Designing a bioinspired synthetic tree by unidirectional freezing for simultaneous solar steam generation and salt collection

Abstract Solar steam generation with thermal localization was recently proposed for highly efficient solar‐thermal desalination. However, to achieve high steam productivity with long term stability remains a critical challenge due to salt accumulation at the evaporation surface. Here, we designed a T‐shaped synthetic tree that could simultaneously achieve high steam productivity and salt collection with the structure characteristics of interfacial thermal evaporation, ambient energy harvesting and edge‐preferential crystallizing. Under 1 sun, the synthetic tree exhibited a steady water evaporation rate of 2.03 kg m⁻² hours⁻¹ over 60 hours, achieving solar thermal efficiency of 75%. Salt was continuously rejected at the edge of the evaporator with a steady collection rate of 59.879 g m⁻² hours⁻¹, which did not affect water evaporation. This new design principle to simultaneously harvest water and salt provides a new avenue for solar energy utilization. image