Facing the freshwater shortage and energy crisis, in order to achieve the goal of carbon dioxide emissions peaking and achieve carbon neutrality, researchers are devoted to seeking low-carbon, environmental-friendly and sustainable solutions. Recently, the sustainable freshwater generating strategy attracted much attraction about combining ‘green solar energy’ and ‘blue ocean energy’. Various methods have been explored to improve the energy conversion efficiency in generating freshwater and clean energy. Thus, the interfacial solar-vapor conversion technology became popular due to its high thermal utilization, photothermal conversion and vapor production rate. Due to its reproducibility and low cost, biochar as a kind of carbon-based photothermal material is used so often as solar absorber in the above interfacial system. In this review, we discuss five critical factors emphatically-materials, systems, hydrophily, water transport channel and salt-rejection designs-which, if addressed systematically, could increase the performance of biochar photothermal conversion devices. Meanwhile, we illuminate briefly the mechanism of photothermal conversion and the performance evaluation of biochar. Finally, the hot topics and challenges are summarized in the practical applications of biochar on desalination and energy generation, which provides a roadmap for the future development of the interfacial solar-vapor conversion technology. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.
