy utilization, water desalination and mineral purification. It can achieve high efficiency, low-density energy and sustainable harvest and utilization. However, the suboptimal structure and surface/interface design still lead to an equilibrium between solar-thermal conversion, water conduction and thermal management. Here, a free-standing, ultra-thin two-dimension carbon film with a tunable nanopore diameter was prepared and used as a blackbody layer for solar photothermal evaporation. By the three-dimensional reconstruction methods, the effect of pore structure on interfacial evaporation is systematically studied. HPCF with an average pore size of about 300 nm exhibited outstanding photothermal evaporation performance, reaching up to 1.96 kg m−2 h−1 with excellent stability. Ultra-hydrophobic, optically enhanced absorption graphene array is constructed on the carbon film surface through femtosecond laser nano processing, further increasing the evaporation rate to 2.12 kg m−2 h−1 (1 sun) and 5.55 kg m−2 h−1 (3 suns)