Photothermal and hydrational dual-regulation in biomimetic biomass evaporators for enhanced solar steam generation

Solar-driven interfacial evaporation is a promising route to sustainable seawater desalination. However, challenges remain in achieving the dual regulation of photothermal conversion and hydration network for efficient evaporation. Inspired by natural photosynthesis, this study introduces a porphyrin metal-organic framework (MOF) wood evaporator, which enables simultaneous water evaporation, photocatalysis, and thermoelectric conversion under solar irradiation. The porphyrin MOF, serving as a dual platform for photothermal and photocatalytic applications, is anchored onto wood via stable chemical bonds. Meanwhile, the active groups on the porphyrin MOF improve the hydration network by binding to water molecules. Structural reconstruction rearranges loose cellulose fibers, forming an interwoven micro/nanocellulose network within the wood. This provides additional coordination sites for MOF anchoring. The prepared evaporator achieves an evaporation rate of 2.91 kg m^-2 h^-1, a H₂O₂ generation rate of 14.2 mmol m^-2 h^-1, and an output voltage of 50.2 mV under 1 sun irradiation. Density functional theory (DFT) calculations confirm that MOF incorporation substantially enhances evaporator-water interactions, reducing the evaporation enthalpy. Life cycle assessment (LCA) indicates that the prepared evaporator exhibits lower environmental impacts across multiple categories compared with three conventional desalination technologies. This work offers a sustainable route for solar-driven water evaporation.