Highly Efficient TiO₂ Nanorods@CF based Solar Steam Generator

Harvesting solar energy via steam generation is an efficient way for brine and sewage water treatment. Directly bulk water heating with natural light yields low evaporation rates, owing to immense heat losses and its high heat capacity of water. Herein, we report styrofoam supported solar steam generator (SSG) comprised of glassy carbon foam (CF) covered with TiO₂ nanorods (TNRs). It shows a record high evaporation rate of 3.14 kgm^-2h^-1 under one sun irradiation. Such a high evaporation rate is mainly attributed to the synergetic effect of significant heat localization and reduction in enthalpy. Employing a low thermal conductivity, styrofoam naturally isolates the bulk water yielding an enhanced localization of heat. Concurrently, rapid water transport to SSG is ensured via a 2D air-laid paper as a wicking material. Moreover, the water molecules adsorbed in the form of clusters to the edges and tips of TNRs are more likely evaporate as clusters and thereby effectively reducing the enthalpy. Besides, the SSG offers broadband solar absorption displaying excellent photothermal conversion capability. Finally the facile method, low cost and longevity make our SSG a good candidate for application on a large scale.