Emerging Photothermal Materials from Lignin and Coal for Solar Vapor Generation

Abstract Solar vapor generation (SVG) garners significant attention as a technology for producing clean water owing to its high efficiency and zero carbon emissions. However, the widespread adoption of SVG is constrained by the high cost, low mechanical strength, and complex fabrication processes of current photothermal materials. Lignin and coal, abundant in aromatic rings, C═O bonds, and quinone structures, present natural advantages for enhancing light absorption and improving the mechanical properties of photothermal materials. This review begins with an overview of the fundamentals of SVG and strategies aimed at promoting its efficiency. It then delves into the structural characteristics and photothermal conversion mechanisms of lignin and coal, highlighting their unique contributions to the field. Further, the latest advancements in the application of lignin/coal‐based photothermal materials for SVG are comprehensively summarized. This work not only lays a systematic and scientific foundation for the development of next‐generation photothermal materials but also underscores the potential for value‐added utilization of lignin and coal, thereby contributing to sustainable resource management.