Graphene-Based Materials for Solar-Driven Interfacial Evaporation: Materials Design, Salt Management, and Practical Challenges

Solar-driven interfacial evaporation (SDIE) provides a low-energy approach to desalination and water purification by localizing solar heat at the air-water interface instead of heating the entire water volume. Graphene and its derivatives have been widely investigated as photothermal absorbers because of their broad solar absorption, tunable surface chemistry, high light-to-heat conversion capability, and compatibility with porous architectures. This review summarizes recent progress in graphene oxide, reduced graphene oxide, and graphene-based composite absorbers for SDIE. The discussion focuses on material and structural design strategies that improve optical absorption, water transport, heat localization, vapor release, and salt resistance. Recent examples include light-trapping surface textures, Janus wettability gradients, three-dimensional hydrophilic networks, and hybrid systems that combine evaporation with water purification, photocatalysis, energy harvesting, or phase-change heat storage. These approaches have led to high evaporation rates and improved salt tolerance under laboratory conditions. However, practical application still requires further progress in long-term durability, mechanical stability, biofouling resistance, nanoparticle leaching prevention, cost reduction, and scalable fabrication of porous graphene structures. Finally, this review discusses future directions for developing robust and affordable graphene-based SDIE systems that can operate reliably under realistic seawater and outdoor conditions.