High‐Performance Large‐Scale Solar Steam Generation with Nanolayers of Reusable Biomimetic Nanoparticles

The harvesting of solar radiation for steam generation has drawn wide attention as a future sustainable technology for the renewable production of clean water worldwide. Here, a new super‐dark metasurface of 200 nm thickness is presented, which reaches a solar thermal efficiency of 87% when exposed to an intensity of only 2.3 sun, maintaining a stable efficiency of 90% at higher solar intensities. The metasurface is composed of extremely robust nanoparticles, which are up to 98% recyclable and can be produced on massively large scales by wet chemistry. By employing such reusable nanoparticles on an area of 1 m², 1.2 kg of seawater can be purified within only 1 h under natural sunshine. With such excellent performances, this nanomaterial can open new applications of high‐performance solar steam.