Diatom-Inspired TiO₂-PANi-Decorated Bilayer Photothermal Foam for Solar-Driven Clean Water Generation

Interfacial solar-driven evaporation provides one of the most promising green and sustainable technologies to deal with the knotty water crisis by extracting vapor from a variety of water sources powered by solar energy. Advanced photothermal materials play critical roles in interfacial solar-driven evaporation by photothermal conversion and heat localization. Herein, inspired by the unique hierarchical structure and light-harvesting function of diatoms, we propose a novel photothermal material with a diatom-like hierarchical nanostructure derived from TiO₂-PANi-decorated bilayer melamine foam (TiO₂-PANi@MF) for solar-driven clean water generation. The diatom-like hierarchical nanostructured TiO₂-PANi@MF can realize full-spectrum light absorption and photothermal conversion by enhancing multiple light reflection and light scattering. Thanks to the diatom-like hierarchical nanostructure, TiO₂-PANi@MF not only impressively achieves an evaporation rate of 2.12 kg m^-2 h^-1 under 1 sun irradiation but also shows a high solar steam conversion efficiency up to 88.9%. Notably, the TiO₂-PANi composite also endows TiO₂-PANi@MF with photocatalytic degradation capability. Apart from the excellent steam generation capability, optimized TiO₂-PANi@MF also provides the high photocatalytic efficiency of dye degradation and maintains a high evaporation rate of more than 2 kg m^-2 h^-1. We believe that the proposed photothermal material with a diatom-like hierarchical nanostructure can envision promising practical applications in seawater desalination and sewage purification.